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Fang Z, Wanigasekara MSK, Yepremyan A, Lam B, Thapa P, Foss FW, Chowdhury SM. Mass Spectrometry-Cleavable Protein N-Terminal Tagging Strategy for System-Level Protease Activity Profiling. J Am Soc Mass Spectrom 2022; 33:189-197. [PMID: 34928623 DOI: 10.1021/jasms.1c00350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Proteolysis is one of the most important protein post-translational modifications (PTMs) that influences the functions, activities, and structures of nearly all proteins during their lifetime. To facilitate the targeted identification of low-abundant proteolytic products, we devised a strategy incorporating a novel biotinylated reagent PFP (pentafluorophenyl)-Rink-biotin to specifically target, enrich and identify proteolytic N-termini. Within the PFP-Rink-biotin reagent, a mass spectrometry (MS)-cleavable feature was designed to assist in the unambiguous confirmation of the enriched proteolytic N-termini. The proof-of-concept study was performed with multiple standard proteins whose N-termini were successfully modified, enriched and identified by a signature ion (SI) in the MS/MS fragmentation, along with the determination of N-terminal peptide sequences by multistage tandem MS of the complementary fragment generated after the cleavage of MS-cleavable bond. For large-scale application, the enrichment and identification of protein N-termini from Escherichia coli cells were demonstrated, facilitated by an in-house developed NTermFinder bioinformatics workflow. We believe this approach will be beneficial in improving the confidence of identifying proteolytic substrates in a native cellular environment.
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Affiliation(s)
- Zixiang Fang
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington Texas 76019, United States
| | - Maheshika S K Wanigasekara
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington Texas 76019, United States
| | - Akop Yepremyan
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington Texas 76019, United States
| | - Brandon Lam
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington Texas 76019, United States
| | - Pawan Thapa
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington Texas 76019, United States
| | - Frank W Foss
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington Texas 76019, United States
| | - Saiful M Chowdhury
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington Texas 76019, United States
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Andreazza F, Valbon WR, Wang Q, Liu F, Xu P, Bandason E, Chen M, Wu S, Smith LB, Scott JG, Jiang Y, Jiang D, Zhang A, Oliveira EE, Dong K. Sodium channel activation underlies transfluthrin repellency in Aedes aegypti. PLoS Negl Trop Dis 2021; 15:e0009546. [PMID: 34237076 PMCID: PMC8266078 DOI: 10.1371/journal.pntd.0009546] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 06/07/2021] [Indexed: 12/19/2022] Open
Abstract
Background Volatile pyrethroid insecticides, such as transfluthrin, have received increasing attention for their potent repellent activities in recent years for controlling human disease vectors. It has been long understood that pyrethroids kill insects by promoting activation and inhibiting inactivation of voltage-gated sodium channels. However, the mechanism of pyrethroid repellency remains poorly understood and controversial. Methodology/Principal findings Here, we show that transfluthrin repels Aedes aegypti in a hand-in-cage assay at nonlethal concentrations as low as 1 ppm. Contrary to a previous report, transfluthrin does not elicit any electroantennogram (EAG) responses, indicating that it does not activate olfactory receptor neurons (ORNs). The 1S-cis isomer of transfluthrin, which does not activate sodium channels, does not elicit repellency. Mutations in the sodium channel gene that reduce the potency of transfluthrin on sodium channels decrease transfluthrin repellency but do not affect repellency by DEET. Furthermore, transfluthrin enhances DEET repellency. Conclusions/Significance These results provide a surprising example that sodium channel activation alone is sufficient to potently repel mosquitoes. Our findings of sodium channel activation as the principal mechanism of transfluthrin repellency and potentiation of DEET repellency have broad implications in future development of a new generation of dual-target repellent formulations to more effectively repel a variety of human disease vectors. Vector-transmitted human diseases, such as dengue fever, represent serious global health burdens. Pyrethroids, including transfluthrin, are widely used as insecticides and repellents due to their low mammalian toxicity and relatively benign environmental impact. Pyrethroids target voltage-gated sodium channels for their insecticidal action. However, the mechanism of pyrethroid repellency remains unclear and controversial. Insect repellency is traditionally thought to be mediated by olfactory receptors. We made two important discoveries in this study, showing that transfluthrin repellency is via activation of sodium channels and transfluthrin enhances DEET repellency. Discovery of sodium channel activation as a major mechanism of pyrethroid repellency has broad significance in insect olfaction study, repellents development, and control of human disease vectors.
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Affiliation(s)
- Felipe Andreazza
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, Brazil
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Wilson R. Valbon
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, Brazil
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Qiang Wang
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
| | - Feng Liu
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
| | - Peng Xu
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
| | - Elizabeth Bandason
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
| | - Mengli Chen
- Institute of Pesticide and Environmental Toxicology, Zhejiang University, Hangzhou, China
| | - Shaoying Wu
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
| | - Leticia B. Smith
- Department of Entomology, Cornell University, Ithaca, New York, United States of America
| | - Jeffrey G. Scott
- Department of Entomology, Cornell University, Ithaca, New York, United States of America
| | - Youfa Jiang
- Jiangsu Yangnong Chemical Co., Ltd., Jiangsu, China
| | - Dingxin Jiang
- Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, China
| | - Aijun Zhang
- Invasive Insect Biocontrol and Behavior Laboratory, Beltsville Agricultural Research Center-West, USDA-ARS, Beltsville, Maryland, United States of America
| | - Eugenio E. Oliveira
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Entomology, Universidade Federal de Viçosa, Viçosa, Brazil
| | - Ke Dong
- Department of Entomology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Biology, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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Turnock S, Turton DR, Martins CD, Chesler L, Wilson TC, Gouverneur V, Smith G, Kramer-Marek G. 18F-meta-fluorobenzylguanidine ( 18F-mFBG) to monitor changes in norepinephrine transporter expression in response to therapeutic intervention in neuroblastoma models. Sci Rep 2020; 10:20918. [PMID: 33262374 PMCID: PMC7708446 DOI: 10.1038/s41598-020-77788-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023] Open
Abstract
Targeted radiotherapy with 131I-mIBG, a substrate of the human norepinephrine transporter (NET-1), shows promising responses in heavily pre-treated neuroblastoma (NB) patients. Combinatorial approaches that enhance 131I-mIBG tumour uptake are of substantial clinical interest but biomarkers of response are needed. Here, we investigate the potential of 18F-mFBG, a positron emission tomography (PET) analogue of the 123I-mIBG radiotracer, to quantify NET-1 expression levels in mouse models of NB following treatment with AZD2014, a dual mTOR inhibitor. The response to AZD2014 treatment was evaluated in MYCN amplified NB cell lines (Kelly and SK-N-BE(2)C) by Western blot (WB) and immunohistochemistry. PET quantification of 18F-mFBG uptake post-treatment in vivo was performed, and data correlated with NET-1 protein levels measured ex vivo. Following 72 h AZD2014 treatment, in vitro WB analysis indicated decreased mTOR signalling and enhanced NET-1 expression in both cell lines, and 18F-mFBG revealed a concentration-dependent increase in NET-1 function. AZD2014 treatment failed however to inhibit mTOR signalling in vivo and did not significantly modulate intratumoural NET-1 activity. Image analysis of 18F-mFBG PET data showed correlation to tumour NET-1 protein expression, while further studies are needed to elucidate whether NET-1 upregulation induced by blocking mTOR might be a useful adjunct to 131I-mIBG therapy.
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Affiliation(s)
- Stephen Turnock
- Preclinical Molecular Imaging, Division of Radiotherapy and Imaging, The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK
| | - David R Turton
- PET Radiochemistry, Division of Radiotherapy and Imaging, The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK
| | - Carlos Daniel Martins
- Preclinical Molecular Imaging, Division of Radiotherapy and Imaging, The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK
| | - Louis Chesler
- Division of Clinical Studies, The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK
| | - Thomas C Wilson
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Véronique Gouverneur
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Graham Smith
- PET Radiochemistry, Division of Radiotherapy and Imaging, The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK
| | - Gabriela Kramer-Marek
- Preclinical Molecular Imaging, Division of Radiotherapy and Imaging, The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK.
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Czernel G, Budziak I, Oniszczuk A, Karcz D, Pustuła K, Górecki A, Matwijczuk A, Gładyszewska B, Gagoś M, Niewiadomy A, Matwijczuk A. ESIPT-Related Origin of Dual Fluorescence in the Selected Model 1,3,4-Thiadiazole Derivatives. Molecules 2020; 25:molecules25184168. [PMID: 32933032 PMCID: PMC7570705 DOI: 10.3390/molecules25184168] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 11/16/2022] Open
Abstract
In our previous work, we discussed the emergence of the dual fluorescence phenomenon in selected compounds from the group of 1,3,4-thiadiazoles. The results obtained in a number of experimental studies, supported by [TD]DFT calculations, clearly indicated that the phenomenon of dual fluorescence stemmed from an overlap of several factors, including the correct conformation of the analyzed molecule and, very significantly in this context, aggregation effects. Where those two conditions were met, we could observe the phenomenon of intermolecular charge transfer (CT) and the emergence of electronic states responsible for long wave emissions. However, in light of the new studies presented in this paper, we were able, for the first time, to provide a specific theory for the effect of dual fluorescence observed in the analyzed group of 1,3,4-thiadiazoles. We present the results of spectroscopic measurements conducted for two selected analogues from the 1,3,4-thiadiazole group, both in polar and non-polar solvents, which clearly evidence (as we have already suspected in the past, albeit have not shown in publications to date) the possibility of processes related to emission from the tautomer formed in the process of excited state intramolecular proton transfer, which is responsible for the long-wavelength emissions observed in the selected analogues. The presented results obtained with the use of UV-Vis, fluorescence (stationary and time-resolved), FTIR, and Raman spectroscopy, as well as from calculations of dipole moment changes between the ground and excited state with the use of two derivatives with different structures of the resorcylic system, corroborated our standing hypothesis. At the same time, they excluded the presence of ground state keto forms of the analyzed analogues unless necessitated by the structure of the molecule itself. In this case, aggregation factors enhance the observed effects related to the dual fluorescence of the analyzed compounds (by way of AIE-aggregated induced emissions).
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Affiliation(s)
- Grzegorz Czernel
- Department of Biophysics, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland; (G.C.); (A.M.); (B.G.)
| | - Iwona Budziak
- Department of Chemistry, University of Life Sciences in Lublin, Akademicka 15, 20-950 Lublin, Poland;
| | - Anna Oniszczuk
- Department of Inorganic Chemistry, Medical University in Lublin, 20-059 Lublin, Poland
- Correspondence: (A.O.); (D.K.); (A.M.); Tel.: +48-814-456-937 (A.M.); Fax: +48-814-456-684 (A.M.)
| | - Dariusz Karcz
- Department of Analytical Chemistry (C1), Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska 24, 31-155 Cracow, Poland
- Correspondence: (A.O.); (D.K.); (A.M.); Tel.: +48-814-456-937 (A.M.); Fax: +48-814-456-684 (A.M.)
| | - Katarzyna Pustuła
- Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Kraków, Poland;
| | - Andrzej Górecki
- Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology of the Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland;
| | - Alicja Matwijczuk
- Department of Biophysics, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland; (G.C.); (A.M.); (B.G.)
| | - Bożena Gładyszewska
- Department of Biophysics, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland; (G.C.); (A.M.); (B.G.)
| | - Mariusz Gagoś
- Department of Cell Biology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Akademicka 19, 20-033 Lublin, Poland;
| | - Andrzej Niewiadomy
- Institute of Industrial Organic Chemistry, Annopol 6, 03-236 Warsaw, Poland;
| | - Arkadiusz Matwijczuk
- Department of Biophysics, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland; (G.C.); (A.M.); (B.G.)
- Correspondence: (A.O.); (D.K.); (A.M.); Tel.: +48-814-456-937 (A.M.); Fax: +48-814-456-684 (A.M.)
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Skubic C, Vovk I, Rozman D, Križman M. Simplified LC-MS Method for Analysis of Sterols in Biological Samples. Molecules 2020; 25:molecules25184116. [PMID: 32916848 PMCID: PMC7571030 DOI: 10.3390/molecules25184116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 12/30/2022] Open
Abstract
We developed a simple and robust liquid chromatographic/mass spectrometric method (LC-MS) for the quantitative analysis of 10 sterols from the late part of cholesterol synthesis (zymosterol, dehydrolathosterol, 7-dehydrodesmosterol, desmosterol, zymostenol, lathosterol, FFMAS, TMAS, lanosterol, and dihydrolanosterol) from cultured human hepatocytes in a single chromatographic run using a pentafluorophenyl (PFP) stationary phase. The method also avails on a minimized sample preparation procedure in order to obtain a relatively high sample throughput. The method was validated on 10 sterol standards that were detected in a single chromatographic LC-MS run without derivatization. Our developed method can be used in research or clinical applications for disease-related detection of accumulated cholesterol intermediates. Disorders in the late part of cholesterol synthesis lead to severe malformation in human patients. The developed method enables a simple, sensitive, and fast quantification of sterols, without the need of extended knowledge of the LC-MS technique, and represents a new analytical tool in the rising field of cholesterolomics.
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Affiliation(s)
- Cene Skubic
- Center for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, SI-1000 Ljubljana, Slovenia; (C.S.); (D.R.)
| | - Irena Vovk
- Department of Food Chemistry, National Institute of Chemistry, Ljubljana, Hajdrihova 19, SI-1000 Ljubljana, Slovenia;
| | - Damjana Rozman
- Center for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Zaloška cesta 4, SI-1000 Ljubljana, Slovenia; (C.S.); (D.R.)
| | - Mitja Križman
- Department of Food Chemistry, National Institute of Chemistry, Ljubljana, Hajdrihova 19, SI-1000 Ljubljana, Slovenia;
- Correspondence: ; Tel./Fax: +386-1-4760-266
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Otsuka M, Miyaguchi H, Uchiyama M. Analysis of nitrogen mustard degradation products via post-pentafluorobenzoylation liquid chromatography-tandem mass spectrometry. J Chromatogr A 2020; 1625:461306. [PMID: 32709349 DOI: 10.1016/j.chroma.2020.461306] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/03/2020] [Accepted: 06/03/2020] [Indexed: 01/09/2023]
Abstract
A pentafluorobenzoylation (PFBz)-liquid chromatography-tandem mass spectrometry method was developed for qualitative and quantitative analysis of ethanolamines (EAs, nitrogen mustard degradation products). With this method, highly hydrophilic EAs can be sufficiently analyzed with a commonly used reversed phase column (retention times: (PFBz)2-methyl diethanolamine, 9.1 min; (PFBz)2-ethyl diethanolamine, 9.8 min; and (PFBz)3-triethanolamine, 17.6 min). The applicability of the method for real samples was investigated via recovery tests. Methyl diethanolamine and ethyl diethanolamine were detected at concentrations as low as 1 ng/mL in serum and 10 ng/mL in urine, and quantified within the range of 1-1000 ng/mL and 10-1000 ng/mL, respectively.
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Affiliation(s)
- Mai Otsuka
- National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan; Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan.
| | - Hajime Miyaguchi
- National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882, Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan; Cluster of Pioneering Research (CPR), Advanced Elements Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Simmons EC, Scholpa NE, Cleveland KH, Schnellmann RG. 5-hydroxytryptamine 1F Receptor Agonist Induces Mitochondrial Biogenesis and Promotes Recovery from Spinal Cord Injury. J Pharmacol Exp Ther 2020; 372:216-223. [PMID: 31776207 PMCID: PMC6978694 DOI: 10.1124/jpet.119.262410] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/22/2019] [Indexed: 01/08/2023] Open
Abstract
Spinal cord injury (SCI) is characterized by vascular disruption leading to ischemia, decreased oxygen delivery, and loss of mitochondrial homeostasis. This mitochondrial dysfunction results in loss of cellular functions, calcium overload, and oxidative stress. Pharmacological induction of mitochondrial biogenesis (MB) may be an effective approach to treat SCI. LY344864, a 5-hydroxytryptamine 1F (5-HT1F) receptor agonist, is a potent inducer of MB in multiple organ systems. To assess the efficacy of LY344864-induced MB on recovery post-SCI, female mice were subjected to moderate force-controlled impactor-induced contusion SCI followed by daily LY344864 administration for 21 days. Decreased mitochondrial DNA and protein content was present in the injury site 3 days post-SCI. LY344864 treatment beginning 1 h after injury attenuated these decreases, indicating MB. Additionally, injured mice treated with LY344864 displayed decreased Evan's Blue dye accumulation in the spinal cord compared with vehicle-treated mice 7 days after injury, suggesting restoration of vascular integrity. LY344864 also increased locomotor capability, with treated mice reaching a Basso-Mouse Scale score of 3.4 by 21 days, whereas vehicle-treated mice exhibited a score of 1.9. Importantly, knockout of the 5-HT1F receptor blocked LY344864-induced recovery. Remarkably, a similar degree of locomotor restoration was observed when treatment initiation was delayed until 8 h after injury. Furthermore, cross-sectional analysis of the spinal cord 21 days after injury revealed decreased lesion volume with delayed LY344864 treatment initiation, emphasizing the potential clinical applicability of this therapeutic approach. These data provide evidence that induction of MB via 5-HT1F receptor agonism may be a promising strategy for the treatment of SCI. SIGNIFICANCE STATEMENT: Treatment with LY344864 induces mitochondrial biogenesis in both the naive and injured mouse spinal cord. In addition, treatment with LY344864 beginning after impactor-induced contusion spinal cord injury improves mitochondrial homeostasis, blood-spinal cord barrier integrity, and locomotor function within 7 days. Importantly, similar locomotor results are observed whether treatment is initiated at 1 h after injury or 8 h after injury. These data indicate the potential for pharmacological induction of mitochondrial biogenesis through a 5-hydroxytryptamine 1F agonist as a novel therapeutic approach for spinal cord injury.
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Affiliation(s)
- Epiphani C Simmons
- Department of Pharmacology and Toxicology, College of Pharmacy (E.C.S., N.E.S., K.H.C., R.G.S.), Department of Neurosciences, College of Medicine (E.C.S., R.G.S.), Southwest Environmental Health Science Center (R.G.S.), and Center for Innovation in Brain Science (R.G.S.), University of Arizona, Tucson, Arizona; and Southern Arizona VA Health Care System, Tucson, Arizona (R.G.S.)
| | - Natalie E Scholpa
- Department of Pharmacology and Toxicology, College of Pharmacy (E.C.S., N.E.S., K.H.C., R.G.S.), Department of Neurosciences, College of Medicine (E.C.S., R.G.S.), Southwest Environmental Health Science Center (R.G.S.), and Center for Innovation in Brain Science (R.G.S.), University of Arizona, Tucson, Arizona; and Southern Arizona VA Health Care System, Tucson, Arizona (R.G.S.)
| | - Kristan H Cleveland
- Department of Pharmacology and Toxicology, College of Pharmacy (E.C.S., N.E.S., K.H.C., R.G.S.), Department of Neurosciences, College of Medicine (E.C.S., R.G.S.), Southwest Environmental Health Science Center (R.G.S.), and Center for Innovation in Brain Science (R.G.S.), University of Arizona, Tucson, Arizona; and Southern Arizona VA Health Care System, Tucson, Arizona (R.G.S.)
| | - Rick G Schnellmann
- Department of Pharmacology and Toxicology, College of Pharmacy (E.C.S., N.E.S., K.H.C., R.G.S.), Department of Neurosciences, College of Medicine (E.C.S., R.G.S.), Southwest Environmental Health Science Center (R.G.S.), and Center for Innovation in Brain Science (R.G.S.), University of Arizona, Tucson, Arizona; and Southern Arizona VA Health Care System, Tucson, Arizona (R.G.S.)
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8
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Chen Q, Wang Y, Hua R. Base-Promoted Chemodivergent Formation of 1,4-Benzoxazepin-5(4 H)-ones and 1,3-Benzoxazin-4(4 H)-ones Switched by Solvents. Molecules 2019; 24:molecules24203773. [PMID: 31635103 PMCID: PMC6832296 DOI: 10.3390/molecules24203773] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/13/2019] [Accepted: 10/18/2019] [Indexed: 02/06/2023] Open
Abstract
The KOH-promoted chemodivergent benzannulation of ortho-fluorobenzamides with 2-propyn-1-ol can afford either 1,4-benzoxazepin-5(4H)-ones or 1,3-benzoxazin-4(4H)-ones in good yields with high selectivity, depending greatly upon the use of solvents. In the case of using DMSO, the intermolecular benzannulation produced seven-membered benzo-fused heterocycles of 1,4-benzoxazepin-5(4H)-ones, whereas in MeCN, the six-membered benzo-fused heterocycles of 1,3-benzoxazin-4(4H)-ones were formed. The KOH-promoted benzannulation proceeded most probably through the C–F nucleophilic substitution of ortho-fluorobenzamides with 2-propyn-1-ol to give the intermediate of ortho-[(2-propynyl)oxy]benzamide, which underwent the intramolecular hydroamidation in a different manner to afford either seven- or six-membered benzo-fused heterocycles.
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Affiliation(s)
- Qian Chen
- Department of Chemistry, Tsinghua University, Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Beijing 100084, China.
| | - Yunpeng Wang
- Department of Chemistry, Tsinghua University, Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Beijing 100084, China.
| | - Ruimao Hua
- Department of Chemistry, Tsinghua University, Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Beijing 100084, China.
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Abstract
Misfolding and abnormal assembly of proteins cause many intractable diseases. The modulation of the assembly process of these proteins could contribute to understanding and controlling amyloid protein aggregation. Previous works focused mainly on the inhibition of the assembly process. To broaden the interaction modality of modulators with proteins for developing new modulators, in this work, we designed and synthesized two reactive poly ( p-phenylene vinylene) polymers, respectively, functionalized with N-hydroxysuccinimide ester (PPV-NHS) and pentafluorophenol ester (PPV-PFP), which exhibited the prevention or co-assembly effect on the aggregation process of islet amyloid polypeptide (IAPP). Cell assays demonstrated that both of the two polymers could effectively eliminate the cytotoxicity of IAPP. Moreover, PPV-NHS also could irreversibly disrupt preformed IAPP fibrils. We envision that PPV-NHS and PPV-PFP might offer a new design method for the modulation of protein assembly.
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Affiliation(s)
- Han Sun
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100910 , P. R. China
- College of Chemistry , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Fengting Lv
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100910 , P. R. China
- College of Chemistry , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Libing Liu
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100910 , P. R. China
- College of Chemistry , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
| | - Shu Wang
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry , Chinese Academy of Sciences , Beijing 100910 , P. R. China
- College of Chemistry , University of Chinese Academy of Sciences , Beijing 100049 , P. R. China
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Abstract
Targeting RNA drastically expands our target space to therapeutically modulate numerous cellular processes implicated in human diseases. Of particular interest, drugging pre-mRNA splicing appears a very viable strategy; to control levels of splicing product by promoting the inclusion or exclusion of exons. After describing the concept of "splicing modulation", this chapter will cover the outstanding progress achieved in this field, by highlighting the breakthrough accomplished recently for the treatment of spinal muscular atrophy using two therapeutic modalities: splice switching oligonucleotides and small molecules. This review discusses the vital but feasible requirement for such drugs to deliver selectivity, and critical safety aspects are highlighted. Transformational medicines such as those developed to treat SMA are likely just the beginning of this story.
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Affiliation(s)
- Hasane Ratni
- F. Hoffmann-La Roche Ltd., pRED, Pharma Research & Early Development, Roche Innovation Center Basel, Basel, Switzerland.
| | - Lutz Mueller
- F. Hoffmann-La Roche Ltd., pRED, Pharma Research & Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Martin Ebeling
- F. Hoffmann-La Roche Ltd., pRED, Pharma Research & Early Development, Roche Innovation Center Basel, Basel, Switzerland
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11
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Abstract
PURPOSE Cell-based therapies are showing great promise for a variety of diseases, but remain hindered by the limited information available regarding the biological fate, migration routes and differentiation patterns of infused cells in trials. Previous studies have demonstrated the feasibility of using positron emission tomography (PET) to track single cells utilising an approach known as positron emission particle tracking (PEPT). The radiolabel hexadecyl-4-[18F]fluorobenzoate ([18F]HFB) was identified as a promising candidate for PEPT, due to its efficient and long-lasting labelling capabilities. The purpose of this work was to characterise the labelling efficiency of [18F]HFB in vitro at the single-cell level prior to in vivo studies. PROCEDURES The binding efficiency of [18F]HFB to MDA-MB-231 and Jurkat cells was verified in vitro using bulk gamma counting. The measurements were subsequently repeated in single cells using a new method known as radioluminescence microscopy (RLM) and binding of the radiolabel to the single cells was correlated with various fluorescent dyes. RESULTS Similar to previous reports, bulk cell labelling was significantly higher with [18F]HFB (18.75 ± 2.47 dpm/cell, n = 6) than 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) (7.59 ± 0.73 dpm/cell, n = 7; p ≤ 0.01). However, single-cell imaging using RLM revealed that [18F]HFB accumulation in live cells (8.35 ± 1.48 cpm/cell, n = 9) was not significantly higher than background levels (4.83 ± 0.52 cpm/cell, n = 12; p > 0.05) and was 1.7-fold lower than [18F]FDG uptake in the same cell line (14.09 ± 1.90 cpm/cell, n = 13; p < 0.01). Instead, [18F]HFB was found to bind significantly to fragmented membranes associated with dead cell nuclei, suggesting an alternative binding target for [18F]HFB. CONCLUSION This study demonstrates that bulk analysis alone does not always accurately portray the labelling efficiency, therefore highlighting the need for more routine screening of radiolabels using RLM to identify heterogeneity at the single-cell level.
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Affiliation(s)
- Louise Kiru
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Tae Jin Kim
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Bin Shen
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Frederick T Chin
- Department of Radiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Guillem Pratx
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA.
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12
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Jang J, Son J, Park E, Kosaka T, Saxon JA, De Clercq DJH, Choi HG, Tanizaki J, Eck MJ, Jänne PA, Gray NS. Discovery of a Highly Potent and Broadly Effective Epidermal Growth Factor Receptor and HER2 Exon 20 Insertion Mutant Inhibitor. Angew Chem Int Ed Engl 2018; 57:11629-11633. [PMID: 29978938 PMCID: PMC6118895 DOI: 10.1002/anie.201805187] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/26/2018] [Indexed: 12/11/2022]
Abstract
Exon 20 insertion (Ex20Ins) mutations are the third most prevalent epidermal growth factor receptor (EGFR) activating mutation and the most prevalent HER2 mutation in non-small cell lung cancer (NSCLC). Novel therapeutics for the patients with Ex20Ins mutations are urgently needed, due to their poor responses to the currently approved EGFR and HER2 inhibitors. Here we report the discovery of highly potent and broadly effective EGFR and HER2 Ex20Ins mutant inhibitors. The co-crystal structure of compound 1 b in complex with wild type EGFR clearly revealed an additional hydrophobic interaction of 4-fluorobenzene ring within a deep hydrophobic pocket, which has not been widely exploited in the development of EGFR and HER2 inhibitors. As compared with afatinib, compound 1 a exhibited superior inhibition of proliferation and signaling pathways in Ba/F3 cells harboring either EGFR or HER2 Ex20Ins mutations, and in the EGFR P772_H773insPNP patient-derived lung cancer cell line DFCI127. Our study identifies promising strategies for development of EGFR and HER2 Ex20Ins mutant inhibitors.
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Affiliation(s)
- Jaebong Jang
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Jieun Son
- Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Eunyoung Park
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Takayuki Kosaka
- Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Jamie A Saxon
- Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Dries J H De Clercq
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Hwan Geun Choi
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Junko Tanizaki
- Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Michael J Eck
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Pasi A Jänne
- Lowe Center for Thoracic Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Nathanael S Gray
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
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13
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Zheng Z, Zhang C, Shi H, Liu Z, Duan J, Wang M. Photolysis of cyflufenamid in liquid media. Water Sci Technol 2018; 78:424-431. [PMID: 30101777 DOI: 10.2166/wst.2018.312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The photolysis of cyflufenamid (CFA) in different organic solvents and water under ultraviolet irradiation was investigated. The photolytic rate constant and photolytic half-life were measured for the different solutions. Factors influencing the photolysis of CFA were investigated, including initial concentration, types of solvent, pH, occurrence of catalyst (TiO2), and environmental substances (Fe3+, Fe2+, NO3 -, NO2 -). Photolysis of CFA followed first-order kinetics in various systems, and the photolytic rate of CFA decreased with increased initial concentration. Photolytic rates of CFA in different solvents were as follows: n-hexane > methanol > acetonitrile > ultrapure water > ethyl acetate. The pH had a significant effect on the photolysis of CFA, and the photolysis rate reached its peak at pH 9.0. NO2 - and TiO2 had positive effects on the photolysis of CFA, while Fe2+ had an adverse effect. NO3 - in aqueous solution had no effect on the photolysis of CFA. In addition, the rates of photolysis were accelerated at lower concentrations of Fe3+ (0.5-5 mmol L-1) and decreased at higher concentrations (10 mmol L-1). Moreover, a main photolytic product of CFA was confirmed to be N-cyclopropoxy-2,3-difluoro-6-(trifluoromethyl)benzamide, and cleavage of the amido bond was proposed to be the predicted photolysis pathway in n-hexane.
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Affiliation(s)
- Zhangyu Zheng
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, China
| | - Chunyan Zhang
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, China
| | - Haiyan Shi
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, China
| | - Zhiwei Liu
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, China
| | - Jinsheng Duan
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, China; Institute of Plant Protection and Agro-Products Safety, Anhui Academy of Agricultural Sciences, Key Laboratory of Agro-Product Safety Risk Evaluation (Hefei), Hefei 230031, China E-mail:
| | - Minghua Wang
- Department of Pesticide Science, College of Plant Protection, Nanjing Agricultural University, State and Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing 210095, China
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14
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Gilbertson SR, Chen YC, Soto CA, Yang Y, Rice KC, Cunningham KA, Anastasio NC. Synthesis and activity of functionalizable derivatives of the serotonin (5-HT) 5-HT 2A receptor (5-HT 2AR) antagonist M100907. Bioorg Med Chem Lett 2018; 28:1381-1385. [PMID: 29555153 DOI: 10.1016/j.bmcl.2018.02.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 02/28/2018] [Indexed: 01/19/2023]
Abstract
The approach of tethering together two known receptor ligands, to be used as molecular probes for the study of G protein-coupled receptor (GPCR) systems, has proven to be a valuable approach. Selective ligands that possess functionality that can be used to link to other ligands, are useful in the development of novel antagonists and agonists. Such molecules can also be attached to reporter molecules, such as fluorophores, for the study of GPCR dimerization and its role in signaling. The highly selective serotonin (5-HT) 5-HT2A receptor (5-HT2AR) antagonist M100907 (volinanserin) is of clinical interest in the treatment of neurological and mental health disorders. Here, we synthesized the most active (+)-M100907 enantiomer as well as a series of derivatives that possessed either an alkyne or an azide. The triazole resulting from the dipolar cycloaddition of these groups did not interfere with the ability of the bivalent ligand to act as an antagonist. Thus, we have synthesized a number of compounds which will prove useful in elucidating the role of the 5-HT2AR in the central nervous system.
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Affiliation(s)
- Scott R Gilbertson
- Department of Chemistry, University of Houston, Houston, TX, United States; Center for Addiction Research, United States.
| | - Ying-Chu Chen
- Department of Chemistry, University of Houston, Houston, TX, United States
| | | | - Yaxing Yang
- Department of Chemistry, University of Houston, Houston, TX, United States
| | - Kenner C Rice
- Drug Design and Synthesis Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Bethesda, MD, United States
| | - Kathryn A Cunningham
- Center for Addiction Research, United States; Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Noelle C Anastasio
- Center for Addiction Research, United States; Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
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15
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Kovacevic G, Sabljic A. Atmospheric oxidation of halogenated aromatics: comparative analysis of reaction mechanisms and reaction kinetics. Environ Sci Process Impacts 2017; 19:357-369. [PMID: 28002503 DOI: 10.1039/c6em00577b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Atmospheric transport is the major route for global distribution of semi-volatile compounds such as halogenated aromatics as well as their major exposure route for humans. Their major atmospheric removal process is oxidation by hydroxyl radicals. There is very little information on the reaction mechanism or reaction-path dynamics of atmospheric degradation of halogenated benzenes. Furthermore, the measured reaction rate constants are missing for the range of environmentally relevant temperatures, i.e. 230-330 K. A series of recent theoretical studies have provided those valuable missing information for fluorobenzene, chlorobenzene, hexafluorobenzene and hexachlorobenzene. Their comparative analysis has provided additional and more general insight into the mechanism of those important tropospheric degradation processes as well as into the mobility, transport and atmospheric fate of halogenated aromatic systems. It was demonstrated for the first time that the addition of hydroxyl radicals to monohalogenated as well as to perhalogenated benzenes proceeds indirectly, via a prereaction complex and its formation and dynamics have been characterized including the respective transition-state. However, in fluorobenzene and chlorobenzene reactions hydroxyl radical hydrogen is pointing approximately to the center of the aromatic ring while in the case of hexafluorobenzene and hexachlorobenzene, unexpectedly, the oxygen is directed towards the center of the aromatic ring. The reliable rate constants are now available for all environmentally relevant temperatures for the tropospheric oxidation of fluorobenzene, chlorobenzene, hexafluorobenzene and hexachlorobenzene while pentachlorophenol, a well-known organic micropollutant, seems to be a major stable product of tropospheric oxidation of hexachlorobenzene. Their calculated tropospheric lifetimes show that fluorobenzene and chlorobenzene are easily removed from the atmosphere and do not have long-range transport potential while hexafluorobenzene seems to be a potential POP chemical and hexachlorobenzene is clearly a typical persistent organic pollutant.
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Affiliation(s)
- Goran Kovacevic
- Rudjer Boskovic Institute, Division of Physical Chemistry, POB 180, HR-10002 Zagreb, Republic of Croatia.
| | - Aleksandar Sabljic
- Rudjer Boskovic Institute, Division of Physical Chemistry, POB 180, HR-10002 Zagreb, Republic of Croatia.
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16
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Tsikas D. Pentafluorobenzyl bromide-A versatile derivatization agent in chromatography and mass spectrometry: I. Analysis of inorganic anions and organophosphates. J Chromatogr B Analyt Technol Biomed Life Sci 2016; 1043:187-201. [PMID: 27561968 DOI: 10.1016/j.jchromb.2016.08.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/05/2016] [Accepted: 08/09/2016] [Indexed: 11/19/2022]
Abstract
Pentafluorobenzyl bromide (PFB-Br) is a versatile derivatization agent. It is widely used in chromatography and mass spectrometry since several decades. The bromide atom is largely the single leaving group of PFB-Br. It is substituted by wide a spectrum of nucleophiles in aqueous and non-aqueous systems to form electrically neutral, in most organic solvents soluble, generally thermally stable, volatile, strongly electron-capturing and ultraviolet light-absorbing derivatives. Because of these greatly favoured physicochemical properties, PFB-Br emerged an ideal derivatization agent for highly sensitive analysis of endogenous and exogenous substances including various inorganic and organic anions by electron capture detection or after electron-capture negative-ion chemical ionization in GC-MS. The present article attempts an appraisal of the utility of PFB-Br in analytical chemistry. It reviews and discusses papers dealing with the use of PFB-Br as the derivatization reagent in the qualitative and quantitative analysis of endogenous and exogenous inorganic anions in various biological samples, notably plasma, urine and saliva. These analytes include nitrite, nitrate, cyanide and dialkyl organophosphates. Special emphasis is given to mass spectrometry-based approaches and stable-isotope dilution techniques.
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Affiliation(s)
- Dimitrios Tsikas
- Centre of Pharmacology and Toxicology, Hannover Medical School, 30623 Hannover, Germany.
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17
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Mfuh AM, Doyle JD, Chhetri B, Arman HD, Larionov OV. Scalable, Metal- and Additive-Free, Photoinduced Borylation of Haloarenes and Quaternary Arylammonium Salts. J Am Chem Soc 2016; 138:2985-8. [PMID: 26914533 PMCID: PMC4974080 DOI: 10.1021/jacs.6b01376] [Citation(s) in RCA: 209] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report herein a simple, metal- and additive-free, photoinduced borylation of haloarenes, including electron-rich fluoroarenes, as well as arylammonium salts directly to boronic acids. This borylation method has a broad scope and functional group tolerance. We show that it can be further extended to boronic esters and carried out on gram scale as well as under flow conditions.
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Affiliation(s)
- Adelphe M. Mfuh
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - John D. Doyle
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Bhuwan Chhetri
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Hadi D. Arman
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Oleg V. Larionov
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
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18
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Horstmann S, Sonneck R. Contact Bioassays with Phenoxybenzyl and Tetrafluorobenzyl Pyrethroids against Target-Site and Metabolic Resistant Mosquitoes. PLoS One 2016; 11:e0149738. [PMID: 26930058 PMCID: PMC4773128 DOI: 10.1371/journal.pone.0149738] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 02/04/2016] [Indexed: 11/26/2022] Open
Abstract
Background Mosquito strains that exhibit increased tolerance to the chemical class of compounds with a sodium channel modulator mode of action (pyrethroids and pyrethrins) are typically described as “pyrethroid resistant”. Resistance to pyrethroids is an increasingly important challenge in the control of mosquito-borne diseases, such as malaria or dengue, because one of the main interventions (the distribution of large numbers of long-lasting insecticide-treated bed nets) currently relies entirely on long-lasting pyrethroids. Increasing tolerance of target insects against this class of insecticides lowers their impact in vector control. The current study suggests that the level of metabolic resistance depends on the structure of the molecule and that structurally different compounds may still be effective because detoxifying enzymes are unable to bind to these uncommon structures. Methods Treated surface contact bioassays were performed on susceptible Aedes aegypti, East African knockdown resistance (kdr) Anopheles gambiae (strain RSP-H) and metabolically resistant Anopheles funestus (strain FUMOZ-R) with different pyrethroids, such as cypermethrin, ß-cyfluthrin, deltamethrin, permethrin and transfluthrin (alone and in combination with the synergist piperonyl butoxide). The nonfluorinated form of transfluthrin was also assessed as a single agent and in combination with piperonyl butoxide. Results Although the dosages for pyrethroids containing a phenoxybenzyl moiety have exhibited differences in terms of effectiveness among the three tested mosquito species, the structurally different transfluthrin with a polyfluorobenzyl moiety remained active in mosquitoes with upregulated P450 levels. In trials with transfluthrin mixed with piperonyl butoxide, the added synergist exhibited no efficacy-enhancing effect. Conclusion The results of this study suggest that transfluthrin has the potential to control P450-mediated metabolically resistant mosquitoes because the structural formula of transfluthrin differs from that of the tested pyrethroids, which are used in vector control. The P450-detoxifying enzymes of the Anopheles funestus FUMOZ-R mosquitoes seem to bind preferably at the phenoxybenzyl moiety and appear to be unable to degrade transfluthrin with its tetrafluorobenzyl moiety. Inhibition of the class of monooxygenases by piperonyl butoxide revealed no increase of efficacy of the pure transfluthrin compound, which also indicates that the P450 enzymes potentially do not impact the efficacy of transfluthrin.
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19
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Masoom H, Courtier-Murias D, Soong R, Maas WE, Fey M, Kumar R, Monette M, Stronks HJ, Simpson MJ, Simpson AJ. From Spill to Sequestration: The Molecular Journey of Contamination via Comprehensive Multiphase NMR. Environ Sci Technol 2015; 49:13983-13991. [PMID: 26579583 DOI: 10.1021/acs.est.5b03251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Comprehensive multiphase NMR is a novel NMR technique that permits all components (solutions, gels, and solids) to be studied in unaltered natural samples. In this study a wide range of CMP-NMR interaction and editing-based experiments are combined to follow contaminants (pentafluorophenol (PFP) and perfluorooctanoic acid (PFOA)) from the solution state (after a spill) through the gel-state and finally into the true solid-state (sequestered) in an intact water-swollen soil. Kinetics experiments monitoring each phase illustrate PFOA rapidly transfers from solution to the solid phase while for PFP the process is slower with longer residence times in the solution and gel phase. Interaction-based experiments reveal that PFOA enters the soil via its hydrophobic tails and selectively binds to soil microbial protein. PFP sorption shows less specificity exhibiting interactions with a range of gel and solid soil components with a preference toward aromatics (mainly lignin). The results indicate that in addition to more traditional measurements such as Koc, other factors including the influence of the contaminant on the soil-water interface, specific biological interactions, soil composition (content of lignin, protein, etc.) and physical accessibility/swellability of soil organic components will likely be central to better explaining and predicting the true behavior of contaminants in soil.
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Affiliation(s)
- Hussain Masoom
- Department of Chemistry, University of Toronto , Toronto, Ontario Canada , M1C 1A4
| | | | - Ronald Soong
- Department of Chemistry, University of Toronto , Toronto, Ontario Canada , M1C 1A4
| | - Werner E Maas
- Bruker BioSpin Corp., Billerica, Massachusetts 01821-3991, United States
| | - Michael Fey
- Bruker BioSpin Corp., Billerica, Massachusetts 01821-3991, United States
| | - Rajeev Kumar
- Bruker BioSpin Canada, Milton, Ontario Canada , L9T 1Y6
| | | | | | - Myrna J Simpson
- Department of Chemistry, University of Toronto , Toronto, Ontario Canada , M1C 1A4
| | - André J Simpson
- Department of Chemistry, University of Toronto , Toronto, Ontario Canada , M1C 1A4
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20
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Sun ZN, Yang Q, Ji DL, Zheng L. [Degradation of 3,4- Dichlorobenzotrifluoride by Fe3O4/CeO2-H2O2 Heterogeneous Fenton-Like Systems]. Huan Jing Ke Xue 2015; 36:2154-2160. [PMID: 26387320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The 3,4-Dichlorobenzotrifluoride (3,4-DCBTE) was dehalogenated with oxidation treatment by heterogeneous Fenton-like system, using nanoscale Fe304/CeO2 as a catalyst. This nanoscale catalyst was prepared by the impregnated method. As a highly active new heterogeneous Fenton-like catalyst, nanoscale Fe304/CeO2 not only has the characteristics of the traditional Fenton-like catalyst but also can prevent the secondary pollution which caused by Fe2+. To find the optimum catalytic conditions for nanoscale Fe3O4/CeO2, the influence factors were investigated. The results indicated that the degradation ratio of 3,4-DCBTE was significantly improved by adding nanoscale Fe3O4/CeO2, with the removal ratio reaching 97.76% in 120 minutes and 79.85% in 20 minutes. As the temperature increasing, the catalytic effect of nanoscale Fe3O4/CeO2 catalyst had been constantly improved obviously. As the pH decreased, the degradation ratio of 3,4-DCBTE increased. With the increase of dosage of hydrogen peroxide (H2O2), the degradation efficiency of 3,4-DCBTE initially increased and then decreased, because oxygen (O2) was generated in preferential self-reaction when an excess of (H2O2) was added. The optimum removal efficiency was observed with the dosage of 15 mg x L(-1). With the increased amount of catalyst, there was a same trend as dosage of hydrogen peroxide (H2O2). The degradation ratio of 3,4-DCBTE initially increased and then decreased, the optimum amount of catalyst was 0.5 g x L(-1). The results also suggested that the reaction process followed the first-order kinetics and the thermodynamic analysis demonstrated that the reaction was only needed low reaction activation energy.
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21
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Gleeson EC, Graham JE, Spiller S, Vetter I, Lewis RJ, Duggan PJ, Tuck KL. Inhibition of N-type calcium channels by fluorophenoxyanilide derivatives. Mar Drugs 2015; 13:2030-45. [PMID: 25871286 PMCID: PMC4413198 DOI: 10.3390/md13042030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 03/18/2015] [Accepted: 03/26/2015] [Indexed: 12/26/2022] Open
Abstract
A set of fluorophenoxyanilides, designed to be simplified analogues of previously reported ω-conotoxin GVIA mimetics, were prepared and tested for N-type calcium channel inhibition in a SH-SY5Y neuroblastoma FLIPR assay. N-type or Cav2.2 channel is a validated target for the treatment of refractory chronic pain. Despite being significantly less complex than the originally designed mimetics, up to a seven-fold improvement in activity was observed.
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MESH Headings
- Analgesics, Non-Narcotic/chemical synthesis
- Analgesics, Non-Narcotic/chemistry
- Analgesics, Non-Narcotic/metabolism
- Analgesics, Non-Narcotic/pharmacology
- Anilides/chemical synthesis
- Anilides/chemistry
- Anilides/metabolism
- Anilides/pharmacology
- Binding, Competitive
- Calcium Channel Blockers/chemical synthesis
- Calcium Channel Blockers/chemistry
- Calcium Channel Blockers/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Channels, N-Type/chemistry
- Calcium Channels, N-Type/metabolism
- Calcium Signaling/drug effects
- Cell Line, Tumor
- Drug Design
- Fluorobenzenes/chemical synthesis
- Fluorobenzenes/chemistry
- Fluorobenzenes/metabolism
- Fluorobenzenes/pharmacology
- High-Throughput Screening Assays
- Humans
- Molecular Structure
- Molecular Targeted Therapy
- Nerve Tissue Proteins/antagonists & inhibitors
- Nerve Tissue Proteins/metabolism
- Neuralgia/drug therapy
- Neuralgia/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Neurotoxins/chemistry
- Pain, Intractable/drug therapy
- Pain, Intractable/metabolism
- Structure-Activity Relationship
- omega-Conotoxin GVIA/chemistry
- omega-Conotoxin GVIA/metabolism
- omega-Conotoxin GVIA/pharmacology
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Affiliation(s)
- Ellen C Gleeson
- School of Chemistry, Monash University, Clayton VIC 3800, Australia.
- CSIRO Manufacturing Flagship, Clayton South, VIC 3169, Australia.
| | - Janease E Graham
- School of Chemistry, Monash University, Clayton VIC 3800, Australia.
- CSIRO Manufacturing Flagship, Clayton South, VIC 3169, Australia.
| | - Sandro Spiller
- School of Chemistry, Monash University, Clayton VIC 3800, Australia.
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia QLD 4072, Australia.
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia QLD 4072, Australia.
| | - Peter J Duggan
- CSIRO Manufacturing Flagship, Clayton South, VIC 3169, Australia.
- School of Chemical and Physical Sciences, Flinders University, Adelaide SA 5042, Australia.
| | - Kellie L Tuck
- School of Chemistry, Monash University, Clayton VIC 3800, Australia.
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22
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Yoon JY, Na EJ, Lee SJ, Kim YK, Yoon SS. Blue Emitting Materials Based on Naphthylanthracene Derivatives Containing Electron-Withdrawing Fluorobenzenes. J Nanosci Nanotechnol 2015; 15:1628-1631. [PMID: 26353704 DOI: 10.1166/jnn.2015.9326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We have designed and synthesized three blue emitters based on 9-naphthylanthracene derivatives connected with various electron-withdrawing group such as 4-fluorobenzene, 2,4-difluorobenzene and 2,3,4,5,6-pentafluorobenzene (1-3). Multilayered OLEDs with the structure of ITO (180 nm)/NPB (50 nm)/Blue materials 1-3 (30 nm)/TPBi (15 nm)/Liq (2 nm)/AI (100 nm) have been fabricated to investigate their electroluminescent properties. In particular, the device using 3 showed efficient blue electroluminescent properties with a luminous, power, external quantum efficiency and CIE coordinates of 0.71 cd/A, 1.98 Im/W, 1.34% at 20 mA/cm2 and (x = 0.16, y = 0.20) at 10.0 V, respectively. In addition, a deep blue OLED using 1 with CIE coordinates (x = 0.15, y = 0.11) at 10.0 V exhibited a luminous, power, external quantum efficiency of 2.12 cd/A, 3.04 Im/W and 1.17% at 20 mA/cm2, respectively.
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23
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Machado TC, Pizzolato TM, Arenzon A, Segalin J, Lansarin MA. Photocatalytic degradation of rosuvastatin: analytical studies and toxicity evaluations. Sci Total Environ 2015; 502:571-577. [PMID: 25300021 DOI: 10.1016/j.scitotenv.2014.09.076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 09/22/2014] [Accepted: 09/22/2014] [Indexed: 06/04/2023]
Abstract
Photocatalytic degradation of rosuvastatin, which is a drug that has been used to reduce blood cholesterol levels, was studied in this work employing ZnO as catalyst. The experiments were carried out in a temperature-controlled batch reactor that was irradiated with UV light. Preliminary the effects of the photocatalyst loading, the initial pH and the initial rosuvastatin concentration were evaluated. The experimental results showed that rosuvastatin degradation is primarily a photocatalytic process, with pseudo-first order kinetics. The byproducts that were generated during the oxidative process were identified using nano-ultra performance liquid chromatography tandem mass spectrometry (nano-UPLC-MS/MS) and acute toxicity tests using Daphnia magna were done to evaluate the toxicity of the untreated rosuvastatin solution and the reactor effluent.
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Affiliation(s)
- Tiele Caprioli Machado
- Chemical Engineering Department, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert s/n, CEP: 90040-040 Porto Alegre, RS, Brazil.
| | - Tânia Mara Pizzolato
- Chemical Institute, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, CEP: 91501-970 Porto Alegre, RS, Brazil
| | - Alexandre Arenzon
- Ecology Center, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, CEP: 91501-970 Porto Alegre, RS, Brazil
| | - Jeferson Segalin
- Biotechnology Center, Federal University of Rio Grande do Sul, Avenida Bento Gonçalves, 9500, CEP: 91501-970 Porto Alegre, RS, Brazil
| | - Marla Azário Lansarin
- Chemical Engineering Department, Federal University of Rio Grande do Sul, Rua Engenheiro Luiz Englert s/n, CEP: 90040-040 Porto Alegre, RS, Brazil
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24
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Liang J, Hoepker AC, Bruneau AM, Ma Y, Gupta L, Collum DB. Lithium diisopropylamide-mediated lithiation of 1,4-difluorobenzene under nonequilibrium conditions: role of monomer-, dimer-, and tetramer-based intermediates and lessons about rate limitation. J Org Chem 2014; 79:11885-902. [PMID: 25000303 PMCID: PMC4275155 DOI: 10.1021/jo501392r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Indexed: 11/29/2022]
Abstract
Lithiation of 1,4-difluorobenzene with lithium diisopropylamide (LDA) in THF at -78 °C joins the ranks of a growing number of metalations that occur under conditions in which the rates of aggregate exchanges are comparable to the rates of metalation. As such, a substantial number of barriers vie for rate limitation. Rate studies reveal that rate-limiting steps and even the choice of reaction coordinate depend on subtle variations in concentration. Deuteration shifts the rate-limiting step and markedly alters the concentration dependencies and overall rate law. This narrative is less about ortholithiation per se and more about rate limitation and the dynamics of LDA aggregate exchange.
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Affiliation(s)
- Jun Liang
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell
University, Ithaca, New York 14853-1301, United States
| | - Alexander C. Hoepker
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell
University, Ithaca, New York 14853-1301, United States
| | - Angela M. Bruneau
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell
University, Ithaca, New York 14853-1301, United States
| | - Yun Ma
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell
University, Ithaca, New York 14853-1301, United States
| | - Lekha Gupta
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell
University, Ithaca, New York 14853-1301, United States
| | - David B. Collum
- Department of Chemistry and
Chemical Biology, Baker Laboratory, Cornell
University, Ithaca, New York 14853-1301, United States
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25
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Gómez-Caravaca AM, Verardo V, Berardinelli A, Marconi E, Caboni MF. A chemometric approach to determine the phenolic compounds in different barley samples by two different stationary phases: a comparison between C18 and pentafluorophenyl core shell columns. J Chromatogr A 2014; 1355:134-42. [PMID: 24958035 DOI: 10.1016/j.chroma.2014.06.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/29/2014] [Accepted: 06/03/2014] [Indexed: 01/26/2023]
Abstract
Barley (Hordeum vulgare L.) is a cereal crop that has been cultivated since ancient times. However, its interest as nutritional food and as food ingredient is relatively new. Thus, in this study, the phenolic compounds of eighteen different varieties of barley (4 waxy and 14 non-waxy) grown under the same agronomic conditions in the same experimental field have been determined by HPLC-DAD-MS. Two new methodologies were developed using new generation superficially porous HPLC columns with different stationary phases: C18 and pentafluorophenyl (PFP). Twelve free phenolic compounds and eight bound phenolic compounds could be identified in barley samples in less than 22min. The study of different method parameters showed that C18 column was more suitable for the analysis of phenolic compounds of barley. Hierarchical cluster analysis (HCA) was conducted in order to assess the different ability of the two different core shell HPLC columns in the discrimination between "waxy" and "non-waxy" varieties, and only HCA of C18 column could separate waxy and non-waxy genotypes. Significant differences in the content of phenolic compounds between waxy and non-waxy samples were found, being waxy barley samples the ones which presented higher content of free and bound phenolic compounds. Once the best discriminant HPLC column was established, principal component analysis (PCA) was applied and it was able to discriminate between "waxy" and "non-waxy" varieties; however it discriminated the barley samples based only in free phenolic compounds. Because of that, partial least squares discriminant analysis (PLS-DA) and Artificial Neural Networks (ANN) were carried out. PLS-DA and ANN permitted the classification of waxy and non-waxy genotypes from both free and bound phenolic compounds.
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Affiliation(s)
- Ana María Gómez-Caravaca
- Department of Analytical Chemistry, University of Granada, c/Fuentenueva s/n, E-18071 Granada, Spain; Research and Development of Functional Food Centre (CIDAF), PTS Granada, Avda. del Conocimiento s/n, Edificio Bioregión, E-18007 Granada, Spain.
| | - Vito Verardo
- Inter-Departmental Centre for Agri-Food Industrial Research (CIRI Agroalimentare), University of Bologna, P.zza Goidanich 60, I-47521 Cesena (FC), Italy
| | - Annachiara Berardinelli
- Inter-Departmental Centre for Agri-Food Industrial Research (CIRI Agroalimentare), University of Bologna, P.zza Goidanich 60, I-47521 Cesena (FC), Italy
| | - Emanuele Marconi
- Dipartimento Agricoltura, Ambiente e Alimenti, Università del Molise, via De Sanctis, I-86100 Campobasso (CB), Italy; Università Campus Bio-Medico di Roma, via Álvaro del Portillo, 21, I-00128 Roma, Italy
| | - Maria Fiorenza Caboni
- Inter-Departmental Centre for Agri-Food Industrial Research (CIRI Agroalimentare), University of Bologna, P.zza Goidanich 60, I-47521 Cesena (FC), Italy; Department of Agricultural and Food Sciences, Alma Mater Studiorum-University of Bologna, Piazza Goidanich, 60, I-47521 Cesena (FC), Italy
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26
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Takemura A, McAllister LJ, Hart S, Pridmore NE, Karadakov PB, Whitwood AC, Bruce DW. Halogen- and hydrogen-bonded salts and co-crystals formed from 4-halo-2,3,5,6-tetrafluorophenol and cyclic secondary and tertiary amines: orthogonal and non-orthogonal halogen and hydrogen bonding, and synthetic analogues of halogen-bonded biological systems. Chemistry 2014; 20:6721-32. [PMID: 24796890 PMCID: PMC4324131 DOI: 10.1002/chem.201402128] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Indexed: 12/15/2022]
Abstract
Co-crystallisation of, in particular, 4-iodotetrafluorophenol with a series of secondary and tertiary cyclic amines results in deprotonation of the phenol and formation of the corresponding ammonium phenate. Careful examination of the X-ray single-crystal structures shows that the phenate anion develops a C=O double bond and that the C-C bond lengths in the ring suggest a Meissenheimer-like delocalisation. This delocalisation is supported by the geometry of the phenate anion optimised at the MP2(Full) level of theory within the aug-cc-pVDZ basis (aug-cc-pVDZ-PP on I) and by natural bond orbital (NBO) analyses. With sp(2) hybridisation at the phenate oxygen atom, there is strong preference for the formation of two non-covalent interactions with the oxygen sp(2) lone pairs and, in the case of secondary amines, this occurs through hydrogen bonding to the ammonium hydrogen atoms. However, where tertiary amines are concerned, there are insufficient hydrogen atoms available and so an electrophilic iodine atom from a neighbouring 4-iodotetrafluorophenate group forms an I⋅⋅⋅O halogen bond to give the second interaction. However, in some co-crystals with secondary amines, it is also found that in addition to the two hydrogen bonds forming with the phenate oxygen sp(2) lone pairs, there is an additional intermolecular I⋅⋅⋅O halogen bond in which the electrophilic iodine atom interacts with the C=O π-system. All attempts to reproduce this behaviour with 4-bromotetrafluorophenol were unsuccessful. These structural motifs are significant as they reproduce extremely well, in low-molar-mass synthetic systems, motifs found by Ho and co-workers when examining halogen-bonding interactions in biological systems. The analogy is cemented through the structures of co-crystals of 1,4-diiodotetrafluorobenzene with acetamide and with N-methylbenzamide, which, as designed models, demonstrate the orthogonality of hydrogen and halogen bonding proposed in Ho's biological study.
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Affiliation(s)
- Akihiro Takemura
- Department of Chemistry, University of York, Heslington, York YO10 5DD (UK)
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27
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Ujihara K, Mori T, Iwasaki T, Sugano M, Shono Y, Matsuo N. Metofluthrin: A Potent New Synthetic Pyrethroid with High Vapor Activity against Mosquitoes. Biosci Biotechnol Biochem 2014; 68:170-4. [PMID: 14745180 DOI: 10.1271/bbb.68.170] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
(1R)-trans-Norchrysanthemic acid fluorobenzyl esters are synthesized and their structure-activity relationships are discussed. These esters show outstanding insecticidal activity against mosquitoes. In particular, the 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl analog (metofluthrin) exhibits the highest potency, being approximately forty times as potent as d-allethrin in a mosquito coil formulation when tested against southern house mosquitoes (Culex quinquefasciatus). Metofluthrin also exhibits a significant vapor action at room temperature.
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Affiliation(s)
- Kazuya Ujihara
- Agricultural Chemicals Research Laboratory, Sumitomo Chemical Co., Ltd, Hyogo, Japan.
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28
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Suliman FO, Al-Nafai I, Al-Busafi SN. Synthesis, characterization and DFT calculation of 4-fluorophenyl substituted tris(8-hydroxyquinoline)aluminum(III) complexes. Spectrochim Acta A Mol Biomol Spectrosc 2014; 118:66-72. [PMID: 24036308 DOI: 10.1016/j.saa.2013.08.055] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 08/06/2013] [Accepted: 08/14/2013] [Indexed: 06/02/2023]
Abstract
New 4-fluorophenyl substituted 8-hydroxyquinoline derivatives, 5-(4-fluorophenyl)quinolin-8-ol and 5,7-bis(4-fluorophenyl)quinolin-8-ol, were synthesized and characterized by spectroscopic methods. The aluminum complexes of 5-(4-fluorophenyl)quinolin-8-ol (AlQF) and of 5,7-bis(4-fluorophenyl)quinolin-8-ol (AlQF2) exhibit strong fluorescence emission centered at 525 nm and 530 nm respectively. The quantum yield of both complexes were enhanced compared to the parent tris(8-hydroxyquinolinato)aluminum(III) complex. Electronic structures and photophysical properties of the new complexes were investigated theoretically by ab initio and density functional theory (DFT) and time dependent DFT (TD-DFT). Geometries of the ground state (S0) and the first excited state (S1) of the new complexes were optimized at the B3LYP/6-31G(d) functional and configuration interaction singles (CIS) method respectively. The aryl substituents were found to contribute significantly to the frontier molecular orbitals (FMOs). We have observed that in both cases the lowest occupied molecular orbital (LUMO) energy decreases while the energy of the highest occupied molecular orbital is slightly increased. The most significant increase was observed for AlQF2.
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Affiliation(s)
- Fakhreldin O Suliman
- Department of Chemistry, College of Science, Sultan Qaboos University, Box 36, Al-Khod 123, Sultanate of Oman, Oman.
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29
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Yan D, Williams GR, Zhao M, Li C, Fan G, Yang H. Flexible free-standing luminescent two-component fiber films with tunable hierarchical structures based on hydrogen-bonding architecture. Langmuir 2013; 29:15673-15681. [PMID: 24274340 DOI: 10.1021/la4034657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Although the fabrication of hierarchical architectures with highly ordered functional units is of great importance for both fundamental science and practical application, the development of one-dimensional (1D) organic hierarchical micro/nanostructures based on low-molecular-weight (LMW) building blocks remains at an early stage. Herein, we report two types of micro/nanoscaled multicomponent fluorescent fiber systems with tunable hierarchical morphologies through a one-step coassembly process. With the aid of hydrogen-bonding motifs, LMW precursors (1,4-bis(5-phenyloxazol-2-yl)benzene (A) and two coassembled building blocks: 4-bromotetrafluorobenzene carboxylic acid (B) and 2,3,4,5,6-pentafluorophenol (C)) have been self-organized into fibers and flexible free-standing films, which show hierarchical micro/nanostructures as well as tunable one-/two-photon luminescence. The disassembly of the multicomponent A.B and A.C fibers occurs at high temperature, which further alters the luminescence properties of the multicomponent materials. Therefore, this work provides a facile wet chemical route for fabricating multicomponent LMW self-assembled fibers and free-standing film systems with tunable hierarchical structures and photoemission behaviors, and such self-organized systems may have potential applications in fields of two-photon luminescence and thermal sensors.
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Affiliation(s)
- Dongpeng Yan
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology , Beijing 100029, P. R. China
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30
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Abstract
Halogenated aromatics are one of the largest chemical classes of environmental contaminants, and dehalogenation remains one of the most important processes by which these compounds are degraded and detoxified. The thermodynamic constraints of aromatic dehalogenation reactions are thus important for understanding the feasibility of such reactions and the redox conditions necessary for promoting them. Accordingly, the thermochemical properties of the (poly)fluoro-, (poly)chloro-, and (poly)bromobenzenes, including standard enthalpies of formation, bond dissociation enthalpies, free energies of reaction, and the redox potentials of Ar-X/Ar-H couples, were investigated using a validated density functional protocol combined with continuum solvation calculations when appropriate. The results highlight the fact that fluorinated aromatics stand distinct from their chloro- and bromo- counterparts in terms of both their relative thermodynamic stability toward dehalogenation and how different substitution patterns give rise to relevant properties, such as bond strengths and reduction potentials.
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Affiliation(s)
- Daniel Sadowsky
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich , 8092 Zurich, Switzerland
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31
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Baumgartner R, Stieger GK, McNeill K. Complete hydrodehalogenation of polyfluorinated and other polyhalogenated benzenes under mild catalytic conditions. Environ Sci Technol 2013; 47:6545-6553. [PMID: 23663092 DOI: 10.1021/es401183v] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Polyfluorinated arenes are increasingly used in industry and can be considered emerging contaminants. Environmentally applicable degradation methods leading to full defluorination are not reported in the literature. In this study, it is demonstrated that the heterogeneous catalyst Rh/Al2O3 is capable of fully defluorinating and hydrogenating polyfluorinated benzenes in water under mild conditions (1 atm H2, ambient temperature) with degradation half-lives between 11 and 42 min. Analysis of the degradation rates of the 12 fluorobenzene congeners showed two trends: slower degradation with increasing number of fluorine substituents and increasing degradation rates with increasing number of adjacent fluorine substituents. The observed fluorinated intermediates indicated that adjacent fluorine substituents are preferably removed. Besides defluorination and hydrogenation, the scope of the catalyst includes dehalogenation of polychlorinated benzenes, bromobenzene, iodobenzene, and selected mixed dihalobenzenes. Polychlorobenzene degradation rates, like their fluorinated counterparts, decreased with increasing halogen substitution. In contrast to the polyfluorobenzenes though, removal of chlorine substituents was sterically driven. All monohalobenzenes were degraded at similar rates; however, when two carbon-halogen bonds were in direct intramolecular competition, the weaker bond was broken first. Differences in sorption affinities of the substrates are suggested to play a major role in determining the relative rates of transformation of halobenzenes by Rh/Al2O3 and H2.
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Affiliation(s)
- Rebekka Baumgartner
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zurich, Switzerland
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32
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Wang J, Zhu R, Qin C, Wang Y, Zhang S, Zhang B. Vibrational spectra and trace determination of p-difluorobenzene and ethylbenzene. Spectrochim Acta A Mol Biomol Spectrosc 2013; 107:1-7. [PMID: 23416902 DOI: 10.1016/j.saa.2013.01.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Revised: 01/14/2013] [Accepted: 01/17/2013] [Indexed: 06/01/2023]
Abstract
In this work, the structures and normal vibrations of p-difluorobenzene and ethylbenzene in the first excited state have been studied using resonant two-photon ionization spectrum and ab initio quantum chemical calculations. A vibronic spectrum of p-difluorobenzene has been reinvestigated in some detail and three new vibrational modes, 260(1), 130(1) and 30(1), are assigned respectively. The band origin of ethylbenzene of the S1←S0 transition appeared at 37,586 cm(-1), and more vibrational modes are observed. These appropriate structures and vibrational frequencies of the S0 and S1 states of both molecules are calculated using Hartree-Fock and configuration interaction singles methods with 6-311++G(2d, 2p) basis set. All spectral bands of both molecules have been successfully assigned with the help of our computed results and analogy with the reported spectra for similar molecules. The strongest transition 50(1) of p-difluorobenzene is selected to measure a concentration detective limit of the setup system and the achieved concentration detective limit is 3.125 ppb.
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Affiliation(s)
- Jian Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China
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33
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Lee EM, Gwon SY, Son YA, Kim SH. Fluorescence quenching of carbazole by 2-chloro-3,5-dinitrobenzotrifluoride-ethylamines intermolecular charge-transfer complex. Spectrochim Acta A Mol Biomol Spectrosc 2013; 103:453-455. [PMID: 23266014 DOI: 10.1016/j.saa.2012.11.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/02/2012] [Accepted: 11/06/2012] [Indexed: 06/01/2023]
Abstract
The interaction between carbazole and 2-chloro-3,5-dinitrobenzotrifluoride-ethylamines, (mono-, di-, and triethylamine) charge-transfer complex in DMSO was studied using fluorescence spectroscopy. The positive deviation from linearity has been observed in the Stern-Volmer plots. The experimental results showed that the fluorescence of carbazole was quenched by 2-chloro-3,5-dinitrobenzotrifluoride-ethylamines charge-transfer complex through a combined quenching procedure. The Stern-Volmer quenching constants, K(SV), have been determined and found to be greater quenching efficiency of ethylamine. Carbazole/2-chloro-3,5-dinitrobenzotrifluoride loaded PMMA film was exposed to ethylamine vapor, where the resulting absorption and emission changing properties were clearly monitored.
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Affiliation(s)
- Eun-Mi Lee
- BK21 FTIT Department of Advanced Organic Materials and Textile System Engineering, Chungnam National University, Daejeon 305-764, Republic of Korea
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34
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Longstaffe JG, Courtier-Murias D, Simpson AJ. The pH-dependence of organofluorine binding domain preference in dissolved humic acid. Chemosphere 2013; 90:270-275. [PMID: 22863060 DOI: 10.1016/j.chemosphere.2012.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 07/03/2012] [Accepted: 07/05/2012] [Indexed: 06/01/2023]
Abstract
In this study we explore the relationship between solution pH and the distribution of the binding interactions at different domains of a dissolved humic acid (HA) for three xenobiotics: pentafluoroaniline (PFA), pentafluorophenol (PFP), and hexafluorobenzene (HFB). The components of HA where xenobiotic interactions occur are identified using the (1)H{(19)F} Reverse Heteronuclear Saturation Transfer Difference (RHSTD) Nuclear Magnetic Resonance (NMR) spectroscopy experiment. At low pH, PFA and PFP interact preferentially with aromatic components of HA. Increasing pH reduces this preference. Conversely, HFB interacts with all components of HA equally, across the entire pH range. The possible roles of both aromatic-specific interactions and conformational changes of HA behind these observations are explored. It is shown that T-oriented π-π interactions at π-electron accepting HA structures are slightly stronger for PFA and PFP than for HFB. Using DOSY NMR it is shown that the pH-dependence of the interactions is correlated with changes in the conformation of the carbohydrate components of HA rather than with the aromatic components. It is argued that the observed preference for aromatic HA is caused by restricted access to the non-aromatic components of HA at low pH. These HA components form tightly bound hydrophobic domains due to strong inter- and intra-molecular hydrogen bonds. At high pH, these structures open up, making them more available for interactions with polar compounds.
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Affiliation(s)
- James G Longstaffe
- Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario, Canada M1C 1A4.
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35
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Li R, Ward JW, Smilgies DM, Payne MM, Anthony JE, Jurchescu OD, Amassian A. Direct structural mapping of organic field-effect transistors reveals bottlenecks to carrier transport. Adv Mater 2012; 24:5553-5517. [PMID: 22887742 DOI: 10.1002/adma.201201856] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 07/13/2012] [Indexed: 06/01/2023]
Affiliation(s)
- Ruipeng Li
- King Abdullah University of Science and Technology, Division of Physical Science and Engineering, Thuwal 23955-6900, Saudi Arabia
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36
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Zhang L, Dong C, Cheng M, Hu L, Du Y, Zhu Q, Zhang C. Resonance-enhanced two-photon ionization spectroscopy and theoretical calculations of 3,5-difluoroanisole and its Ar-containing complex. Spectrochim Acta A Mol Biomol Spectrosc 2012; 96:578-585. [PMID: 22864393 DOI: 10.1016/j.saa.2012.07.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 06/26/2012] [Accepted: 07/05/2012] [Indexed: 06/01/2023]
Abstract
The structure and vibrations of 3,5-difluoroanisole (3,5-DFA) in the first electronically excited (S(1)) state were studied by mass-analyzed resonant two-photon ionization (R2PI) technique as well as the quantum chemical calculations. The ab initio and density functional theory (DFT) calculations reveal that only one structure is stable for each of the S(0), S(1), and D(0) states. In the one color R2PI spectrum, the band origin of the S(1)←S(0) electronic transition (0(0) band) of 3,5-DFA is found to be 37,595±3 cm(-1). In the S(1) state, most of the bands observed are related to the in-plane ring deformation and out-of-plane bending vibrations. The adiabatic ionization energy (IE) of 3,5-DFA is determined to be 70,096±15 cm(-1) by the two color R2PI technique, in agreement with the values predicted by the DFT approaches. The dihalogen-substitution effects on the molecular structure, vibrational frequencies, and electronic transition and ionization energies were discussed in detail. The van der Waals complex of 3,5-DFA with argon (3,5-DFA···Ar) was also observed and studied. The 0(0) band of 3,5-DFA···Ar complex is red-shifted by about 9 cm(-1) with respect to that of 3,5-DFA. Both the experimental data and the calculated results indicate that the formation of 3,5-DFA···Ar complex gives only a weak influence on the properties of 3,5-DFA moiety.
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Affiliation(s)
- Lijuan Zhang
- Beijing National Laboratory of Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China
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Azzam W, Bashir A, Biedermann PU, Rohwerder M. Formation of highly ordered and orientated gold islands: effect of immersion time on the molecular adlayer structure of pentafluorobenzenethiols (PFBT) SAMs on Au(111). Langmuir 2012; 28:10192-10208. [PMID: 22690878 DOI: 10.1021/la301601c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Self-assembled monolayers (SAMs) of pentafluorobenzenethiol (PFBT) on Au(111) substrates, prepared with different immersion times (ITs) at room temperature, were studied using scanning tunneling microscopy (STM) and infrared reflection-absorption spectroscopy (IRRAS). In the present study, the focus was on several important points of interest in the field of SAMs. First, the gold islands formed upon adsorption of PFBT molecules on the gold surface were monitored at different ITs in terms of their size, density, and shape. After short ITs (5 to 30 min), small gold islands with rounded shape were formed. These gold islands were arranged in a rather regular fashion and found to be quite mobile under the influence of the STM-tip during the scanning. When the IT was increased to 16 h, the results revealed the formation of highly ordered and orientated gold islands with very unusual shapes with straight edges meeting at 60° or 120° running preferentially along the [11(-)0] substrate directions. The density of the gold islands was found to decrease with increasing IT until they almost disappeared from the SAMs prepared after 190 h of IT. On top of the gold islands, the PFBT molecules were found to adopt the closely packed (10√3 × 2) structure. Second, a number of structural defects such as disordered regions at the domain boundaries and dark row(s) of molecules within the ordered domains of the PFBT SAMs were observed at different ITs. The SAMs prepared after 190 h of IT were found to be free of these defects. Third, at low and moderate ITs, a variation in the PFBT molecular contrast was observed. This contrast variation was found to depend mainly on the tunneling parameters. Finally, our results revealed that the organization process of PFBT SAMs is IT-dependent. Consequently, a series of structural phases, namely, α, β, γ, δ, and ε were found. The α-, β-, γ-, and δ-phases were typically accompanied by the ε-phase that appeared on top of gold islands. With increasing IT, the α→β→ γ→δ→ε phase transitions took place. The resulting ε-phase, which covered the entire gold surface after 190 h of IT, yielded well-ordered self-assembled monolayers with large domains having a (10√3 × 2) superlattice structure.
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Ueyama J, Saito I, Kondo T, Taki T, Kimata A, Saito S, Ito Y, Murata K, Iwata T, Gotoh M, Shibata E, Wakusawa S, Kamijima M. Urinary concentrations of organophosphorus insecticide metabolites in Japanese workers. Chemosphere 2012; 87:1403-1409. [PMID: 22455950 DOI: 10.1016/j.chemosphere.2012.02.048] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 02/13/2012] [Accepted: 02/17/2012] [Indexed: 05/31/2023]
Abstract
A recent development in analytical chemistry has enabled us to monitor systemic organophosphorus insecticide (OP) exposure at individual levels. At present, however, limited data are currently available on urinary OP metabolite levels worldwide. The purpose of this study was to assess urinary dialkylphosphate (DAP) concentrations in Japanese workers. Urine samples were collected in both summer and winter from 339 Japanese adults who worked as food distributors (FDs, n=164), apple farmers (AFs, n=147) and pest control operators (PCOs, n=28). DAPs were measured by gas chromatography-mass spectrometry after derivatization with pentafluorobenzylbromide. Dimethylphosphate (DMP), diethylphosphate (DEP), dimethylthiophosphate (DMTP) and diethylthiophosphate (DETP) were detected in the urine of over 87% of the studied populations in both seasons. The geometric mean values of total DAPs (nmol g(-1) creatinine), DMP, DMTP, DEP and DETP (μg g(-1) creatinine) in summer and winter were 106.7 and 98.3, 7.0 and 3.8, 3.4 and 4.5, 0.8 and 1.5, and 0.3 and 0.2 for the FDs, 440.8 and 197.7, 33.1 and 10.8, 10.1 and 5.8, 4.2 and 4.7 and 1.6 and 0.8 for the AFs, and 473.4 and 284.6, 28.9 and 22.2, 17.6 and 4.6, 3.5 and 4.4, and 0.5 and 0.6 for the PCOs, respectively, thereby revealing significantly higher concentrations in AFs and PCOs groups than in the FDs in both seasons except for winter DMTP. These DAP concentrations were approximately the same or at lower levels compared with those reported in the previous literature. This is one of the first studies to demonstrate urinary DAP concentrations in Japanese adults.
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Affiliation(s)
- Jun Ueyama
- Department of Medical Technology, Nagoya University School of Health Sciences, Nagoya 461-8673, Japan
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Ando D, Fukushima M, Fujisawa T, Katagi T. Metabolism of the insecticide metofluthrin in cabbage (Brassica oleracea). J Agric Food Chem 2012; 60:2607-2616. [PMID: 22224911 DOI: 10.1021/jf203903r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The metabolic fate of metofluthrin [2,3,5,6-tetrafluoro-4-(methoxymethyl)benzyl (E,Z)-(1R,3R)-2,2-dimethyl-3-(prop-1-enyl)cyclopropanecarboxylate] separately labeled with (14)C at the carbonyl carbon and the α-position of the 4-methoxymethylbenzyl ring was studied in cabbage ( Brassica oleracea ). An acetonitrile solution of (14)C-metofluthrin at 431 g ai ha(-1) was once applied topically to cabbage leaves at head-forming stage, and the plants were grown for up to 14 days. Each isomer of metofluthrin applied onto the leaf surface rapidly volatilized into the air and was scarcely translocated to the untreated portion. On the leaf surface, metofluthrin was primarily degraded through ozonolysis of the propenyl side chain to produce the secondary ozonide, which further decomposed to the corresponding aldehyde and carboxylic acid derivatives. In the leaf tissues, the 1R-trans-Z isomer was mainly metabolized to its dihydrodiol derivative probably via an epoxy intermediate followed by saccharide conjugation in parallel with the ester cleavage, whereas no specific metabolite was dominant for the 1R-trans-E isomer. Isomerization of metofluthrin at the cyclopropyl ring was negligible for both isomers. In this study, the chemical structure of each secondary ozonide derivative was fully elucidated by the various modes of liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy together with cochromatography with the synthetic standard, and their cis/trans configuration was examined by the nuclear Overhauser effect (NOE) difference NMR spectrum.
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Affiliation(s)
- Daisuke Ando
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd., Takarazuka, Hyogo, Japan.
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Yan Z, Tounge B, Caldwell GW. An unusual intramolecular transfer of the fluorobenzyl cation between two remote amidic nitrogen atoms induced by collision in the gas phase. Rapid Commun Mass Spectrom 2012; 26:49-60. [PMID: 22215578 DOI: 10.1002/rcm.5297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A highly unusual rearrangement in collision-induced dissociation mass spectrometry is reported that involves intramolecular transfer of the fluorobenzyl cation between two remote amidic nitrogen atoms separated by five chemical bonds. The same intramolecular transfer was also observed for two related analogs. It is postulated that the ionic reactions are initiated by protonation of the first amidic nitrogen, resulting in formation of the fluorobenzyl cation and a neutral partner that are maintained together in the gas phase by electrostatic interactions as an intermediate ion-neutral complex. In the ion-neutral complex, the nascent fluorobenzyl cation approaches geometrically to the second amidic nitrogen atom on the neutral partner, and subsequently forms a new C-N bond and an isomeric precursor ion as the charge is retained on the amidic nitrogen. The newly formed isomeric precursor ion eventually undergoes the final fragmentation by amide bond cleavage. Alternatively, the ionic reactions proceed through a direct intramolecular transfer mechanism by which the molecular ion adopts to a ring-like configuration in the gas phase, so that both the donor and recipient nitrogens are geometrically close to each other within a bonding distance to permit a direct transfer between two sites even though they are separated by multiple chemical bonds.
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Affiliation(s)
- Zhengyin Yan
- Division of Drug Discovery, Johnson & Johnson Pharmaceutical R&D, LLC, Spring House, PA 19477, USA.
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Mahadevan D, Periandy S, Karabacak M, Ramalingam S. FT-IR and FT-Raman, UV spectroscopic investigation of 1-bromo-3-fluorobenzene using DFT (B3LYP, B3PW91 and MPW91PW91) calculations. Spectrochim Acta A Mol Biomol Spectrosc 2011; 82:481-492. [PMID: 21840753 DOI: 10.1016/j.saa.2011.07.082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 07/14/2011] [Accepted: 07/24/2011] [Indexed: 05/31/2023]
Abstract
The FT-IR and FT-Raman spectra of 1-bromo-3-fluorobenzene (C(6)H(4)FBr) molecule have been recorded using Bruker IFS 66V spectrometer in the range of 4000-100 cm(-1). The molecular geometry and vibrational frequencies in the ground state are calculated using the DFT (B3LYP, B3PW91 and MPW91PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets. The computed values of frequencies are scaled using a suitable scale factor to yield good coherence with the observed values. The isotropic DFT (B3LYP, B3PW91 and MPW1PW91) analysis showed good agreement with the experimental observations. Comparison of the fundamental vibrational frequencies with calculated results by B3LYP methods. The complete data of this molecule provide the information for future development of substituted benzene. The influence of bromine and fluorine atom on the geometry of benzene and its normal modes of vibrations has also been discussed. A study on the electronic properties, such as absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, was performed by time dependent DFT (TD-DFT) approach. The electronic structure and the assignment of the absorption bands in the electronic spectra of steady compounds were discussed. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. On the basis of the thermodynamic properties of the title compound at different temperatures have been calculated in gas phase, revealing the correlations between standard heat capacities (C) standard entropies (S), standard enthalpy changes (H) and temperatures.
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Affiliation(s)
- D Mahadevan
- Department of Physics, E.S. College of Engineering & Technology,Villupuram, India
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Haloui A, Haloui E. rα Structures of partially oriented pentafluorobenzenes C6F5X (X = H, Cl, I) as determined from 19F NMR spectra with 13C satellites. Magn Reson Chem 2011; 49:717-724. [PMID: 21971998 DOI: 10.1002/mrc.2818] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 06/22/2011] [Accepted: 07/03/2011] [Indexed: 05/31/2023]
Abstract
The (19)F spectra with natural-abundance carbon-13 satellites of C(6)F(5)X (X = H, Cl or I) in ZLI 1695 liquid crystal were analysed. Excluding fluorine-fluorine dipolar coupling constants from the fitting, the vibrationally corrected structures of these molecules were derived and compared with those calculated at DFT/B3LYP level of theory with the aug-cc-pVTZ basis set. The results show that pentafluorobenzene did not exhibit noticeable distortion of the aromatic ring, while chloropentafluorobenzene and iodopentafluorobenzene molecules showed some deformations in their determined structures. Relative anisotropies of F-F couplings have been deduced with accuracy for C(6)F(5)H molecule. Due to uncertainties in structure determination of C(6)F(5)Cl and C(6)F(5)I molecules, it was not possible to obtain precise values for all the corresponding anisotropies. In addition, it was found that the orientation of these molecules in the solvent used can be qualitatively explained in terms of dispersion forces.
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Affiliation(s)
- Abir Haloui
- Department of Chemistry, Faculty of Sciences, Manar 2, 2092 Tunis, Tunisia.
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43
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Fu W, Nef C, Knopfmacher O, Tarasov A, Weiss M, Calame M, Schönenberger C. Graphene transistors are insensitive to pH changes in solution. Nano Lett 2011; 11:3597-600. [PMID: 21766793 DOI: 10.1021/nl201332c] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
We observe very small gate-voltage shifts in the transfer characteristic of as-prepared graphene field-effect transistors (GFETs) when the pH of the buffer is changed. This observation is in strong contrast to Si-based ion-sensitive FETs. The low gate-shift of a GFET can be further reduced if the graphene surface is covered with a hydrophobic fluorobenzene layer. If a thin Al-oxide layer is applied instead, the opposite happens. This suggests that clean graphene does not sense the chemical potential of protons. A GFET can therefore be used as a reference electrode in an aqueous electrolyte. Our finding sheds light on the large variety of pH-induced gate shifts that have been published for GFETs in the recent literature.
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Affiliation(s)
- Wangyang Fu
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
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44
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Karabacak M, Cinar Z, Cinar M. Structural and spectroscopic characterization of 2,3-difluorobenzoic acid and 2,4-difluorobenzoic acid with experimental techniques and quantum chemical calculations. Spectrochim Acta A Mol Biomol Spectrosc 2011; 79:1511-1519. [PMID: 21646044 DOI: 10.1016/j.saa.2011.05.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/09/2011] [Accepted: 05/11/2011] [Indexed: 05/30/2023]
Abstract
In this study, the molecular conformation, vibrational and electronic transition analysis of 2,3-difluorobenzoic acid and 2,4-difluorobenzoic acid (C7H4F2O2) were presented using experimental techniques (FT-IR, FT-Raman and UV) and quantum chemical calculations. FT-IR and FT-Raman spectra in solid state were recorded in the region 4000-400 cm(-1) and 4000-5 cm(-1), respectively. The UV absorption spectra of the compounds that dissolved in ethanol were recorded in the range of 200-800 nm. The structural properties of the molecules in the ground state were calculated using density functional theory (DFT) and second order Møller-Plesset perturbation theory (MP2) employing 6-311++G(d,p) basis set. Optimized structure of compounds was interpreted and compared with the earlier reported experimental values. The scaled vibrational wavenumbers were compared with experimental results. The complete assignments were performed on the basis of the experimental data and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. A study on the electronic properties, such as absorption wavelength, excitation energy, dipole moment and frontier molecular orbital energy, were performed by time dependent DFT (TD-DFT) approach. Based on the UV spectra and TD-DFT calculations, the electronic structure and the assignments of the absorption bands of steady compounds were discussed. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecules.
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Affiliation(s)
- Mehmet Karabacak
- Department of Physics, Afyon Kocatepe University, 03040 Afyonkarahisar, Turkey.
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Nazimek T, Wasak M, Zgrajka W, Turski WA. Content of transfluthrin in indoor air during the use of electro-vaporizers. Ann Agric Environ Med 2011; 18:85-88. [PMID: 21736273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The quality of indoor air evokes increasing interest; however, no standards have been developed which determine the content of pesticides in the air of living space. At present, insecticides are increasingly more frequently applied to control household pests, flies, mosquitoes, termites and other harmful insects. In this study, the content of transfluthrin was measured indoors after the application of two consumer products containing this active substance, using commercially available electro-vaporizers. It was found that during the application of insecticides in the form of gel and liquid the mean concentration of transfluthrin in the air was 1.295-2.422 ug/m(3) and 3.817-5.227 ug/m(3), respectively. The concentration of an active agent in the air did not depend on the day of application. The concentration of transfluthrin was higher when used in the form of a liquid than a gel preparation. 18-24 hours after the discontinuation of the use of the preparation no active agent was found in the air. As long as the standards are developed regulating the content of insecticides in the air of living spaces and utility rooms, the most important method of preventing their potential hazardous effect is informing the users of these preparations about the occurrence of active substances in indoor air, and eventual risk of exposure to the effect of pesticides during their application at home.
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Affiliation(s)
- Teresa Nazimek
- Department of Toxicology, Institute of Rural Health, Lublin, Poland
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Chun JH, Lu S, Lee YS, Pike VW. Fast and high-yield microreactor syntheses of ortho-substituted [(18)F]fluoroarenes from reactions of [(18)F]fluoride ion with diaryliodonium salts. J Org Chem 2010; 75:3332-8. [PMID: 20361793 PMCID: PMC2891105 DOI: 10.1021/jo100361d] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A microreactor was applied to produce ortho-substituted [(18)F]fluoroarenes from the reactions of cyclotron-produced [(18)F]fluoride ion (t(1/2) = 109.7 min) with diaryliodonium salts. The microreactor provided a very convenient means for running sequential reactions rapidly with small amounts of reagents under well-controlled conditions, thereby allowing reaction kinetics to be followed and Arrhenius activation energies (E(a)) to be measured. Prepared symmetrical iodonium chlorides (Ar(2)I(+)Cl(-)) rapidly (<4 min) gave moderate (Ar = 2-MeOC(6)H(4), 51%) to high (Ar = Ph or 2-MeC(6)H(4), 85%) decay-corrected radiochemical yields (RCYs) of a single radioactive product (Ar(18)F). Reaction velocity with respect to Ar group was 2-MeOC(6)H(4) < Ph < 2-MeC(6)H(4). Activation energies were in the range 18-28 kcal/mol. Prepared unsymmetrical salts (e.g., 2-RC(6)H(4)I(+)2'-R'C(6)H(4)X(-); X = Cl or OTs) also rapidly gave two products (2-RC(6)H(4)(18)F and 2-R'C(6)H(4)(18)F) in generally high total RCYs (79-93%). Selectivity for product [(18)F]fluoroarene was controlled by the nature of the ortho substituents. The power of ortho substituents to impart an ortho-effect was in the following order:, 2,6-di-Me > 2,4,6-tri-Me > Br > Me > Et approximately (i)Pr >> H > OMe. For (2-methyphenyl)(phenyl)iodonium chloride, the time-course of reaction product selectivity was constant and consistent with the operation of the Curtin-Hammett principle. These results will aid in the design of diaryliodonium salt precursors to (18)F-labeled tracers for molecular imaging.
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Affiliation(s)
- Joong-Hyun Chun
- PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, Rm. B3 C346A, Building 10, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | - Shuiyu Lu
- PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, Rm. B3 C346A, Building 10, 10 Center Drive, Bethesda, MD 20892-1003, USA
| | - Yong-Sok Lee
- Center for Molecular Modeling, Center for Information Technology, NIH, Bethesda, MD 20892, USA
| | - Victor W. Pike
- PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, Rm. B3 C346A, Building 10, 10 Center Drive, Bethesda, MD 20892-1003, USA
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Alkorta I, Blanco F, Del Bene JE, Elguero J, Hernández-Folgado L, Jimeno ML. Difluorobenzenes revisited: an experimental and theoretical study of spin-spin coupling constants for 1,2-, 1,3-, and 1,4-difluorobenzene. Magn Reson Chem 2010; 48:68-73. [PMID: 19941318 DOI: 10.1002/mrc.2543] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The experimental spin-spin coupling constants (SSCCs) for 1,3- and 1,4-difluorobenzene have been determined anew, and found to be consistent with previously determined values. SSCCs for 1,2-, 1,3-, and 1,4-difluorobenzene have been analyzed by comparing them with the coupling constants computed using the second-order polarization propagator approximation (SOPPA) and the equation-of-motion coupled cluster singles and doubles method (EOM-CCSD). Eighty experimental values have been analyzed using SOPPA calculations, and a subset of 40 values using both SOPPA and EOM-CCSD approaches. One-bond coupling constants (1)J(C-C) and (1)J(C-F) are better described by EOM-CCSD, whereas one-bond (1)J(C-H) values are better described by SOPPA. An empirical equation is presented which allows for the prediction of unknown coupling constants from computed SOPPA values. A similar approach may prove useful for predicting coupling constants in larger systems.
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Affiliation(s)
- Ibon Alkorta
- Instituto de Química Médica (CSIC), Juan de la Cierva, 3, E-28006 Madrid, Spain.
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Qian K, Tang T, Shi T, Li P, Li J, Cao Y. Solid-phase extraction and residue determination of glyphosate in apple by ion-pairing reverse-phase liquid chromatography with pre-column derivatization. J Sep Sci 2009; 32:2394-400. [PMID: 19551741 DOI: 10.1002/jssc.200900118] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
A new method for glyphosate residue determination in apple has been developed. A SPE cartridge was used to clean up the samples before derivatization. Glyphosate was derivatized with 4-chloro-3,5-dinitrobenzotrifluoride (CNBF) and quantified by reverse ion-pair liquid chromatography using cetyltrimethylammonium bromide (CTAB) as ion-pair reagent. In pH 9.5 H(3)BO(3)-Na(2)B(4)O(7) medium, the reaction of glyphosate with CNBF was complete after 30 min at 60 degrees C. The stability of the derivative on exposure to light at room temperature in methanol-water was demonstrated. The labeled glyphosate was separated on a Kromasil C(18) column (250 x 4.6 mm, 5 microm) at room temperature and UV detection was applied at 360 nm. Separation was achieved within 15 min in gradient elution mode. The correlation coefficient for the method was 0.9998 at concentrations ranging from 0.1 to 50 microg/g. The calculated recoveries for glyphosate in apple were from 86.00 to 99.55%, and the relative standard deviations (n = 6) were from 1.43 to 6.32. The limit of detection was 0.01 microg/g for glyphosate in apple.
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Affiliation(s)
- Kun Qian
- College of Agriculture and Biotechnology, China Agricultural University, Beijing, China
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50
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Sun Y, Liu PF, Wang D, Li JQ, Cao YS. Determination of amitrole in environmental water samples with precolumn derivatization by high-performance liquid chromatography. J Agric Food Chem 2009; 57:4540-4544. [PMID: 19425574 DOI: 10.1021/jf900601f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Amitrole is a nonselective polar herbicide that can easily pollute ground and surface waters because of its high solubility in water. A precolumn derivatization high-performance liquid chromatographic method for amitrole analysis has been developed. Derivatization of amitrole was performed with 4-chloro-3,5-dinitrobenzotrifluoride (CNBF). The derivatization conditions and the influence of elution composition on the separation were investigated. In pH 9.5 H(3)BO(3)-Na(2)B(4)O(7) media, the reaction of amitrole with CNBF was complete at 60 degrees C after 30 min. The stability of the derivative under light irradiation and room temperature in methanol-water samples was demonstrated. The derivatized amitrole was separated on a K C(18) column (250 mm x 4.6 mm, 5 microm) at room temperature, and UV detection was applied at 360 nm. The separation of derivatized amitrole was achieved within 18 min by gradient elution mode. The method correlation coefficient was 0.9995, in concentrations ranging from 1.59 to 318 mg L(-1). The detection limit of amitrole was 0.16 mg L(-1) with a signal-to-noise ratio of 3. The proposed method was applied to the quantitative determination of amitrole in environmental water with recoveries of 92.0-103.0% and RSDs of 2.22-6.26, depending on the sample investigated. This method has good accuracy and repeatability that can be used to quantify amitrole in environmental water.
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Affiliation(s)
- Yan Sun
- College of Agriculture and Biotechnology, China Agricultural University, Beijing, China
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