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Kajtár M, Király SB, Bényei A, Kiss-Szikszai A, Kónya-Ábrahám A, Zhang N, Horváth LB, Bősze S, Li D, Kotschy A, Paczal A, Kurtán T. Competing Domino Knoevenagel-Cyclization Sequences with N-Arylcinnamylamines. J Org Chem 2024; 89:6937-6950. [PMID: 38691817 DOI: 10.1021/acs.joc.4c00299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Domino Knoevenagel-cyclization reactions of N-arylcinnamylamines were carried out with active methylene reagents, which took place with five competing cyclization mechanisms: intramolecular hetero Diels-Alder reaction, stepwise polar [2 + 2] cycloaddition, styryl or aza-Diels-Alder reactions followed by rearomatization, and [1,5]-hydride shift-6-endo cyclization. In the stepwise aza-Diels-Alder reaction, the N-vinylpyridinium moiety acted as an azadiene, producing a condensed heterocycle with tetrahydroquinolizinium and tetrahydroquiniline subunits. Antiproliferative activity with low micromolar IC50 values was identified for some of the novel scaffolds.
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Affiliation(s)
- Mihály Kajtár
- Department of Organic Chemistry, University of Debrecen, Debrecen 4002, Hungary
- Doctoral School of Chemistry, University of Debrecen, Egyetem square 1, 4032 Debrecen, Hungary
| | | | - Attila Bényei
- Department of Physical Chemistry, University of Debrecen, Debrecen 4002, Hungary
| | | | - Anita Kónya-Ábrahám
- Department of Organic Chemistry, University of Debrecen, Debrecen 4002, Hungary
| | - Ning Zhang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Lilla Borbála Horváth
- Hungarian Research Network (HUN-REN), Research Group of Peptide Chemistry, Eötvös Loránd University, H1117 Budapest, Hungary
| | - Szilvia Bősze
- Hungarian Research Network (HUN-REN), Research Group of Peptide Chemistry, Eötvös Loránd University, H1117 Budapest, Hungary
| | - Dehai Li
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, People's Republic of China
| | - Andras Kotschy
- Servier Research Institute of Medicinal Chemistry, Budapest 1031, Hungary
| | - Attila Paczal
- Servier Research Institute of Medicinal Chemistry, Budapest 1031, Hungary
| | - Tibor Kurtán
- Department of Organic Chemistry, University of Debrecen, Debrecen 4002, Hungary
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2
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Dobrikov GM, Nikolova Y, Slavchev I, Dangalov M, Deneva V, Antonov L, Vassilev NG. Structure and Conformational Mobility of OLED-Relevant 1,3,5-Triazine Derivatives. Molecules 2023; 28:molecules28031248. [PMID: 36770913 PMCID: PMC9921695 DOI: 10.3390/molecules28031248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
A series of OLED-relevant compounds, consisting of 1,3,5-triazine core linked to various aromatic arms by amino group, has been synthesized and characterized. The studied compounds exist in solution as a mixture of two conformers, a symmetric propeller and asymmetric conformer, in which one of the aromatic arms is rotated around the C-N bond. At temperatures below -40 °C, the VT NMR spectra in DMF-d7 are in a slow exchange regime, and the signals of two conformers can be elucidated. At temperatures above 100 °C, the VT NMR spectra in DMSO-d6 are in a fast exchange regime, and the averaged spectra can be measured. The ratio of symmetric and asymmetric conformers in DMF-d7 varies from 14:86 to 50:50 depending on the substituents. The rotational barriers of symmetric and asymmetric conformers in DMF-d7 were measured for all compounds and are in the interval from 11.7 to 14.7 kcal/mol. The ground-state energy landscapes of the studied compounds, obtained by DFT calculations, show good agreement with the experimental rotational barriers. The DFT calculations reveal that the observed chemical exchange occurs by the rotation around the C(1,3,5-triazine)-N bond. Although some of the compounds are potentially tautomeric, the measured absorption and emission spectra do not indicate proton transfer neither in the ground nor in the excited state.
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Affiliation(s)
- Georgi M. Dobrikov
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113 Sofia, Bulgaria
| | - Yana Nikolova
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113 Sofia, Bulgaria
| | - Ivaylo Slavchev
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113 Sofia, Bulgaria
| | - Miroslav Dangalov
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113 Sofia, Bulgaria
| | - Vera Deneva
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113 Sofia, Bulgaria
- Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
| | - Liudmil Antonov
- Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
| | - Nikolay G. Vassilev
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 9, 1113 Sofia, Bulgaria
- Correspondence:
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3
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Ilgen J, Nowag J, Kaltschnee L, Schmidts V, Thiele CM. Gradient selected pure shift EASY-ROESY techniques facilitate the quantitative measurement of 1H, 1H-distance restraints in congested spectral regions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 324:106900. [PMID: 33503522 DOI: 10.1016/j.jmr.2020.106900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/22/2020] [Indexed: 06/12/2023]
Abstract
For elucidating molecular structure and dynamics in solution, NMR experiments such as NOESY, ROESY and EXSY have been used excessively over the past decades, to provide interatomic distance restraints or rates for chemical exchange. The extraction of such information, however, is often prohibited by signal overlap in these spectra. To reduce this problem, pure shift methods for improving the spectral resolution have become popular. We report on pure shift EASY-ROESY experiments and their application to extract cross-relaxation rates, proton-proton distances and exchange rates. Homonuclear decoupling (pure shift) is applied in the indirect dimension using the PSYCHE or the perfectBASH technique, to enhance the spectral resolution of severely overcrowded spectral regions. The spectral quality is further improved by using a gradient selected F1-PSYCHE-EASY-ROESY, which produces significantly less t1-noise than the experiment used previously, as also demonstrated by employing the recently introduced SAN (signal-artefact-noise) plots. Applications include the quantification of distance restraints in a peptide organocatalyst and the extraction of a number of distance restraints in cyclosporine A, which were previously not available for analysis, because they were either located in overcrowded spectral regions or hidden under t1-noise. Distances extracted and exchange rates obtained are accurate. Also, the 2D gradient-selected F1-perfectBASH-EASY-ROESY with the additional gradient selection proposed herein, which is superior in terms of sensitivity, can be used to accurately quantify cross-relaxation.
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Affiliation(s)
- Julian Ilgen
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 16, D-64287 Darmstadt, Germany
| | - Jens Nowag
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 16, D-64287 Darmstadt, Germany
| | - Lukas Kaltschnee
- Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg 11, 37077 Göttingen, Germany; Center for Biostructural Imaging of Neurodegeneration (BIN), Von-Siebold-Str. 3a, 37075 Göttingen, Germany
| | - Volker Schmidts
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 16, D-64287 Darmstadt, Germany
| | - Christina M Thiele
- Clemens-Schöpf-Institut für Organische Chemie und Biochemie, Technische Universität Darmstadt, Alarich-Weiss-Straße 16, D-64287 Darmstadt, Germany.
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Kánya N, Kun S, Batta G, Somsák L. Glycosylation with ulosonates under Mitsunobu conditions: scope and limitations. NEW J CHEM 2020. [DOI: 10.1039/d0nj03044a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mitsunobu reactions on highly hindered tertiary type hydroxy groups of ulosonates: from 47 NuH compounds O-, N-, and S-nucleophiles gave the corresponding ulosidonates in 30–78% yields, while C-nucleophiles were unreactive.
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Affiliation(s)
- Nándor Kánya
- Department of Organic Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
| | - Sándor Kun
- Department of Organic Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
| | - Gyula Batta
- Department of Organic Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
| | - László Somsák
- Department of Organic Chemistry
- University of Debrecen
- H-4002 Debrecen
- Hungary
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5
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Synthesis and Structure-Activity relationship of 1-(5-isoquinolinesulfonyl)piperazine analogues as inhibitors of Mycobacterium tuberculosis IMPDH. Eur J Med Chem 2019; 174:309-329. [PMID: 31055147 PMCID: PMC6990405 DOI: 10.1016/j.ejmech.2019.04.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 04/11/2019] [Accepted: 04/11/2019] [Indexed: 02/06/2023]
Abstract
Tuberculosis (TB) is a major infectious disease associated increasingly with drug resistance. Thus, new anti-tubercular agents with novel mechanisms of action are urgently required for the treatment of drug-resistant TB. In prior work, we identified compound 1 (cyclohexyl(4-(isoquinolin-5-ylsulfonyl)piperazin-1-yl)methanone) and showed that its anti-tubercular activity is attributable to inhibition of inosine-5′-monophosphate dehydrogenase (IMPDH) in Mycobacterium tuberculosis. In the present study, we explored the structure–activity relationship around compound 1 by synthesizing and evaluating the inhibitory activity of analogues against M. tuberculosis IMPDH in biochemical and whole-cell assays. X-ray crystallography was performed to elucidate the mode of binding of selected analogues to IMPDH. We establish the importance of the cyclohexyl, piperazine and isoquinoline rings for activity, and report the identification of an analogue with IMPDH-selective activity against a mutant of M. tuberculosis that is highly resistant to compound 1. We also show that the nitrogen in urea analogues is required for anti-tubercular activity and identify benzylurea derivatives as promising inhibitors that warrant further investigation. Forty-eight analogues of 1-(5-isoquinolinesulfonyl)piperazine were synthesized. Biochemical, whole-cell, and X-ray studies were performed to elucidate the IMPDH inhibition. Piperazine and isoquinoline rings were essential for target-selective whole-cell activity. Compound 47 showed improved IC50 against the MtbIMPDH and maintained on-target whole-cell activity. Compound 21 showed activity against IMPDH in both wild type M. tuberculosis and a resistant mutant of compound 1.
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6
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Kicsák M, Mándi A, Varga S, Herczeg M, Batta G, Bényei A, Borbás A, Herczegh P. Tricyclanos: conformationally constrained nucleoside analogues with a new heterotricycle obtained from a d-ribofuranose unit. Org Biomol Chem 2019; 16:393-401. [PMID: 29090729 DOI: 10.1039/c7ob02296d] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A novel type of nucleoside analogue in which the sugar part is replaced by a new tricycle, 3,7,10-trioxa-11-azatricyclo[5.3.1.05,11]undecane has been prepared by substrate-controlled asymmetric synthesis. 1,5-Dialdehydes obtained from properly protected or unprotected uridine, ribothymidine, cytidine, inosine, adenosine and guanosine by metaperiodate oxidation reacted readily with tris(hydroxymethyl)aminomethane to provide the corresponding tricyclic derivatives with three new stereogenic centers. Through a double cyclisation cascade process the tricyclic compounds were obtained in good to high yields, with very high diastereoselectivity. Formation of one stereoisomer, out of the eight possible, was observed in all cases. The absolute configuration of the new stereotriad-containing tricyclic systems was aided by conventional NMR experiments followed by chemical shift calculations using an X-ray crystal structure as reference that was in good agreement with H-H distances obtained from a new ROESY NMR method. The synthesis was compatible with silyl, trityl and dimethoxytrityl protecting groups. A new reagent mixture containing ZnCl2, Et3SiH and hexafluoroisopropanol was developed for detritylation of the acid-sensitive tricyclano nucleosides.
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Affiliation(s)
- Máté Kicsák
- Department of Pharmaceutical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary.
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Parella T. Towards perfect NMR: Spin-echo versus perfect-echo building blocks. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2019; 57:13-29. [PMID: 29927497 DOI: 10.1002/mrc.4776] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/10/2018] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
The development of new tools to improve the quality of nuclear magnetic resonance (NMR) spectra is a challenging task. The concept of "perfect NMR" includes the design of robust pulse sequences that allow an investigator to obtain undistorted pure in-phase signals, with pure absorption lineshapes that are free of phase anomalies derived from undesired J modulations. Here, alternative NMR building blocks to the spin-echo that are based on a general double SE module, known as a perfect-echo, are reviewed. Several implementations to minimize/remove unwanted dispersive contributions in homonuclear and heteronuclear NMR experiments are described and illustrated with some examples of broad interest for small molecules.
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Affiliation(s)
- Teodor Parella
- Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, Barcelona, Catalonia, Spain
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8
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Gyöngyösi T, Timári I, Haller J, Koos MRM, Luy B, Kövér KE. Boosting the NMR Assignment of Carbohydrates with Clean In-Phase Correlation Experiments. Chempluschem 2018; 83:53-60. [PMID: 31957316 DOI: 10.1002/cplu.201700452] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/18/2017] [Indexed: 12/12/2022]
Abstract
Novel CLIP-COSY based homo- and heteronuclear correlation experiments are reported for the rapid, semi-automated NMR assignment of small to medium-sized molecules. The homonuclear CLIP-COSY and corresponding relayed experiments employ the perfect-echo based mixing sequence for in-phase coherence transfer between directly and/or indirectly coupled proton spins. The combined analysis of the resulting CLIP-COSY and relayed spectra made it possible to easily track down, layer by layer, the proton-proton connectivity network. In larger molecules the narrow chemical shift range of protons may, however, compromise the efficacy of the homonuclear correlation based assignment strategy. To overcome this limitation, an HSQC variant of the CLIP-COSY experiment has now been devised. Combined treatment of HSQC-CLIP-COSY (relayed) and standard HSQC spectra facilitates simultaneous and semi-automatic assignment of 1 H and 13 C resonances of medium-sized molecules, such as pentasaccharides. The recently introduced PSYCHE broadband homonuclear decoupling scheme has been also implemented into the devised homo- and heteronuclear CLIP-COSY based experiments, resulting in fully decoupled high-resolution pure-shift correlation spectra.
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Affiliation(s)
- Tamás Gyöngyösi
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
| | - István Timári
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary.,Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Jens Haller
- Institute of Organic Chemistry, and Institute for Biological Interfaces 4-Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Martin R M Koos
- Institute of Organic Chemistry, and Institute for Biological Interfaces 4-Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Burkhard Luy
- Institute of Organic Chemistry, and Institute for Biological Interfaces 4-Magnetic Resonance, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany
| | - Katalin E Kövér
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen, 4032, Hungary
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Boros S, Gáspári Z, Batta G. Accurate NMR Determinations of Proton–Proton Distances. ANNUAL REPORTS ON NMR SPECTROSCOPY 2018:1-39. [DOI: 10.1016/bs.arnmr.2017.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
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10
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Abstract
Structure, conformation, and dynamics of sphingolipids can provide substantial help in better understanding sphingolipid-ligand interaction mechanisms. Both the oligosaccharide structure and the ceramide moiety of native glycosphingolipid can be established directly by NMR spectroscopic analysis without the necessity to resort to any other chemical or spectroscopic methods. NMR is a powerful technique to investigate interaction between small ligand, such as ganglioside, and membrane protein.
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Affiliation(s)
- Domenico Acquotti
- Centro Interdipartimentale Misure, University of Parma, Parma, Italy.
| | - Laura Mauri
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Sandro Sonnino
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
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Lázár L, Juhász L, Batta G, Borbás A, Somsák L. Unprecedented β-manno type thiodisaccharides with a C-glycosylic function by photoinitiated hydrothiolation of 1-C-substituted glycals. NEW J CHEM 2017. [DOI: 10.1039/c6nj03751h] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Unique thiodisaccharides of β-manno type featuring C-glycosylic structure with an anomeric functional group for further elaboration were obtained by radical-mediated hydrothiolation of 1-C-acceptor-substituted glycals.
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Affiliation(s)
- László Lázár
- Department of Organic Chemistry
- University of Debrecen
- Hungary
| | - László Juhász
- Department of Organic Chemistry
- University of Debrecen
- Hungary
| | - Gyula Batta
- Department of Organic Chemistry
- University of Debrecen
- Hungary
| | - Anikó Borbás
- Department of Pharmaceutical Chemistry
- University of Debrecen
- Hungary
| | - László Somsák
- Department of Organic Chemistry
- University of Debrecen
- Hungary
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