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Synthesis of 2,2’-Bipyridines via Dehydrogenative Dimerization of Pyridines Using Sodium Dispersion. Synlett 2023. [DOI: 10.1055/a-2047-8355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
2,2’-Bipyridine derivatives were synthesized by dehydrogenative dimerization of non-activated pyridines using sodium dispersion. The reaction features operational simplicity, mild conditions, and the use of earth abundant and non-toxic sodium as the sole metal source. Importantly, transition metals are not required, which is beneficial in the fields of materials science and drug synthesis, where the contamination of the transition metals may cause significant problems.
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2
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Abstract
In the presence of triphenylphosphine as a mild reductant, the use of catalytic amounts of Mo(CO)6 and an ortho-quinone ligand enables the intermolecular reductive coupling of aromatic aldehydes and the intramolecular coupling of aromatic ketones to produce functionalized alkenes. Diaryl- and diheteroaryl alkenes are synthesized with high (E)-selectivity and a tolerance toward bromide, iodide, and steric hindrance. Intramolecular coupling of dicarbonyl compounds under similar conditions affords mono- and disubstituted phenanthrenes.
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3
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A Transmetallation Pathway to a Dinuclear Chromium μ-Methylene Complex. CHEM LETT 2022. [DOI: 10.1246/cl.220075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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4
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5
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Regiodivergent Carbene/Alkyne Metathesis in Chromium-Mediated Coupling and Cyclization with 1,6-Enynes. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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6
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Correction to "Isolation and Structural Characterization of Geminal Di(iodozincio)methane Complexes Stabilized with Nitrogen Ligands". J Am Chem Soc 2021; 143:20524. [PMID: 34823357 DOI: 10.1021/jacs.1c10680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Abstract
Carbon tetrabromide can be reduced with CrBr2 in THF to form a dinuclear carbido complex, [CrBr2(thf)2)][CrBr2(thf)3](μ-C), along with formation of [CrBr3(thf)3]. An X-ray diffraction (XRD) study of the pyridine adduct displayed a dinuclear structure bridged by a carbido ligand between 5- and 6-coordinate chromium centers. The carbido complex reacted with two equivalents of aldehydes to form α,β-unsaturated ketones. Treatment of the carbido complex with alkenes resulted in a formal double-cyclopropanation of alkenes by the carbido moiety to afford spiropentanes. Isotope labeling studies using a 13C-enriched carbido complex, [CrBr2(thf)2)][CrBr2(thf)3](μ-13C), identified that the quaternary carbon in the spiropentane framework was delivered by carbide transfer from the carbido complex. Terminal and internal alkynes also reacted with the carbido complex to form cyclopropenylidene complexes. A solid-state structure of the diethylcyclopropenylidene complex, prepared from 3-hexyne, showed a mononuclear cyclopropenylidene chromium(iii) structure.
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8
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Long range interactions and related carbon-carbon bond reconstruction between interior and surface defects in nanodiamonds. Phys Chem Chem Phys 2021; 23:14592-14600. [PMID: 34164634 DOI: 10.1039/d0cp05914e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Interactions between interior substitutional nitrogen defects and surface unsaturated dangling bonds in synthetic nanodiamonds of ∼25 nm size were explored experimentally and theoretically. The experimental results demonstrate the disappearance of the specific paramagnetism of nitrogen centers in the smallest nanoparticles isolated after processing large micron diamonds in a ball mill, accompanied by the formation of unsaturated surface dangling bonds and internal defects. First principles modelling confirms the vanishing of the magnetic moments related with nitrogen centers even for distances from the surface defects greater than 1 nm. To understand this effect, we consider a bond reconstruction scheme with the formation of several carbon-carbon double bonds in the area between the interior and surface point defects. The scheme is in agreement with the changes in electron density through the distance between the two defects. The developed approach can be used to describe the interactions between various defects in carbon-based systems.
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Abstract
Reduction of CCl4 by CrCl2 in THF afforded a trinuclear chromium(iii) carbyne [CrCl(thf)2]3(μ3-CCl)(μ-Cl)3. The chlorocarbyne complex reacted with aldehydes to afford chloroallylic alcohols and terminal alkynes. The mechanistic study proposed two competitive pathways via an α-chlorovinyl intermediate.
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Molybdenum‐Catalyzed Deoxygenative Cyclization of Carbonyl Compounds for the Synthesis of Pyrido[2,1‐
a
]isoindoles. ASIAN J ORG CHEM 2021. [DOI: 10.1002/ajoc.202100038] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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11
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Structural elucidation of a methylenation reagent of esters: synthesis and reactivity of a dinuclear titanium(iii) methylene complex. Chem Sci 2021; 12:3509-3515. [PMID: 34163624 PMCID: PMC8179466 DOI: 10.1039/d0sc06366e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Transmetallation of a zinc methylene complex [ZnI(tmeda)]2(μ-CH2) with a titanium(iii) chloride [TiCl3(tmeda)(thf)] produced a titanium methylene complex. The X-ray diffraction study displayed a dinuclear methylene structure [TiCl(tmeda)]2(μ-CH2)(μ-Cl)2. Treatment of an ester with the titanium methylene complex resulted in methylenation of the ester carbonyl to form a vinyl ether. The titanium methylene complex also reacted with a terminal olefin, resulting in olefin-metathesis and olefin-homologation. Cyclopropanation by methylene transfer from the titanium methylene proceeded by use of a 1,3-diene. The mechanistic study of the cyclopropanation reaction by the density functional theory calculations was also reported. Transmetallation of a zinc methylene complex [ZnI(tmeda)]2(μ-CH2) with a titanium(iii) chloride [TiCl3(tmeda)(thf)] produced a titanium methylene complex.![]()
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Structure and Magnetic Properties of Superoxide Radical Anion Complexes with Low Binding Energy at the Graphene Edges. RUSS J COORD CHEM+ 2020. [DOI: 10.1134/s107032842011007x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Conduction gaps after pulmonary vein isolation due to high contact force ablation in patients with atrial fibrillation. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.0444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Catheter ablation for atrial fibrillation (AF) with high contact force (CF) has been reported to lead to the gaps after pulmonary vein isolation (PVI), and the appearance of the gaps depends on the site in the left atrium (LA).
Purpose
The aim of this study is to clarify the relationship between the gaps appearance and high CF.
Methods
In the clinical study, 74 consecutive patients (39 males, age 71±9, 46 with paroxysmal AF) underwent conventional PVI with a point-by-point radiofrequency (RF) ablation using a CF sensing catheter (TactiCath SETM). RF energy (J), number of RF point, Lesion index (LSI), force-time integral (FTI), average CF (g), and the degree of LA depression with high CF were evaluated. In the experimental study (figure), the relationship between the ablation area and the degree of depression with high CF using bovine left ventricular wall.
Results
In the clinical study, the gaps were found in 175 of 1182 sites after first path PVI ablation. The CF in the gap sites was higher than without the gap sites in RPV roof, anterior RSPV and anterior RPV carina (18.9±6.8 vs 15.0±5.7g p=0.0262, 26.4±11.6 vs 19.5±6.0g p=0.0029, 22.7±6.4 vs 19.1±5.5g, p=0.0161). Meanwhile, there were no differences in RF energy, number of RF point, LSI, FTI. High CF (≥30g) showed a depression of 3 mm or more in only RPV roof and anterior RPV (figure). In the experimental study, the ablation range narrowed as the indentation deepened with more than 30g CF (r=0.6417, p=0.0625).
Conclusion
Catheter ablation for AF with high contact force might lead to the gaps in RPV roof and anterior RPV site by the reduction of the ablation area due to depression caused by the pressure.
Extension of each contact force
Funding Acknowledgement
Type of funding source: None
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Cyclization of 5-alkynones with chromium alkylidene equivalents generated in situ from gem-dichromiomethanes. Chem Commun (Camb) 2020; 56:9711-9714. [PMID: 32700694 DOI: 10.1039/d0cc03986a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A rare example of cyclization with 5-alkynones, which possess non-polar alkynyl and less electrophilic polar keto carbonyl groups, was demonstrated. The key to promoting carbene/alkyne metathesis followed by alkylidenation with pendant C[double bond, length as m-dash]O double bonds was the Schrock-type nucleophilic reactivity of the generated chromium carbene equivalents from readily available diiodomethanes and CrCl2 by simple heating.
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Cyclization of 1,n-Enynes Initiated by the Addition Reaction of gem-Dichromiomethane Reagents to Alkynes. Org Lett 2020; 22:3985-3988. [DOI: 10.1021/acs.orglett.0c01304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Regioselective Sequential Silylation and Borylation of Aromatic Aldimines as a Strategy for Programming Synthesis of Multifunctionalized Benzene Derivatives. Org Lett 2020; 22:316-321. [PMID: 31850763 DOI: 10.1021/acs.orglett.9b04338] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Regioselective difunctionalization of two different C-H bonds in one pot using a three-component coupling reaction is described. The reaction order is important for controlling the reactivity and regioselectivity, and the first silylation promotes the second borylation. The introduced formyl, silyl, and boryl functional groups could be independently converted to other functional groups, and the substitution pattern for the resulting benzenes is difficult to access by conventional methods.
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17
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Correction: Cyclization of 5-alkynones with chromium alkylidene equivalents generated in situ from gem-dichromiomethanes. Chem Commun (Camb) 2020; 56:15593. [DOI: 10.1039/d0cc90516j] [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
Correction for ‘Cyclization of 5-alkynones with chromium alkylidene equivalents generated in situ from gem-dichromiomethanes’ by Masahito Murai et al., Chem. Commun., 2020, 56, 9711–9714, DOI: 10.1039/D0CC03986A.
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Mechanistic Insights into Rhenium-Catalyzed Regioselective C-Alkenylation of Phenols with Internal Alkynes. Chemistry 2019; 25:15189-15197. [PMID: 31532028 DOI: 10.1002/chem.201903910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/17/2019] [Indexed: 11/12/2022]
Abstract
A (μ-aryloxo)rhenium complex was isolated and confirmed as a key precatalyst for rhenium-catalyzed ortho-alkenylation (C-alkenylation) of unprotected phenols with alkynes. The reaction exclusively provided ortho-alkenylphenols; the formation of para or multiply alkenylated phenols and hydrophenoxylation (O-alkenylation) products was not observed. Several mechanistic experiments excluded a classical Friedel-Crafts-type mechanism, leading to the proposed phenolic hydroxyl group assisted electrophilic alkenylation as the most plausible reaction mechanism. For this purpose, the use of rhenium, a metal between the early and late transition metals in the periodic table, was key for the activation of both the soft carbon-carbon triple bond of the alkyne and the hard oxygen atom of the phenol, at the same time. ortho-Selective alkenylation with allenes also provided the corresponding adducts with a substitution pattern different from that obtained by the addition reaction with alkynes.
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Rhenium-Catalyzed Cyclization via 1,2-Iodine and 1,5-Hydrogen Migration for the Synthesis of 2-Iodo-1H-indenes. Org Lett 2019; 21:6756-6760. [DOI: 10.1021/acs.orglett.9b02380] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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20
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Deoxygenative Insertion of Carbonyl Carbon into a C(sp3)–H Bond: Synthesis of Indolines and Indoles. J Am Chem Soc 2019; 141:9832-9836. [DOI: 10.1021/jacs.9b05428] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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21
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Lithium‐Free Synthesis of Sodium 2,2,6,6‐Tetramethylpiperidide and Its Synthetic Applications. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900215] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Rhenium-Catalyzed Regioselective ortho-Alkenylation and [3 + 2 + 1] Cycloaddition of Phenols with Internal Alkynes. Org Lett 2019; 21:3441-3445. [PMID: 30998367 DOI: 10.1021/acs.orglett.9b01214] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
An operationally simple and direct rhenium-catalyzed ortho-alkenylation ( C-alkenylation) of unprotected phenols with alkynes was developed. The protocol provided ortho-alkenylphenols exclusively, and formation of para- or multiply alkenylated phenols and hydrophenoxylation ( O-alkenylation) products were not observed. The [3 + 2 + 1] cycloaddition of phenols and two alkynes via ortho-alkenylation was also demonstrated, in which the alkynes functioned as both two- and one-carbon units. These reactions proceeded with readily available starting materials under neutral conditions without additional ligands.
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Regioselective Functionalization of 9,9-Dimethyl-9-silafluorenes by Borylation, Bromination, and Nitration. J Org Chem 2019; 84:5667-5676. [PMID: 30938531 DOI: 10.1021/acs.joc.9b00598] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Despite the utility of 9-silafluorenes as functional materials and as building blocks, methods for efficient functionalization of their backbone are rare, probably because of the presence of easily cleavable C-Si bonds. Although controlling the regioselectivity of iridium-catalyzed direct borylation of C-H bonds is difficult, we found that bromination and nitration of 2-methoxy-9-silafluorene under mild conditions occurred predominantly at the electron-rich position. The resulting product having methoxy and bromo groups can be utilized as a building block for the synthesis of unsymmetrically substituted 9-silafluorene-containing π-conjugated molecules.
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Abstract
A stannyl-group-substituted gem-dichromiomethane species, generated in situ from CrCl2, TMEDA, and tributyl(diiodomethyl)stannane, worked as an efficient stannylcarbene equivalent to promote cyclopropanation of alkenes. The reaction provided synthetically useful stannylcyclopropanes directly from commercially available unactivated alkenes without using potentially flammable alkylzinc and diazo compounds. Structural characterization of stannyl- and germyl-group-substituted gem-dichromiomethane complexes and the effect of group 14 elements containing substituents for cyclopropanation are also described.
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Palladium-catalyzed double-bond migration of unsaturated hydrocarbons accelerated by tantalum chloride. Chem Commun (Camb) 2019; 55:2769-2772. [PMID: 30768079 DOI: 10.1039/c9cc00223e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The operationally simple palladium-catalyzed double-bond migration without heteroatom-containing coordinating functional groups is described. Addition of TaCl5 as a second catalyst greatly enhanced the migration efficiency to provide β-alkylstyrenes through migration of up to a five-carbon chain. Both catalysts were commercially available, and the reaction occurred without external ligands under neutral conditions. The reaction proceeded via generation of π-allyl palladium species, which enabled the chemoselective double-bond migration of hydrocarbons in the presence of allylethers. Remote functionalization through double-bond migration was also demonstrated using FeCl3 as a second catalyst.
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Abstract P5-12-17: Prognostic and predictive value of serum level of vascular endothelial growth factor-A in metastatic breast cancer patients treated with bevacizumab plus paclitaxel. Cancer Res 2019. [DOI: 10.1158/1538-7445.sabcs18-p5-12-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background
Several studies showed that first-line bevacizumab plus chemotherapy for HER2-negative metastatic breast cancer improves progression-free survival and tumor response rate but not overall survival. MERiDiAN trial evaluated plasma vascular endothelial growth factor-A (VEGF-A) prospectively as a predictive biomarker for bevacizumab efficacy in metastatic breast cancer. However, results of this trial do not support using baseline plasma VEGF-A to identify patients benefitting most from bevacizumab. We measured baseline serum VEGF-A level from stored blood samples of metastatic breast cancer patient with treated bevacizumab plus paclitaxel as fist-line and later line therapy, and evaluated a correlation between serum VEGF-A level and efficacy of bevacizumab and prognosis of breast cancer patients tread with bevacizumab, retrospectively.
Patients and methods
We examined blood samples from 57 metastatic breast cancer patients treated with bevacizumab and paclitaxel, after obtaining written informed consent. And, we evaluated a correlation between baseline serum VEGF-A level and time to treatment failure (TTF) and overall survival (OS). We also compared the serum VEGF-A level of response group (CR and PR) and that of non-response group (SD and PD).
Results
Baseline serum level of VEGF-A ranged from 80 to 2079 pg/ml. Cases of treatment line were as follows: first-line, 22 cases (38.6%); second line, 11 cases (19.3%) and third-line and the later line, 24 cases (42.1%). The cutoff identified by ROC curve analysis that was able to differentiate response group and non-response group in first-line setting was 360pg/ml for serum VEGF-A. And, we separated high serum VGEF-A group and low serum VEGF-A group of patients treated with bevacizumab plus paclitaxel.
In patients treated as first line therapy, median TTF was 4.0 months with high serum VGEF-A group versus 5.0 months with low serum VEGF-A group, and median OS was 12 months with high serum VGEF-A group versus 11months with low serum VEGF-A group. There were no significant differences in both TTF and OS in first line setting. In patients treated as second line and later line therapy, median TTF was 2.8 months with high serum VGEF-A group versus 7.1 months with low serum VEGF-A group, and median OS was 6.4 months with high serum VGEF-A group versus 12.7 months with low serum VEGF-A group. The prognosis of high serum VEGF-A group was significantly worse than that of low serum group in both TTF and OS.
The serum VEGF-A level of response group was tend to be higher than that of non-response group in first line setting, and was lower in second and later line setting. However, there were no significant differences.
Conclusion
In this study, serum VEGF-A cannot be a predictor for efficacy of bevacizumab plus paclitaxel as first line therapy for metastatic breast cancer patients. On the other hand, there was a possibility that high serum level of VEGF-A can be a poor prognostic factor in late line therapy setting of bevacizumab.
Citation Format: Tozuka K, Nagai SE, Matsumoto H, Hayashi Y, Kubo K, Tsuboi M, Sato A, Takai K, Wang X, Yamada Y, Inoue K. Prognostic and predictive value of serum level of vascular endothelial growth factor-A in metastatic breast cancer patients treated with bevacizumab plus paclitaxel [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-12-17.
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Regioselective arene homologation through rhenium-catalyzed deoxygenative aromatization of 7-oxabicyclo[2.2.1]hepta-2,5-dienes. Chem Commun (Camb) 2019; 55:2332-2335. [DOI: 10.1039/c9cc00270g] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A facile approach to PAHs with an arm-chair edge via regioselective bromination, Diels–Alder reaction, and rhenium-catalyzed deoxygenative aromatization is described.
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Unsymmetrical Difunctionalization of Two Different C–H Bonds in One Pot Under Transition-Metal Catalysis. SYNTHESIS-STUTTGART 2018. [DOI: 10.1055/s-0037-1611066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Recent advancements in unsymmetrical difunctionalization based on the substitution of two different C–H bonds in one-pot are described. Due to the difficulty of controlling reactivity and selectivity, multi-functionalization via substitution of several C–H bonds to install different functional groups has been limited until recently, in comparison with well-studied functionalization via sequential addition to unsaturated π-bonds. This difunctionalization protocol provides an efficient and rapid approach to a library of structurally complicated target molecules through the formation of multiple C–X bonds with high atom- and step-economy.1 Introduction2 ortho-Selective Functionalization of Two Different C–H Bonds
Relative to the Directing Group2.1 Unsymmetrical Difunctionalization with the Introduction of Similar Functional Groups2.2 Unsymmetrical Difunctionalization with the Introduction of Different Functional Groups2.3 ortho-Selective Unsymmetrical Difunctionalization Promoted by Two Different Directing Groups Appearing During the Progress of the Reaction3 ortho/meta-Selective C–H Bond Difunctionalization Relative to the Directing Group4 Sequential Difunctionalization of Fused Aromatic Compounds and Heterocycles5 Summary and Outlook
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Use of Cyclopropane as C1 Synthetic Unit by Directed Retro-Cyclopropanation with Ethylene Release. J Am Chem Soc 2018; 140:15425-15429. [DOI: 10.1021/jacs.8b09297] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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32
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Capturing the Crystal Structure of the Key Species! J SYN ORG CHEM JPN 2018. [DOI: 10.5059/yukigoseikyokaishi.76.640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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33
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Amine-Promoted anti-Markovnikov Addition of 1,3-Dicarbonyl Compounds with Terminal Alkynes under Rhenium Catalysis. ACS Catal 2018. [DOI: 10.1021/acscatal.8b01338] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Iridium-Catalyzed Sequential Silylation and Borylation of Heteroarenes Based on Regioselective C-H Bond Activation. Angew Chem Int Ed Engl 2018; 57:5843-5847. [PMID: 29573532 DOI: 10.1002/anie.201801229] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/06/2018] [Indexed: 12/30/2022]
Abstract
An iridium-catalyzed regioselective sequential silylation and borylation of heteroarenes was developed, which represents a rare example of unsymmetrical intermolecular C-H bond difunctionalization through the introduction of two different functionalities during a one-pot transformation. Although the substrate scope for the dehydrogenative silylation of heteroarenes has been limited mainly to electron-rich five-membered rings, the current reaction proceeds with both electron-rich and electron-deficient heteroarenes with the aid of heteroatom-directing C-H bond activation. The regioselectivity of the second borylation was controlled by both steric factors and the electronic effect of the silyl group installed in the first step. In combination with the classic cross-coupling reaction, this method provides rapid access to multisubstituted heteroarenes.
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Iridium-Catalyzed Sequential Silylation and Borylation of Heteroarenes Based on Regioselective C−H Bond Activation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201801229] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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37
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Abstract P2-01-08: Enumeration of heterogeneous circulating tumor cells (CTCs) using size-based method in early, and metastatic, breast cancer patients. Cancer Res 2018. [DOI: 10.1158/1538-7445.sabcs17-p2-01-08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background
The detection of circulating tumor cells (CTCs) in peripheral blood is an independent predictor of the efficacy of systemic therapy, and also a prognostic marker for patients with metastatic breast cancer. One of the main methods to detect CTCs is CellSearch system, which uses immune-magnetic separation followed by immunocytochemistry. A microdevice (CTChip from ClearCell system) can capture and enumerate CTCs based on distinctive physiological differences (size and deformability) between cancer cells and blood cells. CTChip thus obtains a larger CTC yield than affinity-based separation, which enriches a particular subgroup of cells expressing EpCAM. In this study, we enumerate CTCs in peripheral blood from early and metastatic breast cancer patients using a size-based method.
Patients and methods
We examined blood samples from a total of 18 early and metastatic breast cancer patients, after obtaining written informed consent. Blood samples were taken in sodium EDTA tubes after discarding the first 1ml of blood from the syringe. Two ml blood samples were applied to CTChip (ClearCell system), and CTCs were eventually trapped in the microwells of the CTChip. Trapped cells were analyzed by immunocytochemistry with monoclonal antibodies specific for leukocytes (CD45) and epithelial cells (CK8/18), along with 4',6-diamidino-2-phenylindole (DAPI) for nuclei: CK8/18-positive, DAPI-positive and CD45-negative cells more than 10 μm in diameter were defined as CTCs. Eight patients were examined using both the CTChip and CellSearch system to compare the yield of CTCs.
Results
Of 18 patients, 6 were de novo stage IV, 6 were recurrent and 6 were early stage breast cancer patients. Of primary tumors, 8 were HER2- and ER and/or PR +, 6 were HER2-and ER- and PR-, 3 were HER2+ and ER and/or PR +, and one was HER2+ and ER- and PR-. Using CTChip, detected CTCs ranged from 3 - 107 cells/2 ml in all cases: 3 - 83 for early stage, 19 - 156 for stage IV and 21 - 146 for recurrent. The number of CTCs found in recurrent patients tended to be higher than in early stage patients. Size-based method using CTChip clearly showed high sensitivity compared with the CellSearch system, which detected CTCs in only 2 cases out of 8. In analysis by immunochemistry, we found CK-negative, CD45-negative and DAPI positive cells with larger diameter (>16 μm) than CK-positive CTCs in most patients, and the numbers were higher in stage IV (8.5 cells of median value) and recurrent (13 cells) patients than in early stage patients (1.5 cells). Our study suggested that CK-negative large cells might be CTCs with epithelial–mesenchymal transition (EMT).
Conclusion
This size-based technology enables us to capture CTCs regardless of EpCAM expression. Enumerated CTCs varied in size and positivity of CK8/18, suggesting the heterogeneity of CTCs. Further research, especially focusing on EMT will be crucial to understand the key mechanism of metastasis and drug resistance.
Citation Format: Tozuka K, Nagai SE, Kubo K, Komatsu K, Takai K, Inoue K, Matsumoto H, Hayashi Y, Tsuboi M, Yamada Y, Wang X, Suganuma M. Enumeration of heterogeneous circulating tumor cells (CTCs) using size-based method in early, and metastatic, breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-01-08.
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Abstract P4-13-11: A complication analysis between complete and partial tissue expander coverage using autologous flaps in cases of immediate breast reconstruction. Cancer Res 2018. [DOI: 10.1158/1538-7445.sabcs17-p4-13-11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background:
To avoid tissue expander exposure following mastectomy flap necrosis, several methods for covering expander by autologous flap in cases of immediate breast reconstruction have been reported. These methods are classified into two groups, complete or partial expander coverage. Two methods have potential risks of postoperative complications following: insufficient lower pole expansion and cranial migration in complete coverage methods, and lateral migration in partial coverage methods. However, the comparisons of complication rates between these two methods have not been reported. This study aims to compare the incidence of expander exposure following mastectomy flap necrosis and expander migration between two methods.
Methods:
A retrospective review of 93 patients (99 breasts) who underwent immediate expander-based breast reconstruction was performed. Patients were divided into two groups, complete or partial expander coverage by autologous flaps. In both groups, expanders were placed into subpectral position. In partial coverage group, the lateral borders of pectralis major muscles were sutured to the mastectomy skin flaps. If the skin flap was too thin to be sutured, the serratus anterior muscro-fascial flap was dissected and sutured to the lateral border of pectralis major muscle to cover the expander completely. Allograft products were not used in both groups. Demographics, intraoperative findings, and postoperative complications were compared between two groups.
Results:
Of the 99 breasts, 56 underwent complete expander coverage and 43 underwent partial coverage. Mastectomy flap necrosis rate was higher in the complete coverage group (Complete 14.3% versus Partial 0%; p=0.0091), however, there was no incidence of expander exposure in both groups. Lateral migration rate was higher in the partial coverage group (Complete 0% versus Partial 9.3%; p=0.033). There was no difference in cranial migration rate between two groups (Complete 12.5% versus Partial 2.3%; p=0.133).
Conclusions:
The thinness of the mastectomy flaps was considered to provide the higher incidence of mastectomy flap necrosis in the complete coverage group. The complete expander coverage reduced lateral migration rate and prevented expander exposure in cases of mastectomy flap necrosis.
Citation Format: Kubo K, Hamahata A, Tozuka K, Tsuboi M, Hayashi Y, Takai K, Saito T, Sakurai H, Matsumoto H. A complication analysis between complete and partial tissue expander coverage using autologous flaps in cases of immediate breast reconstruction [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-13-11.
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Synthesis of Borylcyclopropanes by Chromium-Promoted Cyclopropanation of Unactivated Alkenes. Org Lett 2017; 19:6104-6107. [PMID: 29083928 DOI: 10.1021/acs.orglett.7b02956] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The combination of diiodomethylboronate ester, CrCl2 with TMEDA promoted borylcyclopropanation of unactivated alkenes under mild conditions. Compared with the typical Simmons-Smith cyclopropanation, the current protocol offers the following advantages: (1) the reaction proceeds stereoselectively with disubstituted alkenes even without hydroxy or alkoxy groups; (2) both electron-rich and electron-deficient alkenes can be applicable; and (3) the reaction does not require potentially flammable alkylzinc. These unique reactivity features result from the steric and electronic nature of the gem-dichromiomethane intermediates.
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Azulene-Fused Linear Polycyclic Aromatic Hydrocarbons with Small Bandgap, High Stability, and Reversible Stimuli Responsiveness. Org Lett 2017; 19:5585-5588. [PMID: 28980817 DOI: 10.1021/acs.orglett.7b02729] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Azulene-fused polycyclic aromatic hydrocarbons (PAHs) were synthesized from commercially available azulene in four steps. The resulting azulene conjugates exhibited significantly narrow HOMO-LUMO bandgaps with high air stability, confirmed by photophysical study. Introduction of azulene also enabled the unique reversible stimuli-responsiveness even with the weak acid and base, which can potentially control the degree of conjugation and optoelectronic properties by simple acid-base and redox processes.
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CT findings in 11 patients with TAFRO syndrome: a variant of multicentric Castleman's disease. Clin Radiol 2017. [DOI: 10.1016/j.crad.2017.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Structural Characterization and Unique Catalytic Performance of Silyl-Group-Substituted Geminal Dichromiomethane Complexes Stabilized with a Diamine Ligand. J Am Chem Soc 2017; 139:13184-13192. [PMID: 28814078 DOI: 10.1021/jacs.7b07487] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Stabilization by a silyl group on the methylene carbon and a diamine ligand led to the isolation of gem-dichromiomethane species. X-ray crystallography confirmed the identity of the structure of this rare example of reactive gem-dimetalloalkane species. The isolated gem-dichromiomethane complex acted as a storable silylmethylidene carbene equivalent, with reactivity that could be changed dramatically upon addition of a Lewis acid (ZnCl2) and a base (TMEDA) to promote both silylalkylidenation of polar aldehydes and silylcyclopropanation of nonpolar alkenes. Identification of a key reactive species also identified the catalytic version of these transformations and provided insights into the reaction mechanism. In contrast to Simmons-Smith cyclopropanation, the real reactive species for the current cyclopropanation was a chromiocarbene species, not a chromium carbenoid species.
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Characterization of patients with systemic lupus erythematosus who meet the diagnostic criteria for TAFRO syndrome. Lupus 2017; 27:417-427. [DOI: 10.1177/0961203317725589] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Purpose TAFRO syndrome is a novel disorder manifesting as fever, anasarca, thrombocytopenia, renal insufficiency and organomegaly, and its etiology has not been clarified. The aim of this study was to elucidate similarities and differences between systemic lupus erythematosus (SLE) and TAFRO syndrome. Methods We examined 46 consecutive patients diagnosed with SLE and determined whether they meet the proposed diagnostic criteria for TAFRO syndrome (2015 version). Results Of the 46 patients with SLE, four (8.7%) also met the TAFRO syndrome criteria (TAFRO-like group). All patients in the TAFRO-like group were males, and their mean age was significantly higher than that of the non-TAFRO group (67.5 ± 8.7 vs. 39.3 ± 18.1 years, p = 0.004). C-reactive protein and γ-glutamyl transpeptidase levels were significantly higher, and frequencies of anti-dsDNA and anti-Sm antibodies were significantly lower in the TAFRO-like than non-TAFRO group. Elder cases (onset age ≥ 50 years) met significantly more categories of the diagnostic criteria for TAFRO syndrome than did those with younger cases. Conclusions Several patients with SLE, especially elder cases, showed features similar to those of TAFRO syndrome. Although exclusion of SLE is needed in the diagnostic criteria for TAFRO syndrome, TAFRO syndrome-like SLE should be considered.
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Iridium-catalysed hydrosilylation of cyclopropanes via regioselective carbon-carbon bond cleavage. Chem Commun (Camb) 2017; 53:9281-9284. [PMID: 28771260 DOI: 10.1039/c7cc04296e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
While cyclopropanes have been explored as synthetically valuable building blocks, their transformation without conjugated substituents or directly substituted heteroatoms remains challenging. The current study describes the iridium-catalysed ring-opening hydrosilylation of cyclopropanes. A nitrogen-based directing group was found to control the reactivity of iridium active species as well as the regiochemistry of carbon-carbon bond cleavage and hydrosilylation.
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Rhodium-Catalyzed Silylative and Germylative Cyclization with Dehydrogenation Leading to 9-Sila- and 9-Germafluorenes: A Combined Experimental and Computational Mechanistic Study. Chemistry 2017; 23:10861-10870. [DOI: 10.1002/chem.201701579] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Indexed: 11/09/2022]
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Iridium-catalyzed Dehydrogenative Dimerization of Benzylmethylsilanes via Silylation of C(sp3)–H Bonds Adjacent to a Silicon Atom. CHEM LETT 2017. [DOI: 10.1246/cl.170369] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Rhenium-Catalyzed Construction of Polycyclic Hydrocarbon Frameworks by a Unique Cyclization of 1,n
-Diynes Initiated by 1,1-Difunctionalization with Carbon Nucleophiles. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201701159] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Rhenium-Catalyzed Construction of Polycyclic Hydrocarbon Frameworks by a Unique Cyclization of 1,n
-Diynes Initiated by 1,1-Difunctionalization with Carbon Nucleophiles. Angew Chem Int Ed Engl 2017; 56:5862-5866. [DOI: 10.1002/anie.201701159] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Indexed: 11/08/2022]
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Synthesis and Properties of Sila[n]helicenes via Dehydrogenative Silylation of C-H Bonds under Rhodium Catalysis. Org Lett 2016; 18:4380-3. [PMID: 27513028 DOI: 10.1021/acs.orglett.6b02134] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Use of a rhodium catalyst with (R)-(S)-BPPFA ligand allows efficient synthesis of sila[n]helicenes via dehydrogenative silylation of C-H bonds. By selecting the proper ligands, the current method provides the ability to prepare unsymmetrical sila[n]helicene derivatives without any oxidants. The resulting sila[6]helicene is a rare example of a five-membered ring-fused [6]helicene, which was isolated as a single pure enantiomer without substituents on the terminal benzene rings.
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