- NaClO2-mediated preparation of pyridine-2-sulfonyl chlorides and synthesis of chiral sulfonamides
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A simple method to prepare azaarenesulfonyl chlorides by NaClO2-mediated oxidative chlorination of azaarenethiols have been developed, with water as the solvent. Easy purification by simple extraction and concentration gives the products in good yields. The azaarenesulfonyl chlorides readily undergo condensation with chiral amines to afford chiral sulfonamides.
- Xu, Dong,Yang, Shiyi,Gao, Aijun,Yang, Zhanhui
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p. 463 - 473
(2020/07/03)
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- Grignard-Reagent-Promoted Desulfonylation/Intramolecular Coupling for the Synthesis of 2-(1-Fluorovinyl)pyridines
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A novel process involving Grignard-reagent-promoted desulfonylation/intramolecular coupling of readily available α-fluoro-α,β-unsaturated-(2-pyridyl)sulfones was realized that provided a series of polysubstituted 2-(1-fluorovinyl)pyridines in good yields. The intrinsic coordination between pyridine and Mg(II) along with the "negative fluorine effect"of the substrates should play the key role for the smooth transformation in the absence of transition-metal catalysts.
- Jiang, Gaoxi,Kang, Lei,Qian, Jinlong,Yang, Huameng,Zhang, Jinlong
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supporting information
p. 9118 - 9122
(2020/12/02)
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- Synthesis and characterization of 2-pyridylsulfur pentafluorides
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Current approaches to prepare SF5-substituted heterocycles during the synthesis of targeted heterocyclic compounds require the use of SF5-functionalized aryl or alkyne reagents or SF5Cl as a source of the SF5 functional group. Herein we report that excess oxidative fluorination of 2,2' -dipyridyl disulfide with a KF/Cl2 /MeCN system leads to the formation of thirteen new 2-pyridylsulfur chlorotetrafluorides (2-SF4Cl-pyridines). These molecules are found to undergo further chlorine-fluorine exchange reactions by treatment with silver(I) fluoride enabling ready access to a series of ten new substituted 2-pyridylsulfur pentafluorides (2-SF5-pyridines). This is the first preparatively simple and readily scalable example of the transformation of an existing heterocyclic sulfur functionality to prepare SF5-substituted heterocycles.
- Kanishchev, Oleksandr S.,Dolbier, William R.
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supporting information
p. 280 - 284
(2015/04/21)
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- Exploring the influence of the protein environment on metal-binding pharmacophores
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The binding of a series of metal-binding pharmacophores (MBPs) related to the ligand 1-hydroxypyridine-2-(1H)-thione (1,2-HOPTO) in the active site of human carbonic anhydrase II (hCAII) has been investigated. The presence and/or position of a single methyl substituent drastically alters inhibitor potency and can result in coordination modes not observed in small-molecule model complexes. It is shown that this unexpected binding mode is the result of a steric clash between the methyl group and a highly ordered water network in the active site that is further stabilized by the formation of a hydrogen bond and favorable hydrophobic contacts. The affinity of MBPs is dependent on a large number of factors including donor atom identity, orientation, electrostatics, and van der Waals interactions. These results suggest that metal coordination by metalloenzyme inhibitors is a malleable interaction and that it is thus more appropriate to consider the metal-binding motif of these inhibitors as a pharmacophore rather than a "chelator". The rational design of inhibitors targeting metalloenzymes will benefit greatly from a deeper understanding of the interplay between the variety of forces governing the binding of MBPs to active site metal ions.
- Martin, David P.,Blachly, Patrick G.,McCammon, J. Andrew,Cohen, Seth M.
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supporting information
p. 7126 - 7135
(2014/11/07)
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- Modelling nucleophilic substitution at silicon in solution using hypervalent silicon compounds based on 2-thiopyridones
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Halodimethylsilylmethyl derivatives of 2-thiopyridones have been prepared. The N-CH2 isomer is favoured with the 6-methylthiopyridone. 13C and 29Si chemical shifts have been used to calculate the extent of sulfur-silicon bond formation and the extent of pentacoordination. The results are consistent with the oxygen analogues and reveal that as expected sulfur is a poorer nucleophile than oxygen. The unsubstituted thiopyridone and the 5-trifluoromethyl derivative favour the S-CH2 isomer. Again the mapping of nucleophilic substitution by nitrogen is in line with sulfur and oxygen nucleophiles, but in this series nitrogen is a poorer nucleophile than expected. The results are discussed in terms of steric strain, the preferences for alkylation of the pyridones and the bond strength of coordination to silicon.
- Bassindale, Alan R.,Parker, David J.,Taylor, Peter G.
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p. 1059 - 1066
(2007/10/03)
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- Azetidinone compounds useful in the preparation of carbapenem antibiotics and process for preparing carbapenem and penem compounds
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Compounds of formula (I): STR1 wherein: R1 is hydrogen or a hydroxy-protecting group; R2 is alkyl, alkoxy, halogen, optionally substituted phenyl or optionally substituted phenoxy; R3 is optionally substituted pyridyl, optionally substituted quinolyl or phenyl group which has a substituent of formula --CYNR5 R6, where Y is oxygen or sulfur, and R5 and R6 are each alkyl, aryl or aralkyl, or R5 and R6 and the nitrogen to which they are attached together form a heterocyclic group; is R4 hydrogen or an amino-protecting group; and Z is sulfur or oxygen; are valuable intermediates in the preparation of carbapenem compounds and retain a desirable configuration during conversion to such carbapenem compounds. Penem and carbapenem compounds having a group of formula --SA' are prepared from a corresponding compound having a substituted thio, sulfinyl or sulfonyl group at this position by reaction with a compound A'SH (where A' is an organic group) in the presence of a salt of a metal of Group II or III of the Periodic Table.
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- The Synthesis and Some Reactions of Novel Pyridine-2(1H)-thiones
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The use of methyl 3-mercaptopropionate for the conversion of halogenated pyridins to pyridine thiones and thiols is described, and limitations of the reaction discussed.S-Alkylation and oxidation reactions of the products from these reactions are reported.
- Dunn, A. D.,Norrie, R.,L'Hostis, J.,Marjot, S.
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p. 119 - 125
(2007/10/02)
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