Enzymatic Synthesis of Optically Active a-Hydroxybenzylpyridines
摘要:
Synthesis of optically active alpha-hydroxybenzylpyridines by asymmetric reduction of benzoylpyridines and benzoylpyridine N-oxides with baker's yeast, and enantioselective esterification of racemic alpha-hydroxybenzylpyridines by use of lipase PS have been described.
Pyrazolo[3,4-<i>b</i>]pyridines: Syntheses, reactions, and nuclear magnetic resonance spectra
作者:Brian Maurice Lynch、Misbahul Ain Khan、Huk Chia Teo、Francisco Pedrotti
DOI:10.1139/v88-074
日期:1988.3.1
2-Chloro-3-formylpyridine (2-chloronicotinaldehyde) was obtained by reduction of 2-chloro-3-cyanopyridine by Raney nickel and formic acid (3 1); this intermediate is inaccessible by the above N-oxidation route (peroxyacid oxidation of 3-formylpyridine yields pyridine-N-oxide 3-carboxylic acid). In the synthesis of the parent 1 from 2-chloro-3-formylpyridine, the yield was prejudiced by the formation
A practical, efficient, and rapid method for the oxidation of electron deficient pyridines using trifluoroacetic anhydride and hydrogen peroxide–urea complex
作者:Stéphane Caron、Nga M Do、Janice E Sieser
DOI:10.1016/s0040-4039(00)00165-9
日期:2000.4
A general method for the oxidation of electron-poor pyridines to their N-oxides using UHP and TFAA in either CH2Cl2 or CH3CN was developed. The methodology proved to tolerate a number of functional groups and substitution patterns and proceeded on notoriously difficult to oxidize substrates.
3- and 4-(α-diazobenzyl)pyridine-N-oxides as photoresponsive magnetic couplers for 2p–4f heterospin systems: formation of carbene–Tb<sup>III</sup> and carbene–Dy<sup>III</sup> single-molecule magnets
作者:Kensuke Murashima、Satoru Karasawa、Kenji Yoza、Yuji Inagaki、Noboru Koga
DOI:10.1039/c6dt00420b
日期:——
3- and 4-(α-diazophenyl)pyridine-N-oxides, 3- and 4-D1pyO, were prepared as new photoresponsive magnetic couplers in heterospin systems. Lanthanide dinuclear complexes, [LnIII(tta)3(4-D1pyO)]2; LnIII = Gd (1d), Tb (2d), and Dy (3d) and tta = 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate, bridged with 4-D1pyO in μ2 coordination mode were obtained. The obtained 1d, 2d, and 3d were isostructures. The
C–H dithiocarbonation of quinoline N-oxides with various potassium O-alkyl xanthates. The reaction performed well under transition-metal-free, base-free, and room-temperature conditions with wide substrate tolerance. Employing potassium O-tert-butyl xanthate (tBuOCS2K) as a nucleophile, some valuable quinoline-2-thiones were unexpectedly obtained in a one-pot reaction without any additional base.
通过 Ts 2 O 促进的喹啉 N-氧化物与各种 O-烷基黄原酸钾的脱氧 C-H 二硫代碳酸化反应,开发了一种简单、有效且实用的合成 S-喹啉黄原酸的方法。该反应在无过渡金属、无碱和室温条件下表现良好,具有广泛的底物耐受性。使用O-叔丁基黄原酸钾( t BuOCS 2 K)作为亲核试剂,在没有任何额外碱的情况下,在一锅反应中意外地获得了一些有价值的喹啉-2-硫酮。
Simple method for the introduction of tetrafluoroethyl substituents into nitrogen heterocycles
作者:Rafał Loska、Mieczysław Mąkosza
DOI:10.1070/mc2006v016n03abeh002335
日期:2006.1
A mild and convenient method for the preparation of 1,2,2,2-tetrafluoroethyl-substituted nitrogen heterocycles via a reaction of hexafluoropropene with azine and azole N-oxides is reported.