A Useful and Environmentally Benign Synthetic Protocol for Dethiolization by Employing Vanadium Pentoxide Catalyzed Oxidation of Ammonium Bromide by Hydrogen Peroxide
作者:Ejabul Mondal、Gopal Bose、Priti Rani Sahu、Abu T. Khan
DOI:10.1246/cl.2001.1158
日期:2001.11
presence of olefin and aromatic ring as well as other protecting groups to carbonyl compounds by employing V2O5 catalyzedoxidation of ammonium bromide by H2O2 in CH2Cl2–H2O solvent system; mild conditions, high selectivity, good yield, and no side products such as bromination or oxidation are some of the major advantages.
diethylmercaptal, benzophenone diethylmercaptole, ethyl orthotrithioformate and benzyl methylsulfide, react with copper(II) salts of 1,3-dicarbonyl compounds, active methylene compounds or anisole, in the presence of cupric chloride, to give condensation or substitution products in good yields accompanied with carbon-sulfur bond cleavage. On the other hand, in the absence of cupric chloride, the bivalent
发现二价硫化合物如苯甲醛二乙基硫醇、二苯甲酮二乙基硫醇、原三硫代甲酸乙酯和苄基甲硫醚在氯化铜存在下与1,3-二羰基化合物、活性亚甲基化合物或苯甲醚的铜(II)盐反应,以良好的收率得到缩合或取代产物,并伴有碳硫键断裂。另一方面,在不存在氯化铜的情况下,二价硫化合物不发生反应,原料被回收。这些结果可以通过假设从二价硫化合物和铜 (II) 初始形成活性络合物来解释。
Partial Reduction of Dithioacetals with Phosphorus Reagents
dithioacetals 1 derived from di- and monoaryl ketones were monodesulfurized with diphosphorus tetraiodide or dimethyl phosphonate. A side product 5 from the reaction of 9,9-bis(ethylthio)-9H-fluorene with phosphorus triiodide suggested the intermediacy of an anionic species.
Preferential hydrolysis of benzylic/allylic dithianes and dithiolanes using o-iodoxybenzoic acid (IBX) in DMSO containing traces of water
作者:Yikang Wu、Xin Shen、Jia-Hui Huang、Chao-Jun Tang、He-Hua Liu、Qi Hu
DOI:10.1016/s0040-4039(02)01346-1
日期:2002.9
Dithianes and dithiolanes at benzylic or allylic carbons can easily be hydrolyzed by IBX in DMSO, whereas non-activated dithianes/dithiolanes are much more stable under these conditions. (C) 2002 Elsevier Science Ltd. All rights reserved.