Use of Base Control To Provide High Selectivity between Diaryl Thioether and Diaryl Disulfide for C–S Coupling Reactions of Aryl Halides and Sulfur and a Mechanistic Study
Previous studies have reported that S-arylation produces diaryldisulfide when the precursors include sulfur powder and aryl halide using CuI as the catalyst. However, our research has revealed that the use of different bases in the above S-arylation process results in the coproduction of diarylsulfane and diaryldisulfane. In addition, we have demonstrated that the ratio of the two products can be
先前的研究报道,当前体包括硫粉和使用CuI作为催化剂的芳基卤化物时,S-芳基化反应将生成二芳基二硫化物。但是,我们的研究表明,在上述S-芳基化过程中使用不同的碱会导致联产二芳基硫烷和二芳基二硫烷。另外,我们证明了可以通过选择碱的碱度来控制两种产物的比例。1个1 H NMR谱表明,二芳基二硫醚是第一产物,通过CuI催化与芳基卤化物反应生成二芳基硫烷成为试剂。使用各种不同的碱,对各种芳基卤化物进行了测试,以提高二芳基硫烷和二芳基二硫烷之间的选择性,从而得出以下原理。弱碱,例如金属碳酸盐或乙酸盐,只会产生二芳基二硫醚;强碱(例如金属氢氧化物)会同时生成二芳基二硫烷和二芳基硫烷。根据DFT计算,氢氧根离子被碘离子交换并与铜键合,从而更强烈地影响铜电子以还原二芳基二硫化物。
Benzo-fused thromboxane synthetase inhibitors
申请人:Pfizer Inc.
公开号:US04496572A1
公开(公告)日:1985-01-29
A novel series of carboxy-substituted naphthalenes and carboxy-substituted benzo-fused heterocycles, such as carboxy-substituted derivatives of indole, benzofuran and benzothiophene, has been prepared, including their pharmaceutically acceptable salts. These particular compounds are useful in therapy for the treatment of thrombosis, ischaemic heart disease, stroke, transient ischaemic attack, migraine, peripheral vascular disease, the vascular complications of diabetes and endotoxic shock. Preferred member compounds include 2-(1-imidazolylmethyl)-3-methylbenzo[b]thiophene-5-carboxylic acid and 3-methyl-2-(3-pyridylmethyl)benzo[b]thiophene-5-carboxylic acid, respectively. Methods for preparing these compounds from known starting materials are provided.
A simple and efficient protocol for copper-catalyzed coupling reactions between aryl halides and elemental sulfur or selenium has been developed. A variety of disulfides and diselenides can be obtained in moderate to excellent yields up to 96%.
[EN] CARBACEPHEM ß-LACTAM ANTIBIOTICS<br/>[FR] ANTIBIOTIQUES BÊTA-LACTAMES À CARBACÉPHÈME
申请人:ACHAOGEN INC
公开号:WO2009055696A1
公开(公告)日:2009-04-30
Carbacephem β-lactam antibiotics having the following chemical structures (I) and (II) are disclosed, including stereoisomers, pharmaceutically acceptable salts, esters and prodrugs thereof, wherein Ar2, R1, R2 and R3 are as defined herein. The compounds are useful for the treatment of bacterial infections, in particular those caused by methicillin-resistant Staphylococcus spp.
Arylsulfides (and diaryldisulfides obtained spontaneously by oxidation of the arylsulfides during the work-up) and diarylsulfides can be obtained by substituting aryl radicals by the thiourea anion in liquidammonia under an electrochemical inducement.