Group 13 sulfides hydrogen peroxide

A heterocyclic ring may be used in place of one of the benzene rings without loss of biologic activity. The first step in the synthesis of such an agent starts by Friedel-Crafts-like acylation rather than displacement. Thus, reaction of sulfenyl chloride, 222, with 2-aminothiazole (223) in the presence of acetic anhydride affords the sulfide, 224. The amine is then protected as the amide (225). Oxidation with hydrogen peroxide leads to the corresponding sulfone (226) hydrolysis followed by reduction of the nitro group then affords thiazosulfone (227). ... 

Bordwell and Boutan (BB)81 carried out extensive work on the methylsulfmyl group in 1957. It must be emphasized that they found that the preparation of pure arylmethyl sulfoxides from arylmethyl sulfides by oxidation was not a trivial matter. The frequently recommended reagent, hydrogen peroxide in acetic acid, tended to give sulfoxides contaminated with appreciable quantities of sulfones, which could not be removed by fractional crystallization. Oxidation by nitric acid was found to be more satisfactory. 

In addition to the enantioselective preparation of 1,3-dithiane 1 -oxides, our group has been concerned with the development of novel methods for the catalytic asymmetric oxidation of other prochiral sulfides our currently preferred system employs an enantiomerically pure sulfonylimine and commercially available hydrogen peroxide.70... 

The penicillin-G-potassium salt has been oxidized using supported polyoxo-metallates.62 Specifically, the oxidation of the sulfide group to give the sulfoxide was achieved, the product being an intermediate in the production of Cephalosporin antibiotics.63 The selective oxidation of benzenethiol to benzenesulfonic acid with hydrogen peroxide was effectively catalysed by phosphotungstic acid on y-alumina.62 This was in contrast to the homogeneous oxidation where the disulfide was produced in substantial yields. 

Several medio are available for the intnxluction of sulfenyl groups a to carbonyl derivatives and these have been reviewed. - The most versatile procedure involves reaction of the enolate with an appropriate thiol derivative, but the preferred m od is largely dependent on the nature of the substrate employed (see below). In most instances, sulfur has been introduced in the divalent state and subsequently oxidized, although the oxidative step has been avoided by the direct introduction of sulfur at the S oxidation level. The oxidation of sulfides to sulfoxides is a trivial procedure that can be effected by a variety of reagents. Sodium metaperiodate, m-chloroperbenzoic acid and hydrogen peroxide are the most common oxidants, but r-butyl hydroperoxide, r-butyl hypochlorite, N-chlorobenzotriazole,... 

The oxidation tolerates many functional groups, including alkyl sulfide, and has been used for the oxidation of cyclopropylboranes (see references 19 and 54) however, it has also been used to produce acylsilanes (equation 25) which are particularly sensitive to alkaline hydrogen peroxide. 

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