Synthesis and Reactions of Thiaminedisulfide Sulfur Derivatives

概要

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Methylsulfinylethylthiamine (MSIT) (I) was found to be converted readily into a mixture of disulfides in aqueous solution at pH 7-8. Disulfides II and III were isolated and their structures were confirmed to be MSIT-disulfide and MTETDS (methylthioethyl-thiaminedisulfide), respectively. Disulfide IV could not be isolated in a pure state, but rapid disproportionation into a mixture of II and III suggested that IV is a mixed disulfide of MSIT and MTET. In buffer solution at pH 8,the disappearance of MSIT followed first-order kinetics with 2.53×10^<-3> sec^<-1> at 60°, and the activation energy was found to be 23.8 kcal/mol. Clearly, the sulfoxide group in MSIT plays an important role in this transformation reaction. In the proposed reaction route, MSIT reacts with two mol of alkali to produce ring opened thiol and intramolecular thiol-sulfoxide interaction occurs to form an unstable thiol-sulfoxide adduct that is rapidly destroyed by reaction with another molecule of thiol to give an unsymmetrical disulfide (IV). Disproportionation of IV follows to afford a mixture of symmetrical disulfides II and III. Independent synthesis of II and III was also achieved via halogeno-SB_1. Compounds II and III show high anticoccidial activities against avian coccidiosis.
公益社団法人日本薬学会の論文
1978-12-25