Synthesis of Heterocyclic Ketene N,S-Acetals and Their Reactions with Esters of α,β-Unsaturated Acids

TLDR: In this article, the structure of these products as ketene N,S-acetals is confirmed by spectroscopic data, and they are shown to react with esters of α,β-yunsaturated acids to give thiazolo[3,2-a]pyrid-5-one derivatives.

Abstract: Ketene S,S-acetals 2 react with 2-almino-1-ethanethiol to afford the substituted 2-methylenethiazolidines 3. The structure of these products as ketene N,S-acetals is confirmed by spectroscopic data. Compounds 3a-f react with esters of α,β-yunsaturated acids to give thiazolo[3,2-a]pyrid-5-one derivatives 4, 6, and 7 through an electrophilic addition and cyclocondensation sequences