Ketene S,S-acetals 2 react with 2-amino-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-unsaturated acids to give thiazolo[3,2-a] pyrid-5-one derivatives 4, 6, and 7 through an electrophilic addition and cyclocondensation sequences.
烯酮 S,S-
乙醛 2 与 2-
氨基-1-
乙硫醇反应,生成取代的 2-亚甲基
噻唑烷 3。光谱数据证实了这些产物的结构为烯酮 N,S-
乙醛。化合物 3a-f 与 δ,δ-不饱和酸的酯反应,通过亲电加成和环缩合顺序,得到
噻唑并[3,2-a]
吡啶-5-酮衍
生物 4、6 和 7。