Semicyclic N′-(thioacyl)amidines 1 react with acidic methyl halides 2 as C-synthons via S-alkylation and cyclization to give 4-(Ï-aminoalkyl)-thiazole hydrohalides 5. In this transformation, the thiazole ring is formed while the initial lactam ring is opened. In contrast, semicyclic N-(thioacyl)amidines 1 react with α-haloketones as C-C building blocks in a Hantzsch-type thiazole synthesis affording semicyclic 2-amidinothiazoles 6 or thiazolium salt 7 while the starting lactamimine ring is retained.
半环化N'-(
硫代酰基)脒1在S-烷基化和环化过程中,与酸性甲基卤化物2作为C-合成子反应,生成4-(γ-
氨基烷基)
噻唑氢卤酸盐5。在这一转化过程中,形成了
噻唑环,同时初始的乳酰胺环被打开。相比之下,半环化N-(
硫代酰基)脒1与α-卤代酮作为C-C构建块在Hantzsch型
噻唑合成中反应,生成半环化2-脒基
噻唑6或
噻唑盐7,同时保留了起始的乳
酰亚胺环。