Ring Transformations via Bridged 1,3-Dicarbonyl Heteroanalogs; Part II.<sup>1</sup>. Synthesis of 4-(ω-Aminoalkyl)-thiazoles by a Novel Ring Transformation Reaction of Semicyclic Thioacylamidines with Acidic Methyl Halides
作者:Jürgen Liebscher、Michael Pätzel、Ute Bechstein
DOI:10.1055/s-1989-27452
日期:——
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。