Natarajan Amarnath, Guo Yuhong, Arthanari Haribabu, Wagner Gerhard, Halperin Jose A, Chorev Michael
Laboratory for Translational Research, 1 Kendall Square, Building 600 3rd Floor, Harvard Medical School, Cambridge, Massachusetts 02139, USA.
J Org Chem. 2005 Aug 5;70(16):6362-8. doi: 10.1021/jo0508189.
A thiophile-promoted synthesis of disubstituted 4H-[1,2,4]triazole-3-yl-amines as urea mimetics from the corresponding 1,3-disubstituted thioureas has been studied, and the scope and limitations of this reaction are presented. The reaction proceeds through the formation of a carbodiimide, followed by a sequential addition--dehydration with acyl hydrazides. 1,3-Branched dialkylthioureas result in the formation of the corresponding ureas. The electronic and steric effects of the substitution on the phenyl rings of the 1,3-diarylthioureas play an important role in the formation of the intermediary carbodiimde and the direction of the subsequent ring closure of the N-acyl hydrazide adduct.
研究了一种由亲硫试剂促进的、从相应的1,3-二取代硫脲合成作为尿素模拟物的二取代4H-[1,2,4]三唑-3-基胺的方法,并阐述了该反应的适用范围和局限性。该反应通过形成碳二亚胺进行,随后与酰肼依次进行加成-脱水反应。1,3-支链二烷基硫脲会生成相应的脲。1,3-二芳基硫脲苯环上取代基的电子效应和空间效应在中间体碳二亚胺的形成以及随后N-酰肼加合物的闭环方向中起着重要作用。