Studies on Acetylenic Compounds. XXII. Ring Closure. (4). New Synthesis of Thiazoles and Imidazole.
作者:Yasuo Yura
DOI:10.1248/cpb.10.376
日期:——
It was found that the compounds having the general formula RCH(X)-C≡C-R'gave thiazole derivatives by reaction with thiourea. The relationship between the structure of thiazoles and substituent groups was clarified as follows : (1) When R=R'=Ph, 2-amino-4-benzyl-5-phenylthiazole (IId) is obtained, (2) When R=alkyl, R'=H, two kinds of thiazoles are obtained ; and (3) when R=R'=alkyl, thiazole derivative is not obtained. Similarly, propargyl bromide and phenylpropargyl bromide, when reacted with ammonium dithiocarbamate, afforded 2-mercapto-4-methylthiazole (XX) and 2-mercapto-4-benzylthiazole (XXIII), respectively. Further, 2-amino-4-methylimidazole (XXV) was obtained from guanidine and propargyl bromide.
研究发现,具有通式RCH(X)-C≡C-R'的化合物在反应中与硫脲作用生成噻唑衍生物。噻唑结构和取代基之间的关系阐明如下:(1) 当R=R'=Ph时,获得2-氨基-4-苄基-5-苯基噻唑(IId);(2) 当R=烷基,R'=H时,获得两种噻唑;(3) 当R=R'=烷基时,不生成噻唑衍生物。同样地,炔丙基溴和苯基炔丙基溴与氨荒酸盐反应,分别得到2-巯基-4-甲基噻唑(XX)和2-巯基-4-苄基噻唑(XXIII)。进一步地,从胍和炔丙基溴获得2-氨基-4-甲基咪唑(XXV)。