Convenient Synthesis of 5-Trifluoroacetylated Imidazoles by Ring Transformation of Mesoionic 1,3-Oxazolium-5-olates.
作者:Masami KAWASE、Setsuo SAITO
DOI:10.1248/cpb.48.410
日期:——
Mesoionic 4-trifluoroacetyl-1, 3-oxazolium-5-olates (1), obtained from the reaction of N-acyl-N-alkylglycines (2) with trifluoroacetic anhydride, react with amidines to give 5-trifluoroacetylimidazoles (3) in moderate yield. The novel ring trandformations of 1 into 3 occur via an initial attack of amidines on the C-2 position of the ring.
中性离子型 4-三氟乙酰基-1, 3-噁唑鎓盐-5-醇盐(1),是通过N-氨酰-N-烷基甘氨酸(2)与三氟乙酸酐反应得到的,能够与胍类化合物反应,生成5-三氟乙酰基咪唑(3),产率适中。这一新颖的环转化反应是通过胍类对环的C-2位的初步攻击实现的。