Convenient Synthesis of 4-Trifluoromethyl-Substituted Imidazole Derivatives.
作者:Masami KAWASE、Setsuo SAITO、Teruo KURIHARA
DOI:10.1248/cpb.49.461
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 ammonia to give 4-trifluoromethyl-3, 4-dihydroimidazoles (3) in high yields. Dehydration of 3 gives 4-trifluoromethylimidazoles (4) in high yields. The novel ring transformation of 1 into 3 occurs via a regioselective attack of ammonia on the C-2 position of the ring.
美索离子4-三氟乙酰基-1,3-噁唑啉-5-醇盐(1)是由N-酰基-N-烷基甘氨酸(2)与三氟乙酸酐反应得到的,能够与氨反应生成4-三氟甲基-3,4-二氢咪唑(3),产率高。3的脱水反应高产率地生成4-三氟甲基咪唑(4)。1到3的这一新颖环转换过程是通过氨对环C-2位点的区域选择性攻击实现的。