合成5-氯-1-甲基-4-硝基咪唑的工艺改进

Process Improvement on the Synthesis of 5-Chloro-1-methyl-4-nitroimidazole

以草酸二乙酯为原料,经酰胺化、环合、成盐及硝化反应合成了5-氯-1-甲基-4-硝基咪唑,总收率61.3%,其结构经1H NMR,IR和MS表征。本方法有两点改进:(1)在酰胺化反应中用30%～40%甲胺水溶液代替甲胺气体;(2)在成盐反应中直接向环化产物的丙酮溶液加硝酸析出5-氯-1-甲基咪唑硝酸盐晶体。

5-Chloro-1-methyl-4-nitroimidazole in overall yield of 61.3 % was synthesized from diethyl ethaneioate by a four-step reaction of amination, cyclization, salt formation, and nitration. The structure was characterized by NMR, IR and MS. Two improvements were that 30% - 40% methylamine aqueous solution was substituted for methylamine gas in amination, and crystal of 5-chloro-1-methy- limidazole nitrate was separated out by adding nitric acid into acetone solution of cyclization product in salt formation.