2-乙氧羰基-3-甲基-4,5-四亚甲基吡咯的合成

以乙酰乙酸乙酯(1)为原料,在醋酸中与亚硝酸钠通过肟化反应制得N-羟基亚胺乙酰乙酸乙酯(2);2在醋酸缓冲溶液中经锌粉还原后与环己酮加成环化合成了2-乙氧羰基-3-甲基-4,5-四亚甲基吡咯(3),其结构经1H NMR,IR和元素分析表征。较适宜的反应条件为:1100 mmol,n(Zn)∶n(1)=2.9∶1.0,在醋酸中回流反应,总收率39%;以多步反应的最佳反应条件进行一锅煮合成3,收率50%。

Synthesis of 2-Ethoxycarbonyl-3-methyl-4,5-tetramethylenepyrrole

N-hydroxyimino ethyl acetoacetate(2) was prepared by oximation of ethyl acetoacetate(1) with NaNO_2 in acetic acid.2 was reduced by zinc dust,and then cyclized by addition to cyclohexanone in acetate buffer solution to obtain 2-ethoxycarbonyl-3-methyl-4,5-tetramethylenepyrrole(3).The appropriate reaction conditions at reflux were as follows:1 was 100 mmol,n(Zn):n(1) was 2.9:1.0.The total yield was 39% under the conditions.The structure of 4 was characterized by ~1H NMR,IR and elemental analysis.3 in yield of 50% was synthesized by one-pot method under the conditions.