Synthesis of 2-Ethoxycarbonyl-3-Methyl-4,5-Tetramethylenepyrrole

N-hydroxyimino ethyl acetoacetate(2) was prepared from ethyl acetoacetate(1) and NaNO2 via oximination using acetic acid instead of vitriol as reaction medium,and compound 2 was reacted with cyclohexanone(3) by means of reduction of zinc dust and addition-cyclization in buffered acetic acid solvent to give 2-ethoxycarbonyl-3-methyl-4,5-tetramethylenepyrrole(4) with an about 38.95% overall yield.However,the total yield of compound 4 prepared by one-pot method reached a maximum of 49.76%.The effects of some other reaction conditions on the yield of object compound 4 were examined when the pH of the above mentioned reaction system is in the range of from 3.8 to 4.0,and the optimum reaction conditions were determined as follows:the molar ratio of zinc powder to compound(1) was 2.9:1 and the reaction temperature is set as 95～100 ℃.The structures of the obtained compounds were characterized by elemental analysis,IR,1HNMR,et al.