5-氨基噻吩四乙酯的相转移催化合成

Synthesis of Tetraethyl Ester of 5-Aminothiophene by Phase Transfer Catalysis

目的研究了5-氨基噻吩四乙酯的相转移催化合成,并考查最佳催化条件。方法以氧代戊二酸二乙酯为原料,环合生成5-氨基噻吩,再以冠醚为相转移催化剂,溴乙酸乙酯为烷基化试剂,碳酸钾为固体碱,在丙酮中进行烷基化催化反应。结果该催化反应的最佳条件:以冠醚为催化剂,烷基化试剂与固体碱对反应物的摩尔比分别为2.2与2.5,反应温度为60℃(水浴温度),反应时间为6 h。结论此催化反应不良反应少、收率好、纯度高。

OBJECTIVE Synthesis of tetraethyl ester of 5-aminothiophene by phase transfer catalysis was studied, and the best catalysis condition was also examinated. METHODS First,5-aminothiophene was synthesized from diethyl acetone-1,3-dicarboxylate by cyclization. Then in acetone, tetraethyl ester of 5-aminothiophene was synthesized from 5-aminothiophene by phase transfer catalysis with ethyl bromoacetate in presence of crown ether using potassium carbonate as solid base. RESULTS The best condition of catalysis was that using crown ether as phase transfer catalyzer, the molar ratio of alkylating reagent, alkali and reagent was 2. 2 and 2.5 respectively, the reaction temperature was 60 ℃ and the time of the reaction was 6 h. CONCLUSION There were many advantages with little side reaction, great yield, and high pure. It was the key preparation for getting high pure strontium ranelate.