3,4-二羟基钠-2,5-二甲酸二乙酯噻吩的合成

以硫代二甘酸二乙酯和草酸二乙酯为原料,乙醇为溶剂,在乙醇钠的作用下,经Claisen酯缩合反应制备3,4-二羟基钠-2,5-二甲酸二乙酯噻吩。研究了物料配比、反应温度、反应时间及加料方式对反应速率及产物收率的影响。较佳反应条件为:n(硫代二甘酸二乙酯)∶n(草酸二乙酯)∶n(乙醇钠)=1∶1.25∶2.5,将硫代二甘酸二乙酯、草酸二乙酯与60mL乙醇的混合物滴加到溶有乙醇钠的240mL乙醇中,反应温度78℃,反应时间4h,3,4-二羟基钠-2,5-二甲酸二乙酯噻吩的收率达98.4%,纯度99.5%以上。

SYNTHESIS OF DISODIUM 2,5-DICARBOXYLIC ACID DIETHYL-3,4-DIHYDROXYTHIOPHENE

Disodium 2,5-dicarboxylic acid diethyl-3,4-dihydroxythiophene was efficiently synthesized via the Claisen condensation of diethyl thiodiglycolate with diethyl ethaneioate in the presence of sodium ethoxide.The effects of the molar ratios of diethyl thiodiglycolate to diethyl ethaneioate to sodium ethoxide,feeding manner,reaction temperature and reaction time on the reaction rate and the product yield were investigated.The yield of disodium-2,5-dicarboxylic acid diethyl-3,4-dihydroxythiophene reached 98.4% with the purity above 99.5% when the reaction was carried out with the molar ratio of diethyl thiodiglycolate to diethyl ethaneioate to sodium ethoxide of 1∶1.25∶2.5 at 78 ℃ for 4 h,with the addition of the mixture of diethyl thiodiglycolate(0.24 mol),diethyl ethaneioate and ethanol(60 mL) into 240 mL of ethanol solution of sodium ethylate.