噻吩-2，5-二甲酸及其酯的催化合成

Catalytic Synthesis of Thiophene-2, 5-dicarboxylic Acid and its Esters

摘要:

以醋酸亚铁为催化剂，噻吩与四氯化碳、甲醇或乙醇回流反应合成了噻吩-2, 5-二甲酸二甲酯 (1a)或噻吩-2, 5-二甲酸二乙酯 (1b)，较佳的反应条件是：n (噻吩)：n (四氯化碳)：n (醋酸亚铁)＝1: 2.5: 0.01，在过量的醇中回流6 h, 产率为91.5%~95.2%。化合物1a或1b经碱性条件下水解、酸化合成了噻吩-2, 5-二甲酸 (2)，较佳的反应条件是：n (噻吩-2, 5-二甲酸酯): n (氢氧化钠)=1: 2.5，在体积比为1: 2甲醇-水溶剂中回流5 h，产率为90.5%~92.0%。

Abstract:

Thiophene was refluxed with carbon tetrachloride and methanol or ethanol to give dimethyl thiophene-2, 5-dicarboxylate (1a) or diethyl thiophene-2, 5-dicarboxylate (1b) using Ferrous acetate as catalyst. The optimum conditions were n (thiophene)：n (carbon tetrachloride)：n (ferrous acetate)＝1: 2.5: 0.01 and reflux time 6 h in excess alcohol. Yields of thiophene-2, 5-dicarboxylate were 91.5%~95.2%. Compound 1a or 1b was hydrated in base condition and then acidified to give thiophene-2, 5-dicarboxylic acid (2). The optimal reaction conditions were n (thiophene-2, 5-dicarboxylate): n (sodium hydroxide)=1: 2.5 and reflux time 5 h in methanol and water (1: 2). Yields of thiophene-2, 5-dicarboxylic acid were 90.5%~92.0%.