均相催化合成2-吡咯甲酸甲酯

以碳酸二甲酯(DMC)为甲氧基羰基化试剂,考察了不同碱金属卤化物对吡咯直接甲氧基羰基化反应合成2-吡咯甲酸甲酯(2-MPC)的影响。实验结果表明,只有 KI 催化吡咯进行甲氧基羰基化反应时合成了2-MPC。用荧光光谱对催化剂与反应物的相互作用进行表征,结果发现,碱金属卤化物以离子对的方式与反应物相互作用,卤素阴离子和金属阳离子同时起催化作用,它们与吡咯的作用影响吡咯的转化率,与 DMC 的作用则影响吡咯甲氧基羰基化产物的选择性。以 KI 为催化剂的适宜反应条件为:反应温度200℃、反应时间3 h、n(DMC):n(吡咯)=4、KI 用量(相对于吡咯的摩尔分数)为5.68%。在此条件下,吡咯的转化率为42.80%,2-MPC 的选择性和收率分别为46.08%和19.72%。

Synthesis of Methyl Pyrrole-2-Carboxylate by Homogeneous Catalysis

Methyl pyrrole-2-carboxylate(2-MPC) was successfully synthesized from pyrrole and dimethyl carbonate (DMC) by direct methoxycarbonylation with alkali metal halides as catalysts. Catalytic performances of different alkali metal halides in methoxycarbonylation of pyrrole showed that 2-MPC could be produced only with KI,although all others can give sole methoxycarbonylation product of methyl pyrrole-1-carboxylate.The interaction between catalyst and reactants in the reaction was further investigated by fluores...