2-(4-溴甲基苯基)丙酸及其酯的合成

Synthesis of 2-(4-bromomethylphenyl) propionic acid and ester

以对甲苯苯乙腈为原料经甲基化、水解和溴代3步反应合成了2-(4-溴甲基苯基)丙酸和以对甲基苯乙酸乙酯为原料经甲基化和溴代两步合成2-(4-溴甲基苯基)丙酸乙酯。重点探讨了甲基化反应的反应时间及不同相转移催化剂聚乙醇(PEG)对反应的影响。实验结果表明,甲基化反应以8 h为宜,对甲基苯乙腈和对甲苯苯乙酸乙酯甲基化反应的最佳温度分别为180和220℃,前者以碳酸钾与PEG-400共同催化效果较佳,后者以碳酸钾与PEG-600共同催化效果较佳。该两种合成方法收率分别为67.6%和74.8%。

2-（4-Bromomethylphenyl） propionic acid was synthesized from p-methybenzyl cyanide via methylation,hydrolysis and bromide reaction and ethyl 2-（4-bromomethylphenyl）propionate was synthesized from ethyl p-tolylacetate via methylation and bromide reaction.The influences of reaction time and phase transfer catalyst PEG were discussed on methylation.The result indicates that the optimum reaction time is 8 h for methylation,the optimum reaction temperature is 180 ℃ for p-methybenzyl cyanide and 220 ℃ for ethyl p-tolylacetate.The catalytic effect of methylation was obtained optimally with the synergistic catalysis of K2CO3 and PEG-400 for the former and the synergistic catalysis of K2CO3 and PEG-600 for the latter.Yield of the former from p-methybenzyl cyanide is 67.6% and yield of the latter from Ethyl p-tolylacetate is 74.8%.