4-羟基香豆素的合成工艺改进

Improvement in process for synthesis of 4-hydroxycoumarin

以邻羟基苯乙酮与碳酸二甲酯为原料,甲醇钠与聚乙二醇-400为催化剂合成了标题化合物,考察了甲醇钠用量、聚乙二醇-400用量、反应时间、反应温度等因素对反应结果的影响。确定最佳工艺条件为：以二甲苯为溶剂,原料物质的量比为：n（邻羟基苯乙酮）∶n（碳酸二甲酯）∶n（甲醇钠）∶n（聚乙二醇-400）=1∶2.0∶2.5∶0.28,120℃反应2 h,反应结束后加水,水相酸化至pH1.0~1.5,4-羟基香豆素的收率56.9%。产物经熔点、IR、1HNMR、13CNMR进行确认。

4-Hydroxycoumarin was synthesized via the reaction of 2-hydroxyacetophenone with dimethyl carbonate using sodium methoxide and polyethylene glycol-400 as the catalytic system.The factors,such as the dosage of sodium methoxide and polyethylene glycol-400,the reaction time and the reaction temperature,had been investigated.The optimal reaction conditions using xylene as the solvent were as follows：the ratio of n（2-hydroxyacetophenone）∶n（dimethyl carbonate）∶n（sodium methoxide）∶n（polyethylene glycol-400）=1∶2.0∶2.5∶0.28.The reaction mixture was heated at 120 ℃ for 2 h.Then the aqueous phase was acidified to a pH value of 1.0～1.5 after addition of water to the reaction mixture.4-Hydroxycoumarin was produced in 56.9% yield.The product was characterized by melting point measurements,IR,1HNMR and 13CNMR.