烃氧基丙二酸酯的新制备方法

A New Method for the Preparation of Alkoxymalonic Esters

烃氧基丙二酸酯在有机合成中是有用的试剂,一般来讲,实验室的四类制备方法都有不足之处:(1)烃氧基乙酸酯与草酸酯或碳酸酯之间的酯缩合反应。此法虽使用最广,但使用草酸酯的方法中,脱羰反应往往不完全,并且烦琐,而使用碳酸酯,因其反应性较差,也常影响制备的结果。

Alkoxymalonic esters are useful reagents in organic syntheses, but most, of the methods for their preparation found in the literatures[1-7] are of restricted applications, and in some of these methods the yields are unsatisfactory, the starting materials are not readily available, or the procedures for preparation are somewhat tedious. In order to improve such a situation, a general applicable new method with a good yield (mostly over 75%) has been proposed. The reaction is carried out with an alcohol ROH (or a phenol) and an alkyl (R’) bromomalonate in the presence of triethylamine where R’ should be equal to R for preventing transesterification and mixed alkoxylation. But ethyl bromomalonate is quite feasible in the preparation of phenoxymalonate because transesterification product has not been isolated.