PREPARATION OF ISOXAZOLE-4,5-DICARBOXYLIC DIESTERS

摘要

A process for preparing novel isoxazole-4,5-dicarboxylic diesters of the formula I (see formula I) where R1 is an aliphatic radical of 1 to 20, cycloaliphatic radical of 3 to 10, aromatic radical of 6 to 10, heteroaromatic or heterocyclic radical of 3 to 10 or araliphatic radical of 4 to 12 carbon atoms, each radical being unsubstituted or substituted by substituents which are inert under the reaction conditions, and where R2 and R3 are each alkyl, comprises reacting an aldoxime of the formula II (see formula II) with an acetylenedicarboxylic diester of the formula III R2OOC-C~C-COOR3 (III) in solution, in the presence of an aqueous solution of a hypohalite in the pH range from 5 to 10.