PROCESS FOR PREPARING SUBSTITUTED OXADIAZOLONES.

摘要

Substituted oxadiazolones of the formula (I) (I) in which R represents optionally substituted alkyl, are obtained in good yields and high purity on reacting in a first step carboxylic acids of the general formula (II)R-COOH(II)with hydrazine hydrate in the presence of a catalyst and an inert diluent at temperatures between 0 DEG C. and 150 DEG C. with elimination of water and removal of said catalyst and reacting the resulting carboxylic hydrazides of the general formula (III)R-CO-NH-NH2(III)in a second step with phosgene (COCl2) at temperatures between 20 DEG C. and 120 DEG C.