Alkyl-3-(2-quinoxalinylmethylene)- carbazate-1,4-dioxide prodn - by reacting methyl carbazate with hydrazones of 2-formylquinoxaline-1,4-dioxide

摘要

Process for prodn. of alkyl-3-(2-quinoxalinylmethylene)-carbazate-1,4-dioxide (I) by reacting (a) methyl carbazate (II) with (b) the hydrazone of 2-formylquinoxaline-1,4-dioxide (III) or the symmetrical hydrazone of 2-formaylquinoxaline-1,4-dioxide (IV): Use of the hydrazones (II) and (III) in place 2-formylquinoxaline-1,4-dioxide (V) as in prior art processes gives higher yields of (I), with reduced darkening of the prod. and simplifies purification of the prod.