Process for the manufacture of vat dyes

A process for the manufacture of vat dyes of the formula ##STR31## wherein each of A.sub.1 and A.sub.2 independently is an anthrapyrimidine, anthrapyridone, anthrapyrimidone, azabenzanthrone, benzanthrone, anthrone, anthrimide, anthrimidecarbazole, isothiazoleanthrone, pyrazole-anthrone, pyrimidanthrone, quinazolineanthraquinone, oxazole-anthraquinone, thiazole-anthraquinone, oxadiazole-anthraquinone, pyrazole-anthraquinone, pyrazino-anthraquinone, anthraquinone or phthaloyl-acridone radical which can carry as substituents halogen atoms, alkyl, alkoxy, aryl, aryloxy, aralkyl, aralko arylamino, alkylmercapto, arylmercapto, cyano, thiocyano, acyl, acylamino, carbalkoxy, sulfonamide and carboxyamide groups, which comprises reacting compounds of the formula ##STR32## wherein X is halogen and A.sub.1 and A.sub.2 are as defined for formula (1), in a basic medium with hydrazine, hydrazine hydrate, methyl hydrazine, ethyl hydrazine, phenyl hydrazine, hydrazinium chloride, hydrazinium dichloride, hydrazinium sulfate, hydrazinium bromide or benzenesulfonyl hydrazide.