The reduction of 2,3-dimethyl-4-(o-nitrophenylthio)-1-phenyl-3-pyrazolin-5-one by sodium borohydride and palladium–charcoal gave the corresponding hydroxylamine. The action of hydrochloric acid on this hydroxylamine gave thep-chloroamine. In a similar manner, treatment of some 2H-1,4-benzothiazine and -benzoxazine hydroxamic acids with hydrochloric acid resulted in the formation of 7-chloro-2H-1,4-benzothiazine and -benzoxazine lactams.