1,4-benzothiazine derivatives from 2-aminobenzenethiol and hydrazonoyl halides

2-Aminobenzenethiol was condensed with alkyl α-chlorophenylhydrazonoglyoxylates yielding alkyl 2-(2-aminophenylthio)-2-arylhydrazonoglyoxylates which were cyclized to the corresponding 2-arylhydrazono-2,3-dihydro-4H-1,4-benzothiazin-3-ones. Starting from α-chloro-α-arylhydrazonoacetones the corresponding 2-arylhydrazono-3-methylbenzo-1,4-benzothiazines were formed.