Verfahren zur Herstellung therapeutisch wirksamer 1,2-Dihydro-1,2,4-benztriazine

Novel compounds represented by the general formula and pharmaceutically acceptable acid addition salts thereof, wherein X1 and X2, which may be the same or different are each hydrogen, halogen, a lower alkyl group or an unsubstituted or substituted amino radical; Y represents an unsubstituted or substituted amino radical including a heterocyclic amine radical, or a lower alkoxy group; and Z1 and Z2, which may be the same or different, are each hydrogen or an acyl radical or together represent the two acyl radicals of a dicarboxylic acid which may be substituted by a C1- 5 alkyl group or a cycloalkyl group, are obtained by treating a 1,2,4-benztriazine-1-oxide having the formula wherein X1, X2, and Y have the meanings above, with a reducing agent and isolating the reduction product so obtained as an acid addition salt, or when a compound in which both Z1 and Z2 are not both hydrogen is required, acylating the reduction product with an appropriate acylating agent and isolating the product so obtained.