Substituted 3-phenyl-7H-thiazol[3,2-b][1,2,4]-triazin-7-ones

A substituted 3-phenyl-7H-thiazolo[3,2,b][1,2,4]triazin-7-one of the formula I ##STR29## in which R.sup.1 is a straight-chain or branched alkyl group having 1 to 4 carbon atoms, hydroxymethyl or an aminomethyl group of the formula II ##STR30## R.sup.2 is a hydrogen atom or an alkyl radical having 1 to 3 carbon atoms, and

• R.sup.3 is a hydrogen atom, a straight-chain or branched alkyl group having 1 to 4 carbon atoms, hydroxymethyl or an aminomethyl group of the formula II, where
• R.sup.4 and R.sup.5 are identical or different and are a hydrogen atom or a straight-chain or branched alkyl radical having 1 to 4 carbon atoms, or the two radicals, together with the nitrogen atom to which they are bound, form a heterocyclic ring selected from the group consisting of pyrrolidino, piperidino, hexamethyleneimino, morpholino, thiomorpholino, piperazino and homopiperazino, whereby said piperazino and homopiperazino rings can be alkylated on their second nitrogen atom with (C.sub.1 -C.sub.4) alkyl, or a physiologically acceptable acid-addition salt of the compound having the structural element of the formula II in the positions of R.sup.1 and/or R.sup.3.