PREPARATION OF 4-AMINO-(6,7-DI-OR 6,7,8-TRI)-METHOXY-2-(4-SUBSTITUTED PIPERAZIN-1-YL)-QUINAZOLINES AND CERTAIN 4-SUBSTITUTEDAMINO QUINAZOLINE PRECURSORS THERETO

摘要

Compounds of the formula IMAGE or of a hydrochloric or hydrobromic acid addition salt thereof, in which R1 is hydrogen or methoxy, and R2 denotes benzoyl, furoyl, thienylcarbonyl, alkoxycarbonyl having 2 to 5 carbon atoms or (2-hydroxyalkoxy)carbonyl having 4 or 5 carbon atoms, are prepared in accordance with a novel process. Initially, a 2-chloro-6,7-dimethoxyquinazoline or a 2-bromo-6,7-dimethoxyquinazoline, whose amino group situated in the 4 position is substituted, is reacted, in an inert organic solvent and at 50-200 DEG C, with a corresponding piperazine. In a second reaction step, the substituents of the amino group are removed by hydrogenolysis. The compounds which are obtained can be used as agents for lowering blood pressure.