METHOD FOR THE PRODUCTION OF 6,7-DIMETHOXY-4-AMINO-2- (4-(2-FUROYL)-1-PIPERAZINYL) QUINAZOLINE HAVING AN ANTIHYPERTENSIVE EFFECT

摘要

A novel process is provided for the preparation of 6,7-dimethoxy-4-amino-24-(2-furoyl)-1-piperazinyl!quinazoline. It includes as a final step, cyclizing methyl-N-(3,4-dimethoxy-6-cyanophenyl)-4-(2-furoyl)-1-piperazinyl! thioformamidate by heating, together with ammonia, in a polar solvent, in the presence of an alkali metal amide. The methyl-N-(3,4-dimethoxy-6-cyanophenyl)-4-(2-furoyl)-1-piperazinyl!thio formamidate is preferably formed by reacting 3,4-dimethoxy-6-4-(2-furoyl)-1-piperazinyl-thiocarbamido!benzonitrile with methyl chloride. By this process the quinazoline ring in prazosine is produced within the molecule, rather than in a reaction between two different molecules.