ABSTRACT OF THE DISCLOSUREA novel process is provided for the preparation of 6,7-dimethoxy-4-amino-2[4-(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 thepresence of an alkali metal amide. The methyl-N-(3,4-dimethoxy-6-cyanophenyl)-[4-(2-furoyl)-1-piperazinyl]thioformamidate is preferably formed by reacting3,4-dimethoxy-6-[4-(2-furoyl)-1-piperazinyl-thiocarbamido]benzonitrile with methylchloride. By this process the quinazoline ring in prazosine is produced withinthe molecule, rather than in a reaction between two different molecules.
展开▼
