Process and intermediate for the preparation of terazosin hydrochloride dihydrate

摘要

A process for the preparation of 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-tetrahydrofuroyl)piperazine hydrochloride (terazosin hydrochloride dihydrate comprises the steps of reacting 4-amino-2-chloro-6,7-dimethoxy-quinazoline with N-(2-tetrahydrofuroyl)piperazine in an anhydrous polar organic solvent in the absence of an added acid scavenger to produce anhydrous 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-tetrahydrofuroyl)piperazine hydrochloride (Form IV) and thereafter converting the product of that step to 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-tetrahydrofuroyl)piperazine hydrochloride dihydrate.