(CAS NO.: ), with its systematic name of 1-(4-Amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furoyl)piperazine monohydrochloride, could be produced through many synthetic methods.

Following is one of the synthesis routes:

Treatment of carboxy polystyrene resin (I) with oxalyl chloride in dichloromethane, followed by reaction with Bu₄NNCS in THF/DCM, affords isothiocyanate resin (II), to which 2-amino-4,5-dimethoxybenzonitrile (III) is attached by means of NMP to provide derivative (IV). Treatment of resin (IV) with 1-(2-furoyl)-piperazine (V) and EDC in chloroform in the presence of DIEA furnishes resin-bound guanidine (VI), from which prazosin is obtained as its trifluoroacetic acid salt (VII) by acidolysis with TFA/H₂O at 80 C. At last, the hydrochloride salt of prazosin can be obtained by treatment with HCl.