1-Isoquinolinol was synthesized from isoquinoline via oxidation, reaction with benzoyl chloride and water in yield of 73.3%. According to this process, a method for the synthesis of hydroxyfasudil [1-(1-hydroxy-5-isoquinolinesulfonyl)- homopiperazine] from fasudil [hexahydro-1-(5-isoquinoline-sulfonyl)-1H-1,4-diazepine] was estabilshed in this paper. The process undergoes effectively through protection for amino, oxidation, reaction with water in a water/dichloromethane biphase system in the presence of phase transfer catalyst and benzoyl chloride and then deprotection. The objective product was finally obtained in yield of 46.8% with a purity more than 99% (HPLC). It is virtually a practical process with mild reaction conditions and simple operation.

Key words: 1-isoquinolinol, nitrogen oxide, fasudil, hydroxyfasudil