Processes for preparing cilostazol (6-[4-(1-cyclohexyl- 1H-tetrazol-5-yl)butoxy]-3,4-dihydro-2(1H)-quinolinone)

摘要

Processes for preparing 6-[4-(1-cyclohexyl-1H-tetrazol- 5-yl)butoxy]-3,4-dihydro-2(1H-quinolinone of formula (I) which is also known by the generic name cilostazol are disclosed, wherein a process for preparing cilostazol of formula (I) comprises: (a) dissolving 6-hydroxy-3,4-dihydroquinolinone and a water- soluble base in water to form an aqueous phase, (b) dissolving a 1-cyclohexyl-5-(4-halobutyl)-tetrazole in a water-immiscible solvent to form an organic phase, (c) forming a biphasic mixture by contacting the aqueous phase and the organic phase in the presence of a quaternary ammonium phase transfer catalyst, (d) and recovering cilostazol from the biphasic mixture. Cilostazol inhibits cell platelet aggregation and is used to treat patients with intermittent claudication.