Potassium Carbonate → Cilostazol

Participants

Reaction Conditions

Reaction Steps

Into a reaction vessel having a capacity of 500 mL were introduced 6-hydroxy-3,4-dihydrocarbostyril (30 g, 0.18 mol), 1-cyclohexyl-5-(4-chlorobutyl)-1,2,3,4-tetrazole (49.09 g, 0.20 mol, 1.1 M), potassium carbonate (55.90 g, 0.40 mol, 2.2 M), sodium hydroxide (5.88 g, 0.15 mol, 0.8 M), sodium sulfite (1.5 g, 0.01 mol) and purified water (150 ml). The mixture of the reactants was heated at about 92° C. for about 6 hours with circulating by continuous disperser (pipeline homomixer T.K.ROBO MIX manufactured by TOKUSHUKIKA KOGYO CO. LTD.). After the completion of the reaction, the reaction mixture was cooled to around 50° C., and the mixture was introduced into a flask having a capacity of 1 L, methanol (150 mL) was added thereto and the resulting reaction mixture was refluxed with heating for about 2 hours. The mixture was cooled to the ambient temperature and the precipitated crystalline product was collected by filtration and washed with purified water (150 mL), methanol (90 mL), followed by purified water (150 mL), then dried at about 80° C. Thus, 62.14 g of cilostazol was obtained. Yield: 91.48%, Purity: 99.66%, m.p.: 158–159° C.

Provenance & Evidence