Potassium Carbonate → Cilostazol

Participants

Reaction Steps

A mixture of 10 grams of 6-hydroxy-3,4dihydroquinolin-2(1H)-one (Compound I, 0.0613 mole), 4.05 grams of flaked potassium hydroxide (0.0650 mole) and 1.5 grams of K2CO3 (0.011 mole), was stirred in 130 ml of 1-botanol in a flask equipped with a soxhlet extraction apparatus containing 28 grams of 3 Å molecular sieves. The mixture was heated to reflux while passing the solvent over the molecular sieves for 30 minutes. Thereafter 18 grams of 5-(4-chlorobutyl)-1-cyclohexyl-1H-tetrazole (Compound II, 0.0742 moles, which are 1.2 equivalents with respect to Compound I) were added and the reflux was allowed to continue for about 5 hours. The reaction mixture was cooled thereafter to room temperature, and the solid product was collected by filtration, washed with 1-butanol and water and dried at 50° C. overnight to afford 19.2 grams of crude Cilostazol at 70.0% yield.

Provenance & Evidence