Clopidogrel → Clopidogrel 2-naphthalenesulfonate

Participants

Reaction Steps

50 g of clopidogrel free base having an optical purity of 99.3% ee which was prepared by the method similar to that disclosed in International Patent Publication No. WO 02/59128 was dissolved in 100 ml of ethyl acetate, and a solution containing 34.8 g of 2-naphthalenesulfonic acid monohydrate dissolved in a mixture of 150 ml of ethyl acetate and 5 ml of water was added thereto dropwise over a period of 30 minutes. Then, the mixture was stirred at room temperature for 12 hours, and then, at a temperature ranging from 0 to 5 for 4 hours. The precipitates formed were filtered, washed with 30 ml of ethyl acetate and dried at 50° C., to obtain 71.6 g of the title compound (yield: 87%) as an white crystal.

Provenance & Evidence