Sulfuric Acid → Clopidogrel Bisulfate

Participants

Reaction Conditions

Reaction Steps

Clopidogrel base (250 gms) was dissolved in n-hexanol (1.25 L) with stirring at 25 to 30° C. Dilute sulfuric acid was added at 10 to 15° C. The reaction mixture was seeded with form-I crystals at 20 to 25° C. The reaction mixture was stirred at room temperature, for 10-12 hrs and subsequently it was stirred at 22 to 25° C., for 1-3 hours at high agitation. The reaction mixture was further stirred for 5-8 hours at a room temperature at low agitation. It was then filtered, washed with methyl tert butyl ether (750 ml) and dried at 30 to 35° C. in a drier, to obtain 240 g of clopidogrel bisulfate salt. Subsequent analysis confirmed that the crystals were clopidogrel hydrogen sulfate Form-I.

Provenance & Evidence