Sulfuric Acid → Clopidogrel Bisulfate

Participants

Reaction Conditions

Reaction Steps

Clopidogrel base (925 gms) was dissolved in n-hexanol (4.6 L) with stirring at 25 to 30° C. Dilute sulfuric acid was added to the reaction mixture at 10 to 15° C. The mixture was seeded with form-I crystal at 20 to 25° C. The reaction mixture was stirred for approximately 8 to 10 hours & subsequently further stirred for 8-10 hrs at 22 to 25° C. with low agitation. The solid was then filtered and washed with methyl tert butyl ether (1875 ml) and subsequently dried at 30 to 35° C. on a drier, to get 1095 g of clopidogrel bisulfate salt as crystals. Subsequent analysis confirmed that the crystals were clopidogrel hydrogen sulfate Form-I.

Provenance & Evidence