Ethyl chloroformate → Cisapride (USP/INN)

Participants

Reaction Steps

To a solution of 4-amino-5-chloro-2-methoxybenzoic acid (20.2 g) in MIK (250 ml) and triethyl amine (15.3 ml) was slowly dropped ethyl chloroformate (9.6 ml). The reaction mixture was stirred for 30 minutes at room temperature. To the formed mixed anhydride was then added intermediate 2 (28.2 g) and the reaction mixture was stirred for 2 hours at room temperature. Subsequently, the reaction mixture was washed with water (80 ml) and a NaOH solution (6.5% w/v, 50 ml). The organic layer was warmed to 65° C. and methanol (50 ml) and water (8.5 ml) were added. The solution was cooled slowly and stirred for 2 days during which crystallisation occurred, yielding cisapride having a cis/trans ratio higher than 99/1.

Provenance & Evidence