Diisopropyl Ether → Fesoterodine fumarate

Participants

Reaction Steps

A 7% solution of aqueous NaHCO3 (25 ml) was added to a suspension of Fesoterodine Hydrochloride monohydrate (5 g) in dichloromethane (50 ml) at 10-15° C. The resulting mixture was stirred at room temperature and the two phases were separated. The organic phase was evaporated under reduced pressure; acetone (10 ml) was added twice and evaporated under reduced pressure to afford a Fesoterodine base solution. The Fesoterodine base solution was added over an acetone/fumaric acid suspension (10 ml/1.25 g) at 15-20° C. Diisopropyl ether 5 ml was added at 10-15° C. and the suspension was stirred to allow crystallization for 1-2 h, then diisopropyl ether 5 ml was added and the suspension stirred for 1-2 h. Finally diisopropyl ether (30 ml) was added and the suspension stirred for another 1-2 h. The suspension was filtered off and the crystallized product was washed with acetone/diisopropyl ether (10 ml), to yield 5.1 g of the corresponding Fesoterodine Fumarate.

Provenance & Evidence