Hydrogen Bromide → Darifenacin

Participants

Reaction Steps

Pd/C 10% (0.8 g) was added to a solution of S)-2-{1-[2-(benzofuran-5-yl)ethyl]-3-pyrrolidinyl}-2,2-diphenylacetamide (8 g) in acetic acid (160 ml). The mixture was hydrogenated at 45-50° C. and at atmospheric pressure for about 6-7 hrs. Catalyst was filtered off and solution was concentrated under vacuum obtaining an oily residue. n-Butanol (40 ml) was added and stirred to obtain a solution. 48% HBr (3.5 g) was added and a mixture n-Butanol/water was eliminated by distillation to reduce water content to less then 1%. Darifenacin .HBr crystallizes and after 2 hrs at 15-20° C. was filtered and washed with n-Butanol (3×5 ml). After drying at 55-60° C. under vacuum 8.1 g of Darifenacin hydrobromide were obtained. (Yield 85%).

Provenance & Evidence