| abstract |
The present invention relates to an improved process for the preparation of Darifenacin hydrobromide of Formula (I). (i) condensing 3-(S)-(-)-1l-carbamoyl-1,1-diphenylmethyl)pyrrolidine (III), or its salt, with a compound of Formula XIII in the presence of a. base in a solvent, wherein X represents Cl, Br, C 1-3 alkyl sulfonate or C 6-10 arγl sulfonate; to produce (S)-2-[1-[2-(2,3-dihydrobenzofuran-5-yl)ethyl]-3- pyrrolidinyl]-2,2-diphenylacetamide (Darifenacin) (Ia), (ix) treating (S)-2-[1-[2-(2,3-dihydrobenzofuran-5-yl)ethyl]-3-pyrrolidinyl]- 2,2-diphenylacetamide (Darifenacin) (Ia) with an acid in a solvent and water mixture, (x) isolating pure (S)-2-[1-[2-(2,3-dihydrobenzofuran-5-yl)ethyl]-3- pyrrolidinyl]-2,2-diphenylacetamide (Darifenacin) (Ia), (xi) treating pure Darifenacin (Ia) with HBr to produce Darifenacin hydrobromide (I). |