PREPARATION OF DARIFENACIN AND ITS SALTS

摘要

Provided are various processes and compounds related to darifenacin and/or its salts. For example, there is provided a process for preparing a free base of darifenacin: Formula, or the salt thereof, the process including reacting 3-(S)-(cyanodiphenylmethyl)-1-[2-(2,3-dihydrobenzofuran-5-yl) ethyl] pyrrolidine of the Formula (IV), or a salt thereof: Formula (IV) with a base effective to convert the nitrile group of the compound of the Formula (IV) to the amide group of the darifenacin in an organic solvent, the reaction being carried out in the organic solvent, with a proviso that the solvent is not 2-methyl-butan-2-ol, and with further proviso that the reaction produces less than about 0.5 % of the compound of the Formula (Ic): Formula (Ic) in the reaction mass, as measured by HPLC. Various embodiments and variants are provided.