摘要 |
A process is described for preparing fesoterodine and/or fesoterodine fumarate comprising the esterification of (R)-feso deacyl with isobutyric acid or a precursor thereof, such as an isobutyryl halide or the isobutyric acid anhydride to give fesoterodine, in a mixture of water at alkaline pH and/or at least one organic solvent. This process allows obtaining products with high yields and purities, and in particular a product having a content of (R)-2-[3-(diisopropylamino)-1-phenylpropyl]-4-isobutyroyloxymethyl-phenyl isobutyrate less than 1% by mole and a content of (R)-2-[3-(diisopropylamino)-1-phenylpropyl]-4-(hydroxymethyl)phenol less than 0.05% by mole.
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