Patent ID: 9272982
Filing Date: 2016-03-01
CPC Classification: C07C

Claim Text:
1. Method for preparing fesoterodine fumarate having a content of (2E)-4-[(3-(3-diisopropylamino-1-phenylpropyl)-4-(2-isobutyroyloxyphenyl)methoxy]-4-oxobut-2-enoic acid less than or equal to 0.15% by mole, said method comprising: reacting fesoterodine with fumaric acid in at least one organic solvent, wherein said reacting step is carried out at a temperature not higher than 45° C., thereby obtaining fesoterodine fumarate having a content of (2E)-4-[(3-(3-diisopropylamino-1-phenylpropyl)-4-(2-isobutyroyloxyphenyl)methoxy]-4-oxobut-2-enoic acid less than or equal to 0.15% by mole, wherein said fesoterodine is used in a g/l weight/volume ratio comprised between 2:1 and 50:1 with respect to said at least one organic solvent.