Patent ID: 7238839
Filing Date: 2007-07-03
Classification: C07B,C07C

Abstract:
1. A process to obtain solid R-tamsulosin free base or a salt the thereof, said process comprising the steps of: (a) mixing a racemic mixture of tamsulosin or salts thereof and S-BPA in a medium comprising an organic solvent and optionally water to provide a first mixture; (b) maintaining the first mixture at a temperature from 20° to 60° C. for a period from 2 to 10 hours to provide a second mixture comprising solid R-tamsulosin-S-BPA salt; (c) filtering the second mixture to obtain the solid R-tamsulosin-S-BPA salt; (d) basifying the solid R-tamsulosin-S-BPA salt to provide a third mixture comprising R-tamsulosin free base; (e) isolating the solid R-tamsulosin free base from the third mixture by extraction with at least one organic solvent and then removing the at least one organic solvent; and optionally (f) converting the R-tamsulosin free base to a pharmaceutically acceptable salt; (g) recovering the S-tamsulosin or a salt thereof from a filtrate obtained in step (c) above; and (h) recovering the S-BPA chiral resolving agent used in the process from mother liquors obtained in steps (e) or (g).