Succinic Acid → Succinic Acid

Participants

Reaction Steps

Crude oily solifenacin (35 g) obtained in Example 1 is dissolved in isopropanol (100 mL) at room temperature (20-24° C.). In a separate flask the solution of succinic acid (11.30 g, 95.55 mmol) in isopropanol (130 mL) is prepared at reflux for 5 min. The hot succinic acid solution is slowly added to the solifenacin solution in isopropanol. The resulting mixture is left to reach room temperature. At ca. 45° C. the mixture turned to be cloudy and white crystalline solid begins to precipitate. The solution is left at room temperature for 2 h 30 min. The crystalline solid is filtered off and washed with cold isopropanol (10° C.) (3×40 mL), then it is dried under reduced pressure (0.1-0.15 mmHg, room temperature, 2 h) to dry mass. After two steps solifenacin succinate is obtained in 38.9 g, (84.8%) yield, of purity (HPLC) 99.39%. The final product (38 g) is recrystallized in isopropanol (150 mL), yielding 34.4 g (90.7%) of solifenacin succinate of purity (HPLC) 99.71%; T(onset)≈150° C.

Provenance & Evidence