Bepotastine → Bepotastine Besilate

Participants

Reaction Steps

In 25 ml of ethyl acetate was dissolved 0.5 g (1.29 mmol) of (S)-4-[4-[(4-chlorophenyl)(2-pyridyl)methoxy]piperidino]butanoic acid obtained according to Example 1, and then, 0.20 g (1.14 mmol) of benzenesulfonic acid monohydrate was added and the mixture was concentrated under reduced pressure. To the residue was added again 25 ml of ethyl acetate and the mixture was allowed to stand for about one week, part of the syrupy product was crystallized. When the material was stirred by a spatula and further allowed to stand, whole parts were crystallized. This crystals were recrystallized from 5 ml of acetonitrile to afford 0.42 g (Yield: 67.3%, optical purity: 99.2% e.e.) of the desired product as pale gray prisms.

Provenance & Evidence