Methanesulfonic Acid → Paroxetine Impurity 10

Participants

Reaction Conditions

Reaction Steps

A round bottomed flask was charged with a solution of paroxetine base (23.5 g) in toluene (50 ml), obtained directly from the base hydrolysis of the N-phenoxycarbonyl intermediate. The toluene was removed in vacuo to produce an oily residue. To this residue was added propan-2-ol (50 ml) and the mixture was warmed to ensure total dissolution of the paroxetine. The temperature of the solution was cooled to 18° C. and methanesulfonic acid (6.86 g) was added, then the solvents were removed at reduced pressure and replaced with fresh propan-2-ol (110 ml). The solution was heated to reflux temperature, cooled to 18° C., and seeded with crystalline paroxetine methanesulfonate. Crystallisation was induced with vigorous stirring and insonation, and the product collected by filtration, and dried over phosphorus pentoxide in a vacuum desiccator to produce paroxetine methanesulfonate as a white crystalline solid.

Provenance & Evidence