Hydrochloric Acid → Duloxetine Hydrochloride

Participants

Reaction Steps

According to prior art methods, duloxetine free base is treated with hydrochloric acid in the presence of ester or ketone solvents. The prior art methods employ hydrochloric acid in concentrated form, in diluted forms with ethyl acetate, or as a gas. The solid obtained is isolated by concentration and/or filtration, which is subsequently washed and dried to obtain duloxetine hydrochloride. Washing is generally carried out to remove the soluble by-products and drying is finally carried out to remove the residual solvents. The present inventors have observed that even after usual washing and drying steps, the finally obtained duloxetine hydrochloride is contaminated with 4-[3-(methylamino)-1-thiophen-2-ylpropyl]naphthalen-1-ol of Formula II in undesirable amounts.

Provenance & Evidence