Water → Ondansetron

Participants

Reaction Steps

3-[(Dimethylamino)methyl]-1,2,3,9-tetrahydro-9-methyl-4H-carbazol-4-one hydrochloride (10 g, 34 mmol) and 2-methylimidazole (16.8 g, 205 mmol, 6.0 eq.) were suspended in mixture of water (75 ml) and dimethyl formamide (37.5 ml). The reaction mixture was heated to reflux (102–103° C.) and stirred for a further 6 hours at this temperature. The reaction mixture was cooled to 5–10° C. and stirred for half an hour at this temperature. The precipitated crude ondansetron base was filtered and washed with cold water (3×90 ml) and dried under vacuum at 60° C. to give ondansetron base (9.68 g, 96.4% yield) in 98.9% HPLC purity.

Provenance & Evidence