Citric Acid → Sildenafil Citrate

Participants

Reaction Steps

In a 3-necked flask sildenafil (5 g, 10 mmol) was dissolved in acetone (40 ml) at 50° C. In a separate container, citric acid (2 g, 10 mmol) was dissolved in acetone (15 ml). Both solutions were filtered. The citric acid solution was added dropwise to the sildenafil solution and a white precipitate appeared immediately. Thereafter, the reaction mixture was heated and maintained at the solvent reflux temperature for 1 hour and subsequently allowed to cool over 3 hours to room temperature. The precipitate was collected by filtration and dried at 50° C. under 10 mm Hg to give sildenafil citrate in 95.5% yield.

Provenance & Evidence