Citric Acid → Sildenafil Citrate

Participants

Reaction Steps

In a 3-necked flask, sildenafil (5 g, 10 mmol) was dissolved in acetone (100 ml) at reflux. Citric acid (2 g, 10 mmol) was added, and a white precipitate appeared immediately. The reaction mixture was maintained at the reflux temperature for 1 hour and allowed to cool over 3 hours to room temperature. The precipitate was collected, filtered, and dried at 50° C. under 10 mm Hg to give pure sildenafil citrate in 94% yield.

Provenance & Evidence