Acetic Acid → Esomeprazole

Participants

Reaction Steps

To aqueous sodium hydroxide (2.03 ml, 1.5 M, 3.04 mmol) at ambient temperature was added omeprazole (1 g, 2.90 mmol) in 5 portions over 10 min. On complete dissolution, ethanol (35 ml) and (S)-1,1,2-triphenyl-1,2-ethanediol (1.26 g, 4.34 mmol) were added. To the resulting colourless solution at ambient temperature was added a solution of aqueous acetic acid (3.04 ml, 1 M, 3.04 mmol) dropwise over 1 h and, on complete addition, stirring was continued for 4 h. The solid was filtered, was washed with ethanol (3×15 ml) and was dried in vacuo to afford (S)-omeprazole.2[(S)-1,1,2-triphenyl-1,2-ethanediol] (925 mg, 69%, 96.4% ee) as a white powder.

Provenance & Evidence