Benzene → Esomeprazole

Participants

Reaction Steps

In a later publication in Tetrahedron Asymmetry 11 (2000), 1729-1732 the inventors of the above mentioned Chinese patent application reported the resolution of omeprazole using (S)-BINOL. An inclusion complex of (S)-BINOL and (S)-omeprazole was obtained as a grey-blue complex with 90.3% e.e. by mixing racemate omeprazole and (S)-(−)-BINOL in the mole ratio 1:1.5, in a solvent mixture of benzene:hexane (v/v=4:1) at 110° C. The inclusion complex obtained was further purified by recrystallization in benzene:hexane (v/v, 1:1) and separated on a silica gel column to yield (S)-(−)-omeprazole with 98.9% e.e. and 84.1% overall yield. The (S)-(−)-omeprazole so obtained was recrystallized in water to obtain as a white powder with 99.2% e.e.

Provenance & Evidence