Sodium Hydroxide → (3S,4S)-1-(p-methoxybenzyl)-3-[(1R)-1-allyloxycarbonyloxyethyl]-4-tert.-butoxycarbonyl-2-azetidinone

Participants

Reaction Steps

At 0°, 24 ml of 1N NaOH, 820 mg of tetrabutylammonium bisulphate and 1 ml of chloroformic acid allyl ester are added to a solution of 2 g of (3S,4S)-1-(p-methoxybenzyl)-3-[(1R)-1-hydroxyethyl)-4-tert.-butoxycarbonyl-2-azetidinone in 24 ml of methylene chloride and the whole is stirred vigorously. After a reaction time of 20 and 40 minutes, further portions (each of 1 ml) of chloroformic acid allyl ester are added. The reaction mixture is diluted with methylene chloride, the aqueous phase is separated off and the organic layer is washed in succession with 5% aqueous citric acid and 8% aqueous NaHCO3 solution and then dried and concentrated by evaporation. After purifying by chromatography, the pure, amorphous title compound is obtained.

Provenance & Evidence