反应详情

714 mg of 2-ethoxy-2-hydroxyacetic acid p-nitrobenzyl ester and 4 g of molecular sieve A4 are added to a solution of 245 mg of (3S,4R)-4-acetylthio-3-methoxy-2-oxoazetidine in a mixture of 8 ml of toluene and 2 ml of dimethylformamide and the mixture is stirred overnight at room temperature. The molecular sieves are filtered off from the mixture and the filtrate is concentrated by evaporation in vacuo. The residue is chromatographed over silica gel, and by elution with toluene/ethyl acetate (9:1 and 4:1) the title compound, contaminated with some glyoxylate, is obtained.

1. filtrationThe molecular sieves are filtered off from the mixture
2. concentrationthe filtrate is concentrated by evaporation in vacuo
3. customThe residue is chromatographed over silica gel
4. washby elution with toluene/ethyl acetate (9:1 and 4:1) the title compound
5. customis obtained