反应详情

温度

20 °C

A solution of 10.0 g of methyl (2R,3S)-3-t-butoxycarbonylamino-2-hydroxy-3-phenylpropionate, 0.334 g of pyridinium p-toluenesulphonate and 3.75 cm3 of trimethyl orthoformate in 70 cm3 of toluene is heated to reflux. 4 cm3 of solvent are distilled off. After cooling to a temperature in the region of 20° C. and filtration, the filtrate is concentrated to dryness under reduced pressure. The residue is taken up with 50 cm3 of hexane. The slurry obtained is filtered, rinsed and drained. 4.6 g of (4S,5R)-3-t-butoxycarbonyl-2-methoxy-4-phenyl-5-methoxycarbonyl-1,3-oxazolidine are thereby obtained in a 40% yield in the form of a mixture of diastereoisomers, the characteristics of which are as follows:

1. distillation4 cm3 of solvent are distilled off
2. concentrationthe filtrate is concentrated to dryness under reduced pressure
3. customThe slurry obtained
4. filtrationis filtered
5. washrinsed