Carbon Dioxide → 3-(4-(1-Benzyl-1,2,5,6-tetrahydropyrid-4-yl)-3,5-difluorophenyl)-5(R)-acetoxy-methyloxazolidin-2-one

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Reaction Steps

3-(4-(1-Benzyl-1,2,5,6-tetrahydropyrid-4-yl)-3,5-difluorophenyl)-5(R)-hydroxy-methyloxazolidin-2-one (20 g, 50 mM, see WO 97-30995) was suspended by stirring in dry dichloromethane (400 ml) under nitrogen at 0°, and treated with triethylamine (5.5 g, 54.4 mM) and 4-dimethylaminopyridine (0.3 g, 2.7 mM). Acetic anhydride (5.3 g, 52 mM) was added dropwise to give a solution, which was stirred for 1 hour, allowing the temperature to rise to ambient. The mixture was shaken with 5% aqueous sodium bicarbonate (200 ml) until carbon dioxide evolution ceased. The organic phase was separated, dried (magnesium sulfate) and evaporated, then azeotroped with toluene (2×50 ml) to give semi-crystalline product of sufficent purity for the next stage (24 g).

Provenance & Evidence