196404-55-4

1531632-32-2

196404-55-4

The (4S,5R)-3-(tert-butoxycarbonyl)-2-(4-methoxyphenyl)-4-phenyloxazolidine-5-carboxylic acid precursor obtained in the previous step (4.83 g, 9.88 mmol) was dissolved in 10 mL of methanol and 1.0 g of palladium hydroxide was added as a catalyst. Hydrogen was introduced into the reaction system at room temperature (pressure maintained at 20 psi) and the reaction was carried out for 1 h, during which the progress of the reaction was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the reaction mixture was filtered to remove the catalyst, and the filtrate was concentrated under reduced pressure and purified by column chromatography (eluent ratio of petroleum ether/ethyl acetate = 5:1) to afford (4S,5R)-3-(tert-butoxycarbonyl)-2-(4-methoxyphenyl)-4-phenyl-oxazolidine-5-carboxylic acid as a white solid (2.68 g, 67.9% yield).