Phosgene → (R,R)-3-[1-(3,4-dimethoxyphenyl)prop-2-yl]-5-(3-chlorophenyl)oxazolidin-2-one

Participants

Reaction Conditions

Reaction Steps

A solution of 5.0 g. of (R)-N-(3-methoxy-4-n-butoxybenzyl)-N-[2-(3-chlorophenyl)-2-hydroxyeth-1-yl]-1-(3,4-dimethoxyphenyl)-prop-2-ylamine (obtained in Example 2) in 45 mL of toluene is added to 406 mg. of sodium hydride at room temperature. The mixture is stirred for one hour, 1.29 mL of 2,6-lutidine are added, and stirring is continued for 30 minutes. The reaction mixture then is added with stirring to 5.74 mL of a 20% solution of phosgene in toluene which has been cooled to 0° C. Excess phosgene is destroyed with 3N sodium hydroxide and the reaction mixture diluted with toluene, washed sequentially with 3N sodium hydroxide and brine, dried over magnesium sulfate, and evaporated to yield (R,R)-3-[1-(3,4-dimethoxyphenyl)prop-2-yl]-5-(3-chlorophenyl)oxazolidin-2-one. This is further purified by stirring in heptane at 55° C. for 15 minutes, filtering, washing with additional heptane, and recrystallization from 5:4 ethyl acetate:heptane to yield white crystals. Gas chromatography indicates the chemical purity is 99.3% and HPLC indicates the de is 99.6%.

Provenance & Evidence