[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:11]2[O:15][C:14](=[O:16])[NH:13][CH2:12]2)[CH:6]=[CH:7][C:8]=1[O:9][CH3:10].[H-].[Na+].[CH3:19]I>CN(C)C=O>[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:11]2[O:15][C:14](=[O:16])[N:13]([CH3:19])[CH2:12]2)[CH:6]=[CH:7][C:8]=1[O:9][CH3:10]10 mmol of 5-(3,4-dimethoxyphenyl)-2oxazolidinone is dissolved in 20 ml. of absolute dimethylformamide and combined with 11 mmol of sodium hydride. The mixture is then stirred for 40 minutes at 40°. After cooling, 20 mmol of methyl iodide in 5 ml. of dimethylformamide is added dropwise and thereafter the reaction mixture is agitated for 6 hours at 50°. After the dimethylformamide has been removed by evaporation, the mixture is taken up in chloroform and then washed first with a small amount of water and then with saturated sodium chloride solution, dried, filtered, and concentrated. The residue is chromatographed over 60 g. of silica gel with chloroform/methanol (96:4) as the eluent. Recrystallization from ethanol produces a 60% yield of 5-(3,4-dimethoxyphenyl)-3-methyl-2-oxazolidinone, m.p. 132°-133°.
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