[NH2:1][CH2:2][CH:3]([C:5]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[C:7]([O:13][CH3:14])[CH:6]=1)[OH:4].[CH3:15][S:16]([CH3:18])=O.[OH-:19].[K+]>C(=S)=S>[CH3:14][O:13][C:7]1[CH:6]=[C:5]([CH:3]2[O:4][C:15](=[S:16])[NH:1][CH2:2]2)[CH:10]=[CH:9][C:8]=1[O:11][CH3:12].[CH3:14][O:13][C:7]1[CH:6]=[C:5]([CH:3]2[S:16][C:18](=[O:19])[NH:1][CH2:2]2)[CH:10]=[CH:9][C:8]=1[O:11][CH3:12]45 mmol of 2-amino-1-(3,4-dimethoxyphenyl)-ethanol is dissolved in 65 ml. of absolute dimethyl sulfoxide and combined in succession with 1.8 g. of pulverized potassium hydroxide and 1.4 ml. of carbon disulfide at 10°. The reaction mixture is then stirred under the exclusion of moisture for 2.5 hours. After withdrawing the dimethyl sulfoxide under vacuum, the residue is combined with 100 ml. of water and extracted three times with 100 ml. of chloroform. The combined chloroform phases are dried over anhydrous magnesium sulfate, filtered, and concentrated. The residue is chromatographed over 125 g. of silica gel with chloroform:methanol (96:4). After recrystallization of the corresponding fractions from methanol, a 9% yield of 5-(3,4-dimethoxyphenyl)-2-oxazolidinethione, m.p. 177°-178° is obtained in addition to a 6% yield of 5-(3,4-dimethoxyphenyl)-2-thiazolidinone, m.p. 167°-169°.
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