[F:1][C:2]([F:16])([F:15])[C:3]1[CH:4]=[C:5]([NH:9][CH2:10][CH2:11][C:12]([OH:14])=O)[CH:6]=[CH:7][CH:8]=1.[NH2:17][C:18](N)=[O:19].O>C(O)(=O)C>[F:15][C:2]([F:1])([F:16])[C:3]1[CH:4]=[C:5]([N:9]2[CH2:10][CH2:11][C:12](=[O:14])[NH:17][C:18]2=[O:19])[CH:6]=[CH:7][CH:8]=1A solution of 3-(3-trifluoromethylphenylamino)propanoic acid (2.0 g) (prepared in Reference Example 95) and urea (1.0 g) in acetic acid (20.0 ml) was stirred with heating under reflux for seven hours. To the reaction mixture was water (50 ml) and the resulting mixture was extracted with ethyl acetate (30 ml×3). The organic layer was washed with water (20 ml×2) and saturated saline (20 ml), dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: chloroform/methanol) to afford 1-(3-trifluoromethylphenyl)dihydropyrimidin-2,4(1H,3H)-dione (1.5 g).
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