[NH2:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH:13]=[CH:12][CH:11]=[C:10]([F:14])[CH:9]=2)=[CH:4][C:3]=1[CH:15]([OH:17])[CH3:16].Cl[C:19](Cl)([O:21]C(=O)OC(Cl)(Cl)Cl)Cl.C(=O)(O)[O-].[Na+].C(OCC)(=O)C>C1COCC1>[F:14][C:10]1[CH:9]=[C:8]([C:5]2[CH:6]=[CH:7][C:2]3[NH:1][C:19](=[O:21])[O:17][CH:15]([CH3:16])[C:3]=3[CH:4]=2)[CH:13]=[CH:12][CH:11]=1
A mixture of the above alcohol (0.2 g, 0.87 mmol) and triphosgene in anhydrous THF (20 mL) was stirred at room temperature under nitrogen. After 15 minutes, the mixture was treated with a saturated aqueous sodium bicarbonate solution (30 mL) and ethyl acetate (40 mL). The organic layer was separated, dried (MgSO4), and evaporated to give 6-(3-fluorophenyl)-4-methyl-1,4-dihydro-2H-3,1-benzoxazin-2-one as a white solid (0.18 g, 81%): mp 160-161° C.; 1H-NMR (DMSO-d6) δ 10.31 (s, 1H), 7.62 (dd, 1H, J=8.2, 1.9 Hz), 7.57 (s, 1H), 7.44-7.53 (m, 3H), 7.13-7.20 (m 1H), 6.97 (d, 1H, J=8.2 Hz), 5.57 (q, 1H, J=6.6 Hz), 1.63 (d, 3H, J=6.6 Hz). MS (ESI) m/z 256 [M−H]−.
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