[NH2:1][C:2]1[C:10]([Br:11])=[CH:9][CH:8]=[CH:7][C:3]=1[C:4](O)=[O:5].[N:12]([CH3:15])=[C:13]=[S:14].CCN(CC)CC>CCO>[Br:11][C:10]1[CH:9]=[CH:8][CH:7]=[C:3]2[C:2]=1[NH:1][C:13](=[S:14])[N:12]([CH3:15])[C:4]2=[O:5]A solution of 2-amino-3-bromobenzoic acid (Maybridge, Trevillett, UK; 3.03 g, 14.02 mmol) and isothiocyanatomethane (Aldrich; 1.151 mL, 16.82 mmol) in EtOH (28 mL) was stirred at 75° C. for 3.5 d. Additional isothiocyanatomethane (2.302 mL, 33.64 mmol) and Et3N (2.74 mL, 19.63 mmol) were added, and the resulting mixture was stirred at 75° C. for 1 d. The mixture was concentrated in vacuo and the residue was triturated with Et2O (40 mL) to provide 8-bromo-3-methyl-2-thioxo-2,3-dihydroquinazolin-4(1H)-one (2.90 g, 10.70 mmol, 76% yield) as a yellow-orange solid: 1H NMR (400 MHz, CDCl3) δ ppm 9.52 (1H, br. s.), 8.11 (1H, d, J=8.0 Hz), 7.85 (1H, dd, J=7.9, 1.3 Hz), 7.20 (1H, t, J=7.9 Hz), 3.83 (3H, s). m/z (ESI, +ve) 271.0 (M+H)+.
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