C[O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[C:14](=[O:15])[N:13]3[CH:16]=[CH:17][S:18][C:12]3=[N:11][C:10]=2[CH3:19])=[CH:5][CH:4]=1.Br>C(O)(=O)C>[OH:2][C:3]1[CH:4]=[CH:5][C:6]([C:9]2[C:14](=[O:15])[N:13]3[CH:16]=[CH:17][S:18][C:12]3=[N:11][C:10]=2[CH3:19])=[CH:7][CH:8]=1Intermediate 9 (4.8 g, 17.726 mmol) was treated with HBr (35 ml) and acetic acid (35 ml) at room temperature and the reaction mixture was then heated to reflux overnight for 15.0 g. After completion of the reaction, the mixture was concentrated and basified with NaHCO3 and extracted with ethyl acetate. Combined organic layer was washed with water, brine, dried over anhydrous Na2SO4 purified using 5% CH3OH in chloroform to afford 3.0 g of the desired compound; 1H NMR (300 MHz, DMSO-d6) δ 2.17 (s, 3H), 6.76-6.79 (m, 2H), 7.05-7.08 (m, 2H), 7.48 (d, J=4.8 Hz, 1H), 7.96 (d, J=5.1 Hz, 1H), 9.47 (s, 1H); ESI-MS (m/z) 259.50 (M+H)+.
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