B(Br)(Br)Br.C[O:6][C:7]1[CH:8]=[C:9]2[C:13](=[CH:14][CH:15]=1)[C:12](=[O:16])[NH:11][C:10]2([CH3:18])[CH3:17].O>C(Cl)Cl>[OH:6][C:7]1[CH:8]=[C:9]2[C:13](=[CH:14][CH:15]=1)[C:12](=[O:16])[NH:11][C:10]2([CH3:18])[CH3:17]A 1 M solution of BBr3 in CH2Cl2 (88.0 mL, 88.0 mmol) is dissolved in dry CH2Cl2 under N2. A solution of lactam 57 (7.65 g, 40.0 mmol) in CH2Cl2 (50 mL) is added to the BBr3 solution dropwise over 10 min. The resulting mixture is stirred at rt overnight. The reaction mixture is poured into water and extracted with EtOAc (3×). The organic phase is dried (MgSO4), filtered, and evaporated, leaving the product 62 as a white solid (4.03 g, 57%), mp 231-233° C., which requires no purification. 1H NMR (DMSO-d6, 2.50 ppm) 8.18 (s, 1), 7.28 (d, 1, J=8.5), 6.75 (d, 1, J=1.6), 6.67 (dd, 1, J=8.5, 1.6), 1.25 (s, 6); 13C NMR (CDCl3 +DMSO-d6) 169.30, 161.06, 155.40, 124.68, 121.53, 115.39, 107.26, 57.98, 27.47; MS (MW=177.2, EI, eE=70 eV) m/z 177 (M+), 163, 162 (base peak).
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