[CH3:1][C:2]1([CH3:24])[NH:7][C:6](=[O:8])[C:5]2[S:9][C:10]([N:12]3[C:17]4[CH:18]=[CH:19][C:20]([O:22][CH3:23])=[CH:21][C:16]=4[O:15][CH2:14][CH2:13]3)=[N:11][C:4]=2[CH2:3]1.[Br:25]N1C(=O)CCC1=O>CC#N.C1COCC1>[Br:25][C:19]1[C:20]([O:22][CH3:23])=[CH:21][C:16]2[O:15][CH2:14][CH2:13][N:12]([C:10]3[S:9][C:5]4[C:6](=[O:8])[NH:7][C:2]([CH3:24])([CH3:1])[CH2:3][C:4]=4[N:11]=3)[C:17]=2[CH:18]=1To a stirred solution of Example 489 (0.05 g, 0.145 mmol) in MeCN (1 mL) and THF (1 mL) was added N-bromosuccinimide (0.026 g, 0.145 mmol). The mixture was stirred at r.t. overnight and then concentrated in vacuo. EtOAc (10 mL) and 1% aqueous sodium sulfite (5 mL) were added and the mixture was rapidly stirred for 10 minutes. The aqueous layer was extracted with EtOAc (10 mL) and then DCM (2×10 mL). The EtOAc extracts were concentrated in vacuo and the residue was dissolved in DCM (5 mL). The combined organic fractions were washed with brine (10 mL), dried (MgSO4), filtered and the solvent was evaporated in vacuo to give the title compound (0.062 g, 100%) as a light brown solid. δH (CDCl3) 8.17 (1H, s), 6.52 (1H, s), 5.22 (1H, s), 4.35-4.30 (2H, m), 4.10-4.05 (2H, m), 3.86 (3H, s), 2.88 (2H, s), 1.39 (6H, s). LCMS (ES+) 424.1, 426.0 (M+H)+, RT 3.47 minutes (Method 1).
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