C(NC(C)C)(C)C.[Li]CCCC.[NH2:13][C:14]1[C:26]([Br:27])=[CH:25][C:17]2[C:18]([C:21]([NH:23][CH3:24])=[O:22])=[CH:19][O:20][C:16]=2[CH:15]=1.C([N-]C(C)C)(C)C.[Li+].CON(C)[C:39](=[O:41])[CH3:40]>C1COCC1>[C:39]([C:19]1[O:20][C:16]2[CH:15]=[C:14]([NH2:13])[C:26]([Br:27])=[CH:25][C:17]=2[C:18]=1[C:21]([NH:23][CH3:24])=[O:22])(=[O:41])[CH3:40]To a solution of diisopropylamine (3.76 g, 37.1 mmol) in THF (25 mL) was slowly added a solution of n-BuLi (2.5 mol/L in hexane) (16.5 mL, 40.5 mmol) under N2 at −78° C. and the resulting solution was stirred at −78° C. for 30 minutes. A solution of compound 6-amino-5-bromo-N-methylbenzofuran-3-carboxamide (2 g, 7.43 mmol) in THF (50 mL) was slowly added to the fresh lithium diisopropylamide at −78° C. and stirred for another one hour. To the resulting mixture was added N-methoxy-N-methylacetamide (3.83 g, 37.16 mmol) at −78° C. and stirred for another one hour. The reaction was quenched with saturated NH4Cl at −78° C. and the mixture was slowly warmed to room temperature. Water was added and the mixture extracted with EtOAc. The organic layers were washed with brine, dried over Na2SO4 and concentrated in vacuo to give the crude product. The crude product was purified by column chromatography to give compound 2-acetyl-6-amino-5-bromo-N-methylbenzofuran-3-carboxamide (700 mg, yield: 30%). 1H-NMR (CDCl3, 400 MHz) δ 10.00 (s, 1H), 8.76 (s, 1H), 6.86 (s, 1H), 4.54 (s, 2H), 3.00 (d, J=4.8 Hz, 3H), 2.70 (s, 3H). MS (M+H)+: 311/313.
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