N-bromobutanimide → 3-bromo-2-(o-tolyl)-9H-benzo[f]imidazo[1,2-d]pyrido[2,3-b][1,4]diazepine

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Reaction Steps

To a solution of 2-(o-tolyl)-9H-benzo[f]imidazo[1,2-d]pyrido[2,3-b][1,4]diazepine (0.2 g, 1 eq.) in THF (5 mL) was added N-bromosuccinimide (0.11 g, 1 eq.). The reaction was stirred at room temperature for 15 minutes, poured onto water (30 mL) and extracted with ethyl acetate (2×30 mL). The organic extracts were combined, washed with saturated sodium bicarbonate (1×50 mL), water (1×50 mL), brine (1×50 mL) and dried over sodium sulfate. After filtration and concentration under reduced pressure, the crude product was purified by column chromatography (20% ethyl acetate in hexanes). The 3-bromo-2-(o-tolyl)-9H-benzo[f]imidazo[1,2-d]pyrido[2,3-b][1,4]diazepine (0.19 g, 77%) was obtained as an off-white solid. M.p.: 220-222° C.; 1H NMR (DMSO-d6) 400 MHz δ 8.64 (s, 1H), 8.27 (dd, JA=3.6 Hz, JB=1.6 Hz, 1H), 8.03 (dd, JA=7.2 Hz, JB=1.6 Hz, 1H), 7.78 (dd, JA=7.6 Hz, JB=1.2 Hz, 1H), 7.44 (d, J=6.8 Hz, 1H), 7.38-7.23 (m, 6H), 7.09 (t, J=7.6 Hz, 1H), 2.37 (s, 3H); LCMS: 403 [M+H].

Provenance & Evidence