N-bromobutanimide → 1-(1-bromo-8,9-dihydro-3H-pyrazolo[3,4-c][2,7]naphthyridin-7(6H)-yl)-2-chloro-2-phenylethanone

Participants

Reaction Steps

To a solution of 2-chloro-1-(8,9-dihydro-3H-pyrazolo[3,4-c][2,7]naphthyridin-7(6H)-yl)-2-phenylethanone (0.340 g, 1.04 mmol) in dichloromethane (20 mL) was added N-bromosuccinimide (NBS, 0.195 g, 1.09 mmol). The reaction mixture was stirred for 16 hours at room temperature. During the reaction a yellow solid crashed out. The reaction was quenched by addition of aqueous NaHCO3. The aqueous layer was extracted with EtOAc (2×200 mL). The combined organic layer was dried (Na2SO4), filtered and concentrated under reduced pressure to give crude 1-(1-bromo-8,9-dihydro-3H-pyrazolo[3,4-c][2,7]naphthyridin-7(6H)-yl)-2-chloro-2-phenylethanone as a pale yellow solid (0.38 g, 90%). 1H NMR (400 MHz, DMSO-d6) δ11.08 (brs, 1H), 8.43 (s, 1H), 7.52-7.39 (m, 5H), 6.52 (s, 1H), 4.80 (m, 2H), 3.85 (m, 2H), 3.28 (m, 2H); LCMS [M+H]: 405. The product was used in the next step without any further purification.

Provenance & Evidence