Trifluoroacetic acid → 9-bromo-8-chloro-4,6-dimethylbenzo[c][2,7]naphthyridin-5(6H)-one

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Reaction Conditions

Reaction Steps

To a solution of 8-chloro-4,6-dimethylbenzo[c][2,7]naphthyridin-5(6H)-one (0.2 g, 0.773 mmol) in acetonitrile (4 mL) at −30° C. was added trifluoroacetic acid (0.089 mL, 1.160 mmol) and 1-bromopyrrolidine-2,5-dione (0.151 g, 0.850 mmol). The mixture was heated to 80° C. overnight. The reaction mixture was concentrated, diluted with ethyl acetate and excess aqueous 10% NaHCO3. The ethyl acetate layer was concentrated. The residue was purified by prep. HPLC to afforded 9-bromo-8-chloro-4,6 dimethylbenzo[c][2,7]naphthyridin-5(6H)-one (120 mg, 0.351 mmol, 45% yield) as white solid. LC/MS (ESI) m/e 337.0 [(M+H)+, calcd for C14H11BrClN2O, 337.0]; LC/MS retention time (Method C): tR=2.55 min; 1H NMR (400 MHz, METHANOL-d4) ppm 3.11 (s, 3H), 3.75 (s, 3H), 7.81 (s, 1H), 8.20-8.26 (m, 1H), 8.68 (d, J=5.6 Hz, 1H), 8.79 (s, 1H).

Provenance & Evidence