Dimethylformamide → 3-(4,4-dimethyl-2-oxo-2,4-dihydro-1H-benzo[d][1,3]oxazin-6-yl)-5-fluorobenzonitrile

Participants

Reaction Conditions

Reaction Steps

A mixture of 6-(3-bromo-5-fluorophenyl)-4,4-dimethyl-2H-benzo[d][1,3]oxazin-2-one (1 g, 2.8 mmol), zinc cyanide (0.2 g, 1.7 mmol), and tetrakis(triphenylphosphine)-palladium (0) (0.2 g, 0.17 mmol) in dry DMF (20 mL) was degassed to remove oxygen and then was heated at 85° C. under a blanket of nitrogen for 6.5 hours. The reaction solution was cooled to room temperature and poured onto a cold saturated aqueous ammonium chloride solution (100 mL). The white precipitate appeared and was collected on a filter. The white solid was washed with the distilled water (3×20 mL) and dissolved in a mixture of ethyl acetate (10 mL) and methanol (10 mL). The solution was applied on a pad of silica gel and eluted with a mixture of ethyl acetate and hexane (1:1). After evaporation, 3-(4,4-dimethyl-2-oxo-1,4-dihydro-2H-benzo[d][1,3]oxazin-6-yl)-5-fluorobenzonitrile was obtained as a white solid (0.7 g, 84%): mp 253-254° C.; 1H-NMR (DMSO-d6) δ 10.4 (s, 1H, D2O exchangeable), 8.13 (s, 1H), 7.92 (m, 1H), 7.82 (m, 1H), 7.73 (m, 2H), 6.98 (d, 1H, J=8.2 Hz), 1.68 (s, 6H), 19F-NMR (DMSO-d6) δ −112.25 (m, 1F); MS (EI) m/z 296 (M+, 65%), Anal. Calc. For C17H13FN2O2: C, 68.91; H, 4.42; N, 9.45. Found: C, 68.85; H, 4.58; N, 9.14.

Provenance & Evidence