8-chloro-2-methyl-4H-benzo[d][1,3]oxazin-4-one → (2-Amino-3-chlorophenyl)(phenyl)methanone

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Reaction Steps

Phenylmagnesium bromide (3.11 mL, 3.0 M in ether, 9.34 mmol) was added at room temperature to a solution of 8-chloro-2-methyl-4H-3,1-benzoxazin-4-one (2.15 g, 10.9 mmol) in benzene (10 mL) and tetrahydrofuran (3 mL). The reaction was refluxed for 2h, cooled, and quenched with 2N hydrochloric acid (10 mL). The layers were separated and the organic phase washed with 5% sodium hydroxide, dried over magnesium sulfate, and concentrated. The residue was refluxed in ethanol (12 mL) and 6N hydrochloric acid (6 mL) overnight, then concentrated in vacuo. The residue was dissolved in benzene (30 mL) and treated with 5N ammonium hydroxide (20 mL). The organic extract was dried and concentrated. The crude product was purified by chromatography (silica gel, 0 to 5% ethyl acetate in hexane gradient elution), giving the title compound (0.84 g). 1H NMR (500 MHz, CDCl3) δ 7.63 (d, J=7 Hz, 2H), 7.54 (t, J=7 Hz, 1H), 7.49–7.42 (m, 3H), 7.39 (d, J=8 Hz, 1H), 6.56 (t, J=8 Hz, 1H), 6.58 (br s, 2H).

Provenance & Evidence