Phosphorus pentachloride → 4-chloro-2,2-dimethyl-2H-1,3-benzoxazine

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Reaction Steps

To a solution of 2,2-dimethyl-2H-benzo[e][1,3]oxazin-4(3H)-one (100 g, 0.56 mol) in POCl3 (500 mL) was added PCl5 (170 g, 0.84 mol) at the room temperature. The mixture was hearted at 60° C. overnight. The solvent was removed by distillation under atmospheric pressure and the residue was distilled under reduced pressure (85-86° C., 2.5 mmHg) to give 4-chloro-2,2-dimethyl-2H-benzo[e][1,3]oxazine (50 g, 45%). 1H NMR (400 MHz, CDCl3) δ 7.55 (dd, J=1.6, 8.4 Hz, 1H), 7.38 (dt, J=1.6, 8.0 Hz 1H), 6.95 (t, J=6.8 Hz 1H), 6.79 (d, J=8.0 Hz 1H), 1.61 (s, 6H).

Provenance & Evidence