Formaldehyde → 6-bromo-5-methyl-3-phenyl-2H-benzo[e][1,3]oxazin-4(3H)-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 3-bromo-6-hydroxy-2-methyl-N-phenylbenzamide (Intermediate 16-1, 40 mg, 0.131 mmol) and paraformaldehyde (11.77 mg, 0.392 mmol) in TFA (1 mL) was heated at 100° C. for 4 h. The TFA was removed under vacuum, and the residue was diluted with EtOAc (80 mL), washed with NaHCO3 (aq) (10 mL), water (10 mL) and brine (10 mL), and dried and concentrated. The residue was purified by column chromatogaphy (eluting with a gradient from 95:5 to 70:30 hexane-EtOAc) to give 6-bromo-5-methyl-3-phenyl-2H-benzo[e][1,3]oxazin-4(3H)-one (25 mg, 45%). 1H NMR (400 MHz, chloroform-d) δ 7.63 (1 H, d, J=8.80 Hz), 7.37-7.50 (3 H, m), 7.29-7.35 (2 H, m), 6.81 (1 H, d, J=8.80 Hz), 5.48 (2 H, s), 2.80 (3 H, s). Mass spectrum m/z 318, 320 (M+H)+.

Provenance & Evidence