2-Amino-3-methylbenzoic acid → 8-methyl-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

Participants

Reaction Steps

To a solution of 2-amino-3-methylbenzoic acid (9.07 g, 60 mmol) in THF (60 mL) was added simultaneously diisopropylethylamine (20.9 mL) and a solution of triphosgene (5.94 g, 20 mmol) in dichloromethane (60 mL) over 30 minutes period. After the addition was completed, the mixture stirred at ambient temperature for 16 hours. Solid was filtered and washed with ether (2×100 mL) and H2O (3×50 mL), and dried in high vacuum to afford the title compound (10.02 g, 94% yield) as a white solid. 1H NMR (DMSO) δ 11.02 (s, 1H), 7.76 (d, 1H, J=7.7 Hz), 7.57 (d, 1H, J=7.5 Hz), 7.17–7.13 (m, 1H), 2.32 (s, 3H).

Provenance & Evidence