Phosgene → 5-Methoxy-2H-3,1-benzoxazine-2,4(1H)-dione

Participants

Reaction Steps

A solution of 2-amino-6-methoxybenzoic acid (10 g, 60 mmol), water (330 mL), and sodium hydroxide (7.2 g, 176 mmol) was treated with phosgene (20% solution in toluene, 82 mL, 164 mmol) over 1 hour and filtered. The filter cake was dried to provide the desired product. MS (ESI(+)) m/e 194 (M+H)+, 211 (M+NH4)+, 216 (M+Na)+; (ESI(−)) m/e 192 (M−H)+; 1H NMR (300 MHz, DMSO-d6) δ 11.57 (s, 1H), 7.64 (t, 1H), 6.84 (d, 1H), 6.68 (d, 1H), 3.88 (s, 3H).

Provenance & Evidence