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

Participants

Reaction Conditions

Reaction Steps

A solution of NaOH (6.6 g, 165 mmol) in water (300 mL) was treated with 2-amino-6-methoxylbenzoic acid (10 g, 59.9 mmol); cooled to 0° C., treated dropwise with a 20% wt solution of phosgene in toluene (75 mL), stirred overnight at room temperature and filtered. The filter cake provided 10.5 g of the desired product (yield: 91.0%). 1H NMR (DMSO-d6) δ 3.85 (s, 3H), 6.65 (d, 1H), 6.80 (d, 1H), 7.65 (t, 1H), 11.58 (br s, 1H); MS (ESI(−) m/e 192 (M−H)−.

Provenance & Evidence