3-Hydroxyanthranilic Acid → 2-Oxo-2,3-dihydro-1,3-benzoxazole-4-carboxylic acid

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Reaction Conditions

Reaction Steps

2-amino-3-hydroxybenzoic acid (1.2 g, 7.8 mmol) was suspended in 20 ml of THF and at 0° C. CDI (1.9 g, 1.5 equiv.) was added. The mixture was warmed at 80° C. for 5 hours. The solvent was evaporated and the crude was dissolved in AcOEt (30 ml) and washed with water (1×20 ml) and brine. The organic phase was dried over sodium sulfate and concentrated under vacuum. The purification of the crude residue by crystallization from EtOAc/ether gave 520 mg of an orange solid. Yield=37% 1HNMR (DMSO, 200 MHz) δ 7.45 (3H, m), 10.40 (1H, bs), 12.00 (1H, bs)

Provenance & Evidence