2-Aminophenol → 4-(1,3-Benzoxazol-2-yl)benzoic acid

Participants

Reaction Steps

Resin-bound 4-carboxybenzaldehyde (subn. 0.60 mmol/g, 400 mg, 0.24 mmol) was treated with a solution of 2-aminophenol (262 mg, 2.4 mmol) in DMA (3 mL). The suspension was shaken at room temperature for 24 h. Tetracyanoethylene (307 mg, 2.4 mmol) was added, and the mixture stirred at room temperature for an additional 24 h. The resin was filtered, washed with DMA and DCM, and dried under high vacuum. The benzoxazole was cleaved from the solid support with 20% (v/v) TFA in DCM (2×5 mL, 15 min) and the combined filtrates were evaporated to give the title compound. 1H NMR (CD3OD) δ 7.36-7.45 (m, 2H), 7.62-7,67 (m, 111), 7.72-7.77 (m, 1H), 8.17 (d, 2H, J=8.3 Hz), 8.29 (d, 2H, J=8.3 Hz). MS (API-ES+) m/z 240 (M+H).

Provenance & Evidence