4-Aminobenzoic Acid → 4-(4-Cyano-2-(2,6-difluorophenyl)oxazol-5-ylamino)benzoic acid

Participants

Reaction Conditions

Reaction Steps

A solution of tris(dibenzylideneacetone)dipalladium(0) (0.337 g, 0.368 mmol) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (0.213 g, 0.368 mmol) in n-butanol:dioxane (1:1) (5 mL) was stirred at room temperature for 3 minutes. Then 5-bromo-2-(2,6-difluorophenyl)oxazole-4-carbonitrile (1.50 g, 5.262 mmol), 4-aminobenzoic acid (2.165 g, 15.787 mmol) and cesium carbonate (3.429 g, 10.525 mmol) were added and the mixture heated in the microwave for 3 minutes at 140° C. The reaction was diluted with EtOAc and washed with water. The organic phase was passed through an MP-SH cartridge, dried over MgSO4 and the solvent removed in vacuo. The residue was purified by column chromatography using a 20-45% EtOAc:hexane gradient then further purified by trituration of the solid in DCM:hexane (1:1) to afford 4-(4-cyano-2-(2,6-difluorophenyl)oxazol-5-ylamino)benzoic acid (0.251 g, 0.735 mmol, 14%) as a light yellow solid. 1H NMR (DMSO) δ 7.34 (2H, t), 7.40 (2H, d), 7.66 (1H, m), 7.92 (2H, d), 11.16 (1H, br s), 12.76 (1H, br s). LCMS (3) Rt: 1.53 min; m/z (ES+) 342.

Provenance & Evidence