Toluene → HCID 69002715, compound

Participants

Reaction Steps

A mixture of 2-(cyclopropanecarboxamido)-5-fluoro-3-hydroxybenzoate from Step D (180 mg, 0.71 mmol), p-toluenesulfonic acid monohydrate (202 mg, 1.07 mmol) and toluene (5 mL) was heated at reflux under nitrogen for 3 h. The reaction mixture was then cooled to room temperature, diluted with ethyl acetate, washed with a saturated solution of sodium bicarbonate and brine, dried over sodium sulfate, filtered and concentrated. The crude material was purified by Combi-flash chromatography (silica gel, 60:40 hexanes/ethyl acetate) to afford methyl 2-cyclopropyl-6-fluorobenzoxazole-4-carboxylate (115 mg, 69%) as a white solid: 1H NMR (300 MHz, CDCl3) δ 7.68 (dd, J=10.2, 2.4 Hz, 1H), 7.34 (dd, J=7.5, 2.4 Hz, 1H), 4.02 (s, 3H), 2.39-2.29 (m, 1H), 1.35-1.29 (m, 2H), 1.26-1.17 (m, 2H); 19F NMR (282 MHz, CDCl3) δ −116.29; MS (ESI+) m/z 236 (M+H).

Provenance & Evidence