反应详情

温度

90 °C

To a solution of 2,6-dimethylphenol (503 mg, 4.12 mmol), triphenylphosphine (1.08 g, 4.12 mmol) and ethyl 5-cyclobutyl-3-(hydroxymethyl)-4-isoxazolecarboxylate (929 mg, 4.12 mmol, from multiple batches) in toluene (10 mL) was added diisopropyl azodicarboxylate (0.741 mL, 4.12 mmol) dropwise. The solution was heated in a microwave reactor to 90° C. for 10 minutes. The solution was then concentrated and the residue was purified by chromatography (silica gel, 2.5% acetone in hexanes) to afford ethyl 5-cyclobutyl-3-{[(2,6-dimethylphenyl)oxy]methyl}-4-isoxazolecarboxylate (1.11 g, 81%). 1H-NMR (400 MHz, DMSO-d6) δ 7.01-6.90 (m, 3H), 5.02 (s, 2H), 4.20 (q, J=7 Hz, 2H), 4.20-4.10 (m, 1H), 2.37-2.30 (m, 4H), 2.14 (s, 6H), 2.11-2.01 (m, 1H), 1.95-1.85 (m, 1H), 1.22 (t, J=7 Hz, 3H).

1. concentrationThe solution was then concentrated
2. customthe residue was purified by chromatography (silica gel, 2.5% acetone in hexanes)