反应详情

To a solution of ethyl 3-methyl-4-hydroxy-5-tert-butylbenzofuran-2-carboxylate, compound 12a (1.00 g, 3.62 mmol) and benzoyl chloride (0.763 g, 5.43 mmol) in 1,2-dichloroethane (40 mL) at 0° C. was added aluminum chloride (0.720 g, 5.43 mmol) and the resulting mixture warmed to reflux for 3.5 hours. The reaction was allowed to cool, poured into 2N HCl (100 mL) and extracted with methylene chloride (4×25 mL). The combined extracts were washed with 5% NaHCO3 (25 mL), dried (Na2SO4), and concentrated. Flash chromatography using 25% ethyl acetate in hexane as eluant afforded ethyl 3-methyl-4-hydroxy-5-tert-butyl-7-benzoylbenzofuran-2-carboxylate, compound 15 as an oil sufficiently pure for further chemistry. 1H NMR d 1.34 (3H, t, J=6 Hz), 1.51 (9H, s), 2.89 (3H, s), 4.35 (2H, q, J=6 Hz), 7.56 (3H, m), 7.86 (3H, m).

1. temperaturethe resulting mixture warmed
2. temperatureto reflux for 3.5 hours
3. temperatureto cool
4. extractionextracted with methylene chloride (4×25 mL)
5. washThe combined extracts were washed with 5% NaHCO3 (25 mL)
6. dry with materialdried (Na2SO4)
7. concentrationconcentrated