反应详情

To a solution of ethyl-3-methyl-4-hydroxy-5-tert-butyl-benzofuran-2-carboxylate 12a (0.760 g, 2.75 mmol) in 30 mL dry (4A sieves) 1,2-dichloroethane at 5° C. under nitrogen was added a solution of thiophene-2-carbonyl-chloride (806 mg, 5.49 mmol) in 5 mL 1,2-dichloroethane followed by the portionwise addition of AlCl3 (0.733 g, 5.59 mmol). The cooling bath was removed and the reaction mixture allowed to warm to room temperature and then refluxed for 1.5 hours. The reaction mixture was then cooled and poured into 100 mL ice cold 2N HCl. The organic layer was removed and the aqueous layer extracted with methylene chloride (3×30 mL). The combined organic layers were washed with 5% NaHCO3 (50 mL), water (50 mL) and saturated NaCl (50 mL) and dried over Na2SO4. Concentration followed by flash chromatography (30% EtOAc in hexane) afforded compound 13 as an oil sufficiently pure for further use; 1H NMR d 1.41 (3H, t, J=6 Hz), 1.55 (9H, s), 2.90 (3H, s), 4.42 (2H, q, J=6 Hz), 7.19 (1H, dd, J=4 Hz), 7.75 (2H, d, J=4 Hz), 7.90 (1H, s).

1. customThe cooling bath was removed
2. temperaturerefluxed for 1.5 hours
3. temperatureThe reaction mixture was then cooled
4. additionpoured into 100 mL ice cold 2N HCl
5. customThe organic layer was removed
6. extractionthe aqueous layer extracted with methylene chloride (3×30 mL)
7. washThe combined organic layers were washed with 5% NaHCO3 (50 mL), water (50 mL) and saturated NaCl (50 mL)
8. dry with materialdried over Na2SO4
9. concentrationConcentration