反应详情

To a solution of 1,7-dimethylindole (2.85 g, 19.6 mmol) and TMEDA (3.3 mL, 21.6 mmol) in diethyl ether (30 mL) at −30° C. under N2 was added n-butyllithium (13.5 mL of a 1.6 M solution in hexanes, 21.6 mmol) dropwise. The resulting orange solution was heated to reflux for 1 h and then DMF (4.6 mL, 58.8 mmol) was added in one portion. The solution was stirred at room temperature overnight. Saturated aqueous NH4Cl solution was added and the mixture was then extracted with ethyl acetate (3×150 mL). The combined organics were washed with water (100 mL) and brine (100 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to provide an orange oil. Purification by flash column chromatography (silica gel, hexanes/ethyl acetate, 95:5) gave the title compound (1.57 g, 46%) as a yellow solid: 1H NMR (300 MHz, CDCl3) δ 9.83 (s, 1H), 7.54 (d, J=7.8 Hz, 1H), 7.21 (s, 1H), 7.09-7.02 (m, 2H), 4.39 (s, 3H), 2.79 (s, 3H).

1. temperatureThe resulting orange solution was heated
2. temperatureto reflux for 1 h
3. extractionthe mixture was then extracted with ethyl acetate (3×150 mL)
4. washThe combined organics were washed with water (100 mL) and brine (100 mL)
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customto provide an orange oil
9. customPurification by flash column chromatography (silica gel, hexanes/ethyl acetate, 95:5)