反应详情

To a solution of 2-ethyl-imidazo[1,2-a]pyridine (2.17 g, 14.9 mmol) in ethanol (25 mL) was added bromine (2.0 g, 12.5 mmol) in water (5 mL) dropwise at rt. After stirring at rt for 4 h, ethanol was evaporated under reduced pressure. The residue was basified with aqueous sodium bicarbonate and extracted with methylene chloride (3×). The organic phase was washed with brine and dried over anhydrous magnesium sulfate. Concentration followed by flash chromatography eluting with 20% ethyl acetate in hexanes, followed by 50% ethyl acetate in hexanes afforded the title compound as a viscous oil. 1H NMR (500 MHz, CDCl3) δ 1.36 (t, J=7.5 Hz, 3H), 2.83 (q, J=7.6 Hz, 2H), 6.88 (t, J=6.8 Hz, 1H), 7.20 (m, 1H), 7.55 (dd, J=8.9, 0.9 Hz, 1H), 8.05 (dd, J=6.9, 1.2 Hz, 1H).

1. customethanol was evaporated under reduced pressure
2. extractionextracted with methylene chloride (3×)
3. washThe organic phase was washed with brine
4. dry with materialdried over anhydrous magnesium sulfate
5. concentrationConcentration
6. washeluting with 20% ethyl acetate in hexanes