反应详情

A stirred solution of methyl 5-bromo-6-methoxypyridine-2-carboximidoate (C29) (9.42 g, 38.4 mmol) in methanol (66 mL) and concentrated hydrochloric acid (6.6 mL) was heated under reflux for 18 hours. The reaction was concentrated to dryness under reduced pressure. The resulting solid was dissolved in dichloromethane (500 mL) and washed with saturated aqueous sodium bicarbonate solution (250 mL). The aqueous phase was extracted with dichloromethane (200 mL), and the combined organics were washed with water (250 mL), with saturated aqueous sodium chloride solution (250 mL), dried over magnesium sulfate and concentrated under reduced pressure to provide the title compound. The reaction was repeated on additional material (1.65 g, 6.73 mmol), worked up in a similar manner, combined with the first reaction, and purified by silica gel chromatography (Eluant: 10% ethyl acetate in heptane) to provide the title compound as a yellow solid. Yield: 4.48 g, 18.2 mmol, 40%. LCMS m/z 246.1 (M+1). 1H NMR (400 MHz, CDCl3) δ 3.97 (s, 3H), 4.11 (s, 3H), 7.59 (d, J=7.8 Hz, 1H), 7.93 (d, J=7.8 Hz, 1H).

1. temperatureunder reflux for 18 hours
2. concentrationThe reaction was concentrated to dryness under reduced pressure
3. dissolutionThe resulting solid was dissolved in dichloromethane (500 mL)
4. washwashed with saturated aqueous sodium bicarbonate solution (250 mL)
5. extractionThe aqueous phase was extracted with dichloromethane (200 mL)
6. washthe combined organics were washed with water (250 mL), with saturated aqueous sodium chloride solution (250 mL)
7. dry with materialdried over magnesium sulfate
8. concentrationconcentrated under reduced pressure