反应详情

The solution of 2.0 g (11.5 mmol) 3-chloro-2-hydroxypyridine-5-carboxylic acid in 28 mL (35 mmol) hydrochloric acid (1.25M in methanol) was stirred for 5 h under reflux. The reaction was allowed to cool to room temperature, poured on 100 mL 10% aqueous sodium bicarbonate solution and 100 mL ethyl acetate, extracted and washed with 100 mL brine. The aqueous layer was extracted a second time with 100 mL ethyl acetate and the combined organic layers dried with magnesium sulfate, filtered and concentrated under vacuum. The light yellow residue was suspended in 30 mL tert-butyl methyl ether, stirred for 1 h at room temperature and filtered to give the desired compound as a white solid (55%) which was pure enough for the next step. MS (Turbo Spray): m/z=188.1 [M+H].

1. temperatureunder reflux
2. extractionextracted
3. washwashed with 100 mL brine
4. extractionThe aqueous layer was extracted a second time with 100 mL ethyl acetate
5. dry with materialthe combined organic layers dried with magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated under vacuum
8. filtrationfiltered