反应详情

温度

100 °C

(6-Chloro-2-cyano-4-methyl-pyridin-3-yl)-carbamic acid tert-butyl ester (3.72 g) was dissolved in concentrated sulfuric acid (19 mL) and stirred for 1 h at 100° C. The reaction mixture was cooled to room temperature and water (19 mL) was slowly added. The reaction mixture was warmed again to 100° C. and stirred at this temperature for 2 h. Water was added after cooling to room temperature, the mixture was cooled in an ice bath and the pH was adjusted to ˜14 by slow addition of solid sodium hydroxide. The aqueous solution was washed 2× with MTB-ether, the aqueous layer was then adjusted to pH ˜2 by addition of 5 M hydrochloric acid and extracted 3× with ethyl acetate. The combined organic layer was washed with brine, dried over magnesium sulfate and concentrated in vacuum to afford 2.25 g of the title compound of the formula

1. temperatureThe reaction mixture was cooled to room temperature
2. temperatureThe reaction mixture was warmed again to 100° C.
3. stirringstirred at this temperature for 2 h
4. temperatureafter cooling to room temperature
5. temperaturethe mixture was cooled in an ice bath
6. washThe aqueous solution was washed 2× with MTB-ether
7. additionthe aqueous layer was then adjusted to pH ˜2 by addition of 5 M hydrochloric acid
8. extractionextracted 3× with ethyl acetate
9. washThe combined organic layer was washed with brine
10. dry with materialdried over magnesium sulfate
11. concentrationconcentrated in vacuum