反应详情

Purge a mixture of methyl 5-cyano-2-(difluoromethyl)pyridine-3-carboxylate (160 g, 707.4 mmol) and EtOH (2 L) with nitrogen and stir 15 min. Add hydrochloric acid (37 wt % aqueous, 273 mL, 3183.2 mmol, 4.5 equiv) and palladium (5% on carbon, 48 g, 22.5 mmol, 0.031 equiv) in EtOH (100 mL), and stir the resulting suspension under 60 psi of hydrogen at room temperature for 70 min. Remove the solids by filtration over diatomaceous earth; wash the solid cake with EtOH (1 L); and concentrate the filtrate under reduced pressure. Repeat this procedure twice; combine the solids; and slurry in Et2O:DCM [10:1, 5.5 L]. Filter the solids and dry the resulting material at 45° C. for 3 hours to give the title compound as a light brown solid (714 g, 96% yield). MS (m/z) 216 (M+1).

1. customPurge
2. customRemove the solids
3. filtrationby filtration over diatomaceous earth
4. washwash the solid cake with EtOH (1 L)
5. concentrationand concentrate the filtrate under reduced pressure
6. filtrationFilter the solids
7. customdry the resulting material at 45° C. for 3 hours