反应详情

A mixture of 6-chloropyridine-3-carboxylic acid (6.0 g, 38.1 mmol), 2,2,2-trifluoroethanol (8.2 mL, 114.2 mmol) and potassium hydroxide (10.7 g, 190.4 mmol) in DMSO (50 mL) was stirred at 120 C for 18 h and left standing at room temperature for 2 days. A further 2 equivalents of potassium hydroxide and 1.5 equivalent of 2,2,2-trifluoroethanol were added and the reaction mixture was stirred at 120 C for 18 h. The mixture was acidified with a concentrated aqueous solution of HCl until a cream precipitate appeared. The precipitate was collected by filtration, washed with a 1N aqueous solution of HCl before being dissolved in EtOAc, washed 3 times with a 1N aqueous solution of HCl and 3 times with brine. The organic phase was dried over sodium sulfate, filtered and concentrated under vacuum to afford the title compound as a cream solid (6.9 g, 82%). Method C HPLC-MS: MH+ requires m/z=222 Found: m/z=222, Rt=1.24 min (98%).

1. waitleft
2. waitstanding at room temperature for 2 days
3. stirringthe reaction mixture was stirred at 120 C for 18 h
4. filtrationThe precipitate was collected by filtration
5. washwashed with a 1N aqueous solution of HCl
6. dissolutionbefore being dissolved in EtOAc
7. washwashed 3 times with a 1N aqueous solution of HCl and 3 times with brine
8. dry with materialThe organic phase was dried over sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated under vacuum