反应详情

温度

26 °C

To an ice-cooled solution of 3-(trifluoromethyl)pyridin-2-ol (4 g, 24.53 mmol) in H2SO4 (26.1 mL, 491 mmol) was added nitric acid (1.206 mL, 27.0 mmol) dropwise. After 30 min, the ice bath was removed and the reaction was stirred at 26° C. for 10 h. The reaction mixture was added to 120 g ice. The resulting precipitate was collected by filtration, rinsed with additional H2O and air-dried to afford the first batch of product. Another crop of product was obtained after evaporating the mother liquor to less than 100 mL, cooling on an ice bath, and adding NaOH to adjust to pH=8. The mixture was extracted by EA (100 mL). The organic layer was dried and concentrated to give the product, which was combined with the first batch to yield a yellow solid of 5-nitro-3-(trifluoromethyl)pyridin-2-ol (2.63 g, 12.64 mmol, 51.5% yield): 1H NMR (400 MHz, CD3OD) δ: 8.86 (d, J=3.1 Hz, 1H), 8.55 (d, J=2.6 Hz, 1H); ES-LCMS m/z 209.0 (M+H).

1. customthe ice bath was removed
2. additionThe reaction mixture was added to 120 g ice
3. filtrationThe resulting precipitate was collected by filtration
4. washrinsed with additional H2O
5. customair-dried
6. customto afford the first batch of product
7. customAnother crop of product was obtained
8. customafter evaporating the mother liquor to less than 100 mL
9. temperaturecooling on an ice bath
10. additionadding NaOH
11. extractionThe mixture was extracted by EA (100 mL)
12. customThe organic layer was dried
13. concentrationconcentrated
14. customto give the product, which