2,2,2-Trifluoroethanol → 2,3-Dimethyl-4-(2,2,2-trifluoroethoxy)pyridine 1-oxide

Temperature

85.5 °C

13.5 ml of 2,2,2-trifluoroethanol were added to the solution of 2,3-dimethyl-4-nitropyridine N-oxide (60 ml, 0.080 mole) obtained in the previous step. Then methylene chloride was distilled off. The resulting concentrated solution was added to a solution of 14.85 g (0.133 mole) potassium tert-butoxide in 54 ml of 2,2,2-trifluoroethanol and 0.034 g of palladium(II) chloride. The reaction mixture was heated to 83-88° C. for 6-8 hours. After cooling to 30° C., potassium nitrite was filtered off, following by distillation of 2,2,2-trifluoroethanol. To this residue 17 ml of a saturated solution of sodium chloride were added and the pH was adjusted by the addition of conc. hydrochloric acid to 6.6. The product was extracted with methylene chloride and 100 ml of a saturated solution of sodium chloride. The organic phases were dried with sodium sulphate and concentrated to a volume of 40 ml. The yield was 95-97%, determined by HPLC.

1. customobtained in the previous step
2. distillationThen methylene chloride was distilled off
3. temperatureAfter cooling to 30° C.
4. filtrationpotassium nitrite was filtered off
5. distillationfollowing by distillation of 2,2,2-trifluoroethanol
6. additionTo this residue 17 ml of a saturated solution of sodium chloride were added
7. additionthe pH was adjusted by the addition of conc. hydrochloric acid to 6.6
8. extractionThe product was extracted with methylene chloride and 100 ml of a saturated solution of sodium chloride
9. dry with materialThe organic phases were dried with sodium sulphate
10. concentrationconcentrated to a volume of 40 ml

ORD record

ord-4ff2e4477eda449bb5f27d8c489dfcb1

Source dataset

uspto-grants-2010_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07662968B2