反应详情

A mixture of 1.62 g (10 mmol) of 2,2,3,3,3-pentafluoropropanimidamide and 2.22 g (10 mmol) of ethyl 2-(ethoxymethylene)-4,4-difluoro-3-oxobutanoate (for preparation see WO 2005/123690) in 10 ml of ethanol is stirred under reflux for 4 days after adding 0.68 g (10 mmol) of sodium ethylate. Concentration by evaporation in vacuo is then carried out and the residue is taken up in 10 ml of water and extracted twice with 10 ml of ethyl acetate. The organic phases are washed successively with 5 ml of water and 5 ml of saturated sodium chloride solution, dried over sodium sulphate, filtered and concentrated by evaporation in vacuo. Chromatographic purification with a mixture of cyclohexane and ethyl acetate gives 1.26 g of ethyl 4-(difluoromethyl)-2-(pentafluoroethyl)pyrimidine-5-carboxylate (40%) as a white solid.

1. temperatureunder reflux for 4 days
2. concentrationConcentration
3. customby evaporation in vacuo
4. extractionextracted twice with 10 ml of ethyl acetate
5. washThe organic phases are washed successively with 5 ml of water and 5 ml of saturated sodium chloride solution
6. dry with materialdried over sodium sulphate
7. filtrationfiltered
8. concentrationconcentrated by evaporation in vacuo
9. customChromatographic purification
10. additionwith a mixture of cyclohexane and ethyl acetate