反应详情

70.4 g (0.41 mol) of 2,6-difluorophenylacetic acid, 700 ml of ethanol and 35 ml of concentrated sulphuric acid are heated under reflux for 3 hours. The reaction mixture is then concentrated by evaporation, taken up in dichloromethane and the solution is extracted by shaking in succession with water, 2N sodium carbonate solution and again with water. After drying over magnesium sulphate, the organic phase is concentrated by evaporation. The residue is dissolved in 560 ml of ethanol. After the addition of 30 ml (31 g; 0.62 mol) of hydrazine hydrate, the whole is heated under reflux for 4 days. After cooling, the resulting crystals are filtered off to yield 56.4 g (74% of the theoretical yield) of 2,6-difluorophenylacetic acid hydrazide which melts at 177-178°.

1. temperatureunder reflux for 3 hours
2. concentrationThe reaction mixture is then concentrated by evaporation
3. extractionthe solution is extracted
4. dry with materialAfter drying over magnesium sulphate
5. concentrationthe organic phase is concentrated by evaporation
6. dissolutionThe residue is dissolved in 560 ml of ethanol
7. temperaturethe whole is heated
8. temperatureunder reflux for 4 days
9. temperatureAfter cooling
10. filtrationthe resulting crystals are filtered off
11. customto yield 56.4 g (74% of the