反应详情

A mixture of 4-fluoro-N-methylbenzohydrazide (5.0 g), ethyl acetoacetate (4.84 g) and ethanol (140 ml) was stirred for 14 hrs. with heating under reflux. The reaction mixture was concentrated, water was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous magnesium sulfate and concentrated. The residue was subjected to silica gel column chromatography to give an oil from a fraction eluted with hexane-ethyl acetate (4:1-1:1, v/v). This oil was dissolved in ethanol (50 ml), 1,8-diazabicyclo[5.4.0]-7-undecene (0.5 ml) was added, and the mixture was stirred for 4 hrs. with heating under reflux. Water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous magnesium sulfate and concentrated to give ethyl 5-(4-fluorophenyl)-1,3-dimethyl-1H-pyrazole-4-carboxylate (3.41 g, yield 44%) as colorless crystals.

1. temperaturewith heating
2. temperatureunder reflux
3. concentrationThe reaction mixture was concentrated
4. additionwater was added
5. extractionthe mixture was extracted with ethyl acetate
6. washThe organic layer was washed with water
7. dry with materialdried over anhydrous magnesium sulfate
8. concentrationconcentrated
9. customto give an oil from a fraction
10. washeluted with hexane-ethyl acetate (4:1-1:1
11. dissolutionThis oil was dissolved in ethanol (50 ml)
12. addition1,8-diazabicyclo[5.4.0]-7-undecene (0.5 ml) was added
13. stirringthe mixture was stirred for 4 hrs
14. temperaturewith heating
15. temperatureunder reflux
16. additionWater was added to the reaction mixture
17. extractionthe mixture was extracted with ethyl acetate
18. washThe organic layer was washed with water
19. dry with materialdried over anhydrous magnesium sulfate
20. concentrationconcentrated