반응 #58898

반응 방정식

4-fluoro-N-methylbenzohydrazide

ethyl acetoacetate

→

ethyl 5-(4-fluorophenyl)-1,3-dimethyl-1H-pyrazole-4-carboxylate

수율 44.0%

용매

ethanol

반응 조건

후처리

1. 1
   온도with heating
2. 2
   온도under reflux
3. 3
   농축The reaction mixture was concentrated
4. 4
   workup.ADDITIONwater was added
5. 5
   추출the mixture was extracted with ethyl acetate
6. 6
   세척The organic layer was washed with water
7. 7
   건조dried over anhydrous magnesium sulfate
8. 8
   농축concentrated
9. 9
   기타to give an oil from a fraction
10. 10
    세척eluted with hexane-ethyl acetate (4:1-1:1
11. 11
    workup.DISSOLUTIONThis oil was dissolved in ethanol (50 ml)
12. 12
    workup.ADDITION1,8-diazabicyclo[5.4.0]-7-undecene (0.5 ml) was added
13. 13
    workup.STIRRINGthe mixture was stirred for 4 hrs
14. 14
    온도with heating
15. 15
    온도under reflux
16. 16
    workup.ADDITIONWater was added to the reaction mixture
17. 17
    추출the mixture was extracted with ethyl acetate
18. 18
    세척The organic layer was washed with water
19. 19
    건조dried over anhydrous magnesium sulfate
20. 20
    농축concentrated

실험 절차

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.

출처