反应详情

Dissolve 2,4-pentanedione (5.09 g, 50.8 mmol) and benzylhydrazine dihydrochloride (10.91 g, 55.9 mmol) in acetic acid (40 mL). Slowly add triethylamine (15.6 mL, 0.112 mol) and stir the mixture for 18 hr. Concentrate the solution then dilute the residue with saturated aqueous sodium bicarbonate and extract 3 times with ethyl acetate. Dry (sodium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 40:60 hexanes:ethyl acetate), to give 1-benzyl-3,5-dimethyl-1H-pyrazole as a yellow oil (8.703 g, 92%).

1. concentrationConcentrate the solution
2. additionthen dilute the residue with saturated aqueous sodium bicarbonate
3. extractionextract 3 times with ethyl acetate
4. dry with materialDry (sodium sulfate)
5. filtrationfilter
6. concentrationconcentrate
7. custompurify
8. wash(silica gel chromatography, eluting with 40:60 hexanes:ethyl acetate)