Reaction #1435698

Reaction equation

3-Methyl-1-phenylpyrazol-5-one

calcium hydroxide

tert-butylacetyl chloride

→

4-tert-Butyl-3-methyl-1-phenylpyrazol-5-one

Solvents

HCl

Conditions

Workup

1. 1
   Otherequipped with a stirrer
2. 2
   Temperaturereflux condenser
3. 3
   OtherDry
4. 4
   workup.DISTILLATIONdistilled dioxane (40 ml)
5. 5
   workup.ADDITIONwas added
6. 6
   workup.ADDITIONwas added
7. 7
   TemperatureThe mixture was heated
8. 8
   Temperatureto reflux for 4 hours
9. 9
   OtherA light brown precipitate formed immediately
10. 10
    Filtrationwhich was filtered off under suction
11. 11
    WashThe product was washed with water
12. 12
    Otherdried under vacuum at 50° C
13. 13
    OtherThe product was recrystallised from methanol
14. 14
    Otherto give an off-white crystalline solid, m.p 85–86° C.

Procedure

3-Methyl-1-phenylpyrazol-5-one (5 g; 0.029 mole) was placed in a flask equipped with a stirrer and reflux condenser. Dry and distilled dioxane (40 ml) was added by warming and to the clear solution calcium hydroxide (6.4 g; 0.086 mole) was added followed by drop wise addition of tert-butylacetyl chloride (4.8 ml; 0.034 mole). The mixture was heated to reflux for 4 hours and then poured into 2M HCl (200 ml) to decompose the calcium complex. A light brown precipitate formed immediately, which was filtered off under suction after refrigerating overnight. The product was washed with water and dried under vacuum at 50° C. The product was recrystallised from methanol to give an off-white crystalline solid, m.p 85–86° C.; 6.8 g (82%).

Source