Reaction #452450

Reaction equation

Hydrazine hydrate

pivaloylacetonitrile

→

3-amino-5-t-butylpyrazole

Yield 96.4%

Solvents

Isopropanol

isopropanol

Conditions

Workup

1. 1
   Temperatureheating
2. 2
   Temperatureheating
3. 3
   workup.STIRRINGstirring
4. 4
   workup.DISTILLATIONwas distilled off under reduced pressure
5. 5
   workup.ADDITIONEthyl acetate 2000 ml and a saturated salt aqueous solution were added to a residue
6. 6
   workup.STIRRINGstirring
7. 7
   OtherAfter leaving
8. 8
   Otheran aqueous layer was removed
9. 9
   Washan ethyl acetate layer was washed twice with the saturated salt aqueous solution
10. 10
    Dryingby drying an ethyl acetate solution over magnesium sulfate anhydrous
11. 11
    ConcentrationThis ethyl acetate solution was concentrated under reduced pressure
12. 12
    workup.ADDITIONn-hexane 2000 ml was added to a residue
13. 13
    Otherto precipitate crystal
14. 14
    FiltrationThis crystal was filtered off
15. 15
    Otherdried

Procedure

Isopropanol 800 ml was added to pivaloylacetonitrile 600 g and heating and stirring were applied. Hydrazine hydrate 288 g was dropped thereto and heating and stirring were applied for 3 hours. After finishing the reaction, isopropanol 400 ml was distilled off under reduced pressure. Ethyl acetate 2000 ml and a saturated salt aqueous solution were added to a residue and stirring was applied. After leaving for standing for a while, an aqueous layer was removed and an ethyl acetate layer was washed twice with the saturated salt aqueous solution, followed by drying an ethyl acetate solution over magnesium sulfate anhydrous. This ethyl acetate solution was concentrated under reduced pressure and then n-hexane 2000 ml was added to a residue to precipitate crystal. This crystal was filtered off and dried, whereby 3-amino-5-t-butylpyrazole (Compound (A)) 643 g (96.2%) was obtained. The melting point was 74.0 to 75.0° C.

Source