Hydrazine hydrate (1:1) → 3-Amino-5-tert-butylpyrazole

Participants

Reaction Steps

To 600 g of pivaloyl acetonitrile (compound I), there was added 800 ml of isopropanol. The mixture was heated with stirring, and 288 g of hydrazine hydrate was added dropwise thereto. The mixture was heated with stirring for 3 hours. After completion of the reaction, 400 ml of isopropanol was distilled off under reduced pressure. To the residue, there were added 2000 ml of ethyl acetate and saturated brine. The mixture was stirred and then left to stand for a while. The aqueous layer was removed, and the ethyl acetate layer was washed with saturated brine twice. The ethyl acetate solution was then dried over anhydrous magnesium sulfate, and then concentrated under reduced pressure. Subsequently, 2000 ml of n-hexane was added to the residue to precipitate a crystal. The crystal was recovered by filtration and dried. There was obtained 643 g (96.2%) of 3-amino-5-t-butylpyrazole (compound II). Melting point: 74.0° to 75.0° C.

Provenance & Evidence