Acetic Anhydride → 3-(4-Acetylaminophenyl)-2-pyrazolin-5-one

Participants

Reaction Conditions

Reaction Steps

In 440 ml of acetonitrile was dissolved 146 g of ethyl p-aminobenzoylacetate, and 70 ml of acetic anhydride was added dropwise to the solution at 40° C. After reacting at 40° C. for 1 hour, 48.8 g of 80% hydrazine hydrate was added thereto dropwise. After heat generation subsided, the reaction was further continued at a temperature between 55° C. and 60° C. for 1 hour. The reaction mixture was cooled to 5° C., and the precipitated crystals were filtered to yield 148 g of 3-(4-acetylaminophenyl)-2-pyrazolin-5-one as gray crystals having a melting point of 254° to 258° C.

Provenance & Evidence