Synthesis of Pyrazolone Derivatives. I

Synthesis of 4-Formylantipyrine and Some of Its Reactions

Abstract

As a possible intermediate for the preparation of antipyrine derivatives of therapeutic value, 4-f ormylantipyrine was prepared by treating antipyrine either with dirnethylformamide or formyl methylanilide in the presence of phosphoryl chloride. The yields were 88.1% and 53.2%, respectively. As an aldehyde, this compound condensed with malonic acid, nitromethane, hippuric acid, and diketopiperazine with separation of water. However, benzoin and Cannizzaro type of reactions failed to give the expected compounds, (VI) and (VII) being the chief products, respectively. Several other derivatives of 4-formylantipyrine were also prepared, none of which, however, showed properties of any interest from physiological view point.