A solvent controlled three-component reaction of diazo compounds for the synthesis of hydrazone compounds under Brønsted acid catalysis

A novel Brønsted acid catalyzed three-component reaction of diazo compounds has been achieved from α-diazo ester, N -aminophthalimide and a solvent. An important feature of the method is that different products can be prepared selectively by modulating the reaction solvent. The reaction allows the synthesis of various amide hydrazone and α-hydroxyhydrazone products in moderate to good yield.