Facile synthesis of isoxazoles and pyrazoles from ß-diketohydrazones

Abstract

New 3,5-dimethyl-4-[(E)-4-(R1-phenyl)diazenyl]isoxazoles and 3,5-dimethyl-1-(R2-phenyl)-4-[(E)-(R1-phenyl)diazenyl]-1H-pyrazoles may be obtained by reaction of 3-[2-(R1-phenyl)hydrazono)]pentane-2,4-dione with H2NOH-HCl and R2-4-C6H4-NHNH2, respectively. The reactions were performed in ethanol as solvent and catalyzed by glacial acetic acid.