On the rearrangement of some Z-arylhydrazones of 3-benzoyl-5-phenylisoxazoles into 2-aryl-4-phenacyl-2H-1,2,3-triazoles: a kinetic study of the substituent effects in Boulton-Katritzky reactions

The rearrangement of eight new Z-arylhydrazones of 3-benzoyl-5-phenylisoxazoles (3d–k) into the relevant 2-aryl-4-phenacyl-2H-1,2,3-triazoles (4d–k) in dioxane/water solution at different proton concentrations has been quantitatively studied in a wide temperature range (293–333 K). The data collected together with some our previous ones on compounds 3a–c have allowed a deep study of the substituent effects on the course of the rearrangement, thus increasing our knowledge on the Boulton–Katritzky reactions in isoxazole derivatives and on the temperature effects on free energy relationships.