Synthesis and structure of 5-hydrazino- and 5-hydroxyamino-3-aryl-2-pyrazolines and-2-isoxazolines

It was established by the methods of 1H and 13C NMR spectroscopy that the oximohydrazones and bis(hydrazones) of aroylacetic aldehydes exist in the form of the corresponding 5-hydrazino- and 5-hydroxyamino-3-aryl-2-pyrazolines and -2-isoxazolines. The features of the aromatization of these compounds to the corresponding pyrazoles and isoxazoles were studied. Data on the mass-spectral study of the 5-hydroxyamino-2-pyrazoline-5-hydrazino-2-isoxazoline tautomerism in the gas phase are presented.