X-Ray and nuclear magnetic resonance structural study of acylglyoximes and related substances

Abstract

A series of reactions used in the literature to synthesize acylglyoximes were reinvestigated and the mixtures of products obtained resolved by chromatography. NMR spectroscopy revealed that some of the derivatives described in literature as dioximes actually have an isoxazoline structure. X-Ray analysis was employed to establish unequivocally the structures of syn-diacetylglyoxime and the (Z)-3-acetyl-5-hydroxy-4-hydroxyimino-5-methyl-4,5-dihydroisoxazole hemihydrate. In addition, the structure of the derivative produced by treatment of 5-hydroxy-4-hydroxyimino-3-methyl-5-phenyl-4,5-dihydroisoxazole with dinitrogen tetraoxide in dry diethyl ether is also described.