HNO made-easy from photochemical cycloreversion of novel 3,5-heterocyclic disubstituted 1,2,4-oxadiazole-4-oxides

A variety of symmetric and asymmetric 3,5-heterocyclic disubstituted 1,2,4-oxadiazole-4-oxides have been prepared through cycloaddition of aromatic and heteroaromatic nitrile oxides to heteroaromatic amidoximes. A library of novel, fully characterized, 1,2,4-oxadiazole-4-oxides has been obtained as valuable precursors, upon photochemical activation, of new nitrosocarbonyl intermediates. The photochemical cycloreversion of the 1,2,4-oxadiazole-4-oxides was investigated from the computational point of view and the hydrolysis of the generated nitrosocarbonyl intermediates in water constituted the way for an easy-made HNO generation process because of the photochemical behavior of the parent compounds.