Abstract Oxidation of the title compounds 8, 9 with lead tetraacetate at room temperature gives a variety of products depending on the substituents on the carbonyl carbon atom. Thus, on oxidation of the aldehyde derivatives 8 1, 3, 4-oxadiazolo derivatives 10 are obtained in good yields. However in some cases formation of N-acetyl-N-arylacetyl-N′- benzoylhydrazines 11 is also observed, whereas oxidation of the ketone hydrazones 9 ...