Oxidation of arylacetylhydrazones of carbonyl compounds with lead tetraacetate

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 gives in good yields the 2H,5H‐1,3,4‐oxadiazoles 15 or substituted monoacetoxy‐ 17 and diacetoxyalkanes 18 . The reaction mechanisms are also discussed.