An easy access to 2-oxohydrazones via electrophilic α-p-tolylhydrazonylation of ketone enolates with tert-butyl p-tolylazo sulfide

Article abstract of DOI:10.1016/S0040-4020(01)89426-6

The title reaction conveniently furnishes, as the sole or main products, α-(p-tolylhydrazono)ketones or their N-methylderivatives (H⁺ or MeI quenching of the final mixture, respectively). Although the method fails with ketones having a secondary alkyl group bonded to the carbonyl, yields are otherwise more than satisfactory and particular interest is attached to the hydrazonylation of the methyl group in methyl ketones.