Synthesis and tautomeric structure of 2-[N-aryl-2-oxo-2-arylethanehydrazonoyl]-6-methyl-4(3H)-pyrimidinones

Two series of 2-(N-aryl-2-oxo-2-arylethanehydrazonoyl)-6-methyl-4(3H)-pyrimidinones () were prepared by coupling of diazotized anilines with 2-(aroylmethylene)-1,2-dihydro-6-methyl-4(3H)-pyrimidinones (). The spectral data of such compounds together with their 3-methyl analogs () indicated that they exist predominantly in the hydrazone tautomeric form.