Spectroscopic studies of tautomeric systems-III

The IR and NMR spectra of a range of 2-arylhydrazones of 1,2,3-tricarbonyl compounds have been recorded. Compounds containing different end groups in the 1,2,3-tricarbonyl system can exist in two different tautomeric forms. The influence of electronic and steric factors on the structure of the preferred tautomer is discussed.