# Can Ketones next to a Nitrogen hetero atom tautomerise?

I worry that the electronegative N will stabilise keto form so much that equilibrium will be so far towards keto it would be unreasonable to call the enolisiation process a factor

With a nitrogen adjacent to a carbonyl moiety, the functional group is an amide, and the tautomer involving a $\ce{C=N}$ bond is called an imidic acid. The amide is usually vastly more stable and typically predominates by many orders of magnitude. This can be rationalized by several considerations. First, the two tautomers differ by the exchange of a $\ce{C=O}$ bond with a $\ce{C=N}$ bond and an $\ce{N-H}$ with an $\ce{O-H}$, but the $\ce{C=O}$ bond is particularly strong, making the amide enthalpically more stable. Second, if you consider the resonance structures (i.e., mesomers) available to the two respective tautomers, the amide has a contributing structure in which a negative formal charge is placed on the more electronegative oxygen atom, whereas the corresponding structure in the imidic acid has the charge placed on a less electronegative nitrogen atom. Granted, resonance is not a real physical process, but examination of these structures gives some idea of the distribution of electron density in the frontier orbitals, which too points to favorable increase in stability for the amide. You can apply similar logic to the case of tautomers involving a $\ce{C=C}$ bond, where the ultimate conclusion should be the same (and the difference in stability between tautomers even greater).