Tautomers A Slight Digression

Organic reactions can be classified as addition, elimination, substitution, condensation, rearrangement, or isomerization. Redox reactions may belong to a number of these 

Acidity and basicity depend on the various factors that influence the position of the equilibrium between an acid HA and its conjugate base A. These include orbital effects, electronegativity, inductive effects, resonance effects, solvation hydrogen bonding, steric effects, and aromaticity. 

There are many other molecules where it is possible to write tautomers. The tautomerism between 2-hydroxypyridine, 8.14a, and 2-pyridone, 8.14b, is a model for our understanding of tautomerism in the bases of DNA and RNA. In writing tautomers, if there is an NH or OH attached to a double bond, it is often good to start by removing that proton in your thought experiment. However, removing a proton from carbon can also be useful as in the tautomerization 

Give a tautomer for each of the following species and comment on the likely relative stability of the species you produce. 

Both tautomers have reasonable structures, and the equilibrium between them is probably fairly equal. 

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