α-Oxocarboxylic Acids

Several α-oxocarboxylic acids play key roles in metabolism in plants and animals. However, there are inconsistencies between the structures as commonly portrayed and the reported acid ionization constants, which result because the acids are predominantly hydrated in aqueous solution; that is, the predominant form is RC(OH)2COOH rather than the nominal RCOCOOH. We urge that this structure be more accurately reflected in tabulations by use of appropriate nomenclature and clear explanation. The combination of hydration and acid−base equilibria in these compounds provides good material for teaching and testing these concepts. After reviewing the facts on these equilibria, we provide several related problems for use in general or organic chemistry courses in the supporting information.