dehydro

Dehydro is a chemical descriptor used in organic chemistry to indicate that a compound has been dehydrogenated, meaning it has lost hydrogen atoms relative to a related saturated form. The loss of hydrogen is typically accompanied by the formation of one or more double bonds, resulting in increased unsaturation. Dehydro appears as a prefix or part of a name in both common and systematic nomenclature to signal this structural relationship.

In nomenclature, dehydro denotes a dehydrogenated derivative rather than merely a dehydration (loss of water). It is often encountered in the names of biologically or chemically related compounds, such as dehydroascorbic acid, the oxidized form of vitamin C, and dehydroepiandrosterone (DHEA), a steroid with an additional double bond compared to a fully saturated counterpart. The term thus points to a specific structural feature—additional unsaturation—that influences reactivity and properties.

Biological and chemical contexts frequently involve dehydrogenation reactions. Enzymes called dehydrogenases remove hydrogen atoms from substrates, typically transferring them to electron carriers like NAD+ or FAD. These reactions are oxidation processes that can alter a molecule’s chemistry, including its polarity, conjugation, and biological activity.

Examples of usage include dehydroascorbic acid and dehydroepiandrosterone, among others. The precise meaning of dehydro in a given name is best understood by considering the full chemical structure and context, as the term serves as a descriptive indicator of hydrogen loss and resultant unsaturation rather than a standalone compound class.