dihydroxyacid

Dihydroxyacid is a general term used in organic chemistry to describe any molecule that contains two hydroxyl groups (-OH) and at least one acidic functional group, typically a carboxyl group (-CO2H). As a class, dihydroxyacids can vary widely in size, substitution, and stereochemistry; common examples include dihydroxycarboxylic acids and dihydroxy acids derived from sugars and polyols. The two hydroxyl groups impart high polarity and usually promote solubility in water, while the carboxyl group provides acidity and enables reactions such as esterification and decarboxylation. Depending on structure, dihydroxyacids can be chiral and may exist as several stereoisomers.

In metabolism and biochemistry, dihydroxyacids may occur as intermediates or degradation products of carbohydrates and glycerol, arising by oxidation of vicinal diols or partial breakdown of polyols. Related species such as dihydroxyacetone and various sugar-derived dihydroxy acids are discussed in the same contextual framework, though not all such compounds are strictly classified as dihydroxyacids.

In chemical synthesis, dihydroxyacids serve as precursors for the production of diesters, lactones, or as building blocks for polymers, flavors, and fragrance compounds. Laboratory preparation often involves selective oxidation of glycols or other methods to introduce carboxyl groups onto diol substrates.

Because the term covers a wide range of structures, precise identification requires specifying the substituents and the exact carbon skeleton. See also related compounds such as dihydroxyacetone and various hydroxycarboxylic acids for context.