3OH

3OH, often written as 3-hydroxy or 3-OH, is a chemical shorthand for a hydroxyl group attached to the third carbon of a carbon skeleton. As a functional group, the 3-hydroxy substituent influences a molecule’s polarity, hydrogen bonding, and reactivity, and it appears in a variety of chemical contexts. In systematic nomenclature the position is indicated by the number, as in 3-hydroxypropanoic acid or 3-hydroxy-2-methylpentanoate, while in common usage the term 3-OH may refer to the presence of a hydroxyl at carbon 3 without specifying the entire structure.

In carbohydrate chemistry, the orientation of the 3-OH group helps define the identity and conformation of sugars, influencing ring form and stereochemistry. In lipid and fatty-acid chemistry, 3-hydroxy fatty acids are notable intermediates in biosynthetic pathways and can participate in ester or amide linkages within complex lipids. Metabolically, several 3-hydroxy compounds occur as intermediates or end products, such as 3-hydroxypropionic acid, a potential platform chemical, and beta-hydroxybutyrate (3-hydroxybutyrate), a ketone body produced during fat metabolism.

In polymer science, monomers bearing a 3-hydroxy group enable the synthesis of biodegradable polyesters and related polyhydroxyalkanoates, contributing to materials with varied mechanical properties and lifetimes. Overall, 3OH serves as a concise descriptor across chemistry and biochemistry for the presence and position of a hydroxyl group on the third carbon of a molecule.