HOCH2COO

HOCH2COO is a shorthand notation used in chemistry to denote the glycolate moiety, specifically the glycolate anion. It represents the conjugate base of glycolic acid (hydroxyacetic acid) and is often encountered in salts such as sodium glycolate. The neutral parent molecule is glycolic acid, written as HOCH2COOH.

Structure and properties: HOCH2COO− features a primary alcohol group adjacent to a carboxylate group. In neutral to basic conditions, glycolic acid is deprotonated to form the glycolate anion, with the carboxylate carrying the negative charge. The molecule has an alpha-hydroxycarboxylate arrangement, which influences its reactivity in both organic synthesis and biological contexts. The pKa of glycolic acid is around 3.8, so at near-neutral pH the glycolate form is typically present as the conjugate base.

Occurrence and synthesis: Glycolate and its salts arise in various chemical and biological settings. They can be prepared by neutralizing glycolic acid with bases to give salts such as sodium glycolate. In metabolism, glycolate appears as an intermediate or byproduct in pathways involving hydroxyacetic acid derivatives and related compounds.

Reactions and applications: The glycolate moiety can participate in esterification to form glycolate esters, and the carboxylate group can engage in typical acyl substitution reactions. In coordination chemistry, glycolate can act as a ligand due to its carboxylate group. In biological systems, glycolate and related compounds are involved in metabolism and plant photorespiration processes. Glycolate esters and salts also find use in organic synthesis and various industrial applications.

Safety and handling: Salts and esters of glycolate are handled under standard chemical safety practices. Labeling and material safety data should be consulted for specific compounds.

See also: glycolic acid, glycolate oxidase, glycolate esters.