6-Aminohexanoic Acid Dimer Impurity

6-Aminohexanoic Acid Dimer Impurity is a dimeric byproduct formed via intermolecular condensation between two 6-aminohexanoic acid monomers, linked by an amide bond between the terminal carboxyl group of one molecule and the primary amine of the other. The resulting structure comprises two linear aliphatic chains connected by a peptide linkage, with residual primary amine and carboxylic acid functionalities at opposing termini. This dimeric species arises during polymerization processes or API synthesis involving 6-aminohexanoic acid, where unreacted monomers undergo secondary coupling. It serves as a critical reference standard for HPLC-based quantification of dimeric impurities in 6-aminohexanoic acid-derived APIs.