Methyl-PEG5-acid (CAS: 1347750-72-4) is a linear polyethylene glycol (PEG) derivative with the molecular formula C₁₄H₂₈O₉ and a molecular weight of approximately 340. Its structure consists of a pentaglyme chain terminated with a methoxy group (MPEG5) and an end carboxylic acid group (COOH), combining a hydrophilic PEG chain with a reactive carboxylic acid terminal group.
The production process typically involves ring-opening esterification of methoxypolyethylene glycol with maleic anhydride, catalyzed by pyridine. The reaction is carried out at 125°C for 6 hours, followed by ether purification to obtain a high-purity product. The carboxylic acid group can be activated with EDC/NHS to form amide bonds with amines or directly participate in esterification reactions.
This product is widely used in the biomedical field, such as drug carrier modification, antibody-drug conjugate (ADC) linkers, surface functionalization of nanomaterials, and polymer material modification (e.g., enhancing coating adhesion). Its low immunogenicity and high water solubility significantly improve the biocompatibility of materials.