8-Azido-3,6-dioxaoctanoic acid tert-butyl ester (Azide-PEG2-COOtBu, N3-PEG2-COOtBu) is a monodisperse heterofunctional PEG with azide group and tert-butyl ester protected carboxylic group. The protected carboxyl (COOH) prevents self coupling or polymerization under standard acid/amine or acid/hydroxyl coupling conditions. Azide can be used for molecule conjugation by click chemistry. The protected acid can be regenerated by acidic or basic hydrolysis.
Heterobifunctional PEG reagents from NSP are generally employed as crosslinking agents or as spacers between two different chemical entities. The PEG moiety in the heterofunctional PEG derivatives provides water solubility, biocompatibility, and flexibility. Applications are especially geared towards the development of antibody drug conjugates.