N-(azide-PEG10)-N-(PEG10-N-boc)-N-(PEG10-t-butyl ester) is a trifunctional PEG linker with an azide, a Boc-protected amine, and a t-butyl ester. The azide can be used in click chemistry with terminal alkynes and strained cyclooctynes like DBCO or BCN. t-Butyl esters can be deprotected using acidic or basic conditions to allow for amide coupling or esterification. Finally the Boc-protecting group can be removed with acid, allowing the primary amine to engage in reactions with carboxylic acids, aldehydes or ketones to form stable bonds with other molecules.
