DBCO-PEG3-amine

DBCO-PEG3-amine is a bifunctional PEG-based linker designed for efficient conjugation workflows commonly used in PROTAC construction and related targeted protein degradation platforms. Its DBCO (dibenzocyclooctyne) handle enables rapid, bioorthogonal azide–alkyne cycloaddition, while the terminal amine provides a versatile attachment point for coupling to ligands or intermediate fragments. The combination of a flexible hydrophilic PEG spacer and orthogonal reactivity supports robust synthesis, improved solubility, and modular assembly;

Structure: The linker contains a DBCO alkynyl moiety connected through a short poly(ethylene glycol) spacer to a primary amine. It features an aromatic-rich cyclooctyne core and ether-rich PEG segments, with stable carbon–carbon and carbon–nitrogen bonds, contributing to flexibility and enhanced aqueous compatibility.

Reactivity: The DBCO group undergoes strain-promoted azide–alkyne cycloaddition with azides under mild, catalyst-free conditions, typically in aqueous or mixed aqueous media. The primary amine can be used for amide bond formation or reductive amination strategies, depending on the complementary functional group on the partner ligand. Common coupling approaches employ activated carboxylic acids or amine-reactive derivatives, with standard organic solvents and base systems used to drive conjugation.