Bromoacetamido-PEG3-azide

Bromoacetamido-PEG3-azide is a bifunctional PEG-based linker designed for modular PROTAC synthesis, combining an azide handle for bioorthogonal conjugation with a bromoacetamide electrophile for controlled nucleophilic coupling. Its flexible poly(ethylene glycol) segment supports productive spatial arrangement between ligand moieties, which can improve the efficiency of ternary complex formation. The following sections describe the structure and practical reactivity features that enable researchers to assemble targeted protein degraders.

Structure: The linker contains a poly(ethylene glycol) chain providing conformational flexibility, terminated by an azide group and a bromoacetamide electrophile. It features an amide linkage, an alkyl bromide, and an azide functional group, with ether-rich segments that enhance polarity and solubility in common organic solvents.

Reactivity: The bromoacetamide portion is suited to nucleophilic substitution by thiols or amines under mild, controlled conditions, enabling formation of stable thioether or amide-linked intermediates for PROTAC construction. The azide group can be retained for subsequent copper-free or copper-catalyzed azide–alkyne cycloaddition with compatible partners, typically using anhydrous, oxygen-controlled solvents to minimize side reactions and preserve electrophile integrity.