Amino-PEG5-amine

This amino-terminated polyethylene glycol linker is designed to provide a flexible, hydrophilic spacer for assembling PROTACs that couple an E3 ligase ligand to a target-binding moiety. Its bifunctional amine handles enable robust conjugation strategies while supporting favorable solubility and reduced nonspecific interactions. The linker’s adaptable geometry and chemical compatibility make it suitable for constructing well-defined degraders; detailed structural and synthetic considerations are provided below.

Structure: Amino-PEG5-amine is a bifunctional PEG-based linker featuring terminal primary amines connected through repeating ethylene glycol units. The structure contains ether linkages along the PEG backbone and amine functional groups at both ends, providing a flexible, water-compatible scaffold with hydrogen-bonding capability.

Reactivity: The terminal primary amines can be used for common PROTAC assembly reactions such as amide-bond formation with activated carboxylic acid derivatives, carbamate formation with activated carbonates, or reductive amination with aldehydes/ketones under standard organic conditions. Typical approaches employ coupling reagents or electrophilic activators, with polar aprotic solvents and controlled pH to preserve amine reactivity and maintain linker integrity.