HO-PEG1-CH2-COOMe

This HO-PEG1-CH2-COOMe linker is designed to provide a flexible, hydrophilic spacer for assembling targeted protein degradation (PROTAC) constructs. Its ether-containing PEG segment and ester functionality can support reliable conjugation strategies that preserve productive geometry between the ligand-binding moieties and the recruited E3 ligase. The subsequent sections describe the structural features and practical reactivity considerations for PROTAC synthesis and optimization.

Structure: The molecule contains a short poly(ethylene glycol) ether segment linked to a methylene spacer and a methyl ester. It features ether linkages that confer hydrophilicity and conformational flexibility, along with an ester carbonyl that provides a chemically addressable functional handle for downstream coupling.

Reactivity: The methyl ester can participate in standard ester-derivatization workflows used in linker installation, including nucleophilic substitution or conversion to more reactive carboxylate derivatives prior to amide or related bond formation. Typical PROTAC assembly employs inert atmospheres when needed, polar aprotic solvents for coupling steps, and base/activator systems consistent with amide-forming chemistries, enabling controlled formation of the final bioconjugate architecture.