mPEG3-hydrazide

mPEG3-hydrazide is an mPEG-based hydrazide linker designed for constructing PROTACs and related targeted degradation conjugates. Its polyethylene glycol segment supports aqueous solubility and bioconjugation compatibility, while the terminal hydrazide provides a versatile handle for forming stable linkages to targeting ligands or intermediate scaffolds. The resulting conjugates can be engineered to tune steric presentation and overall physicochemical behavior, supporting efficient recruitment of E3 ligases in PROTAC workflows.

Structure: The molecule consists of an mPEG chain terminated by a hydrazide functional group, featuring an amide linkage within the hydrazide motif and ether linkages along the PEG backbone. This combination yields a flexible, highly solvated linker with hydrogen-bonding capability at the hydrazide site.

Reactivity: Hydrazide chemistry commonly enables coupling through condensation or acyl transfer approaches, including formation of hydrazone-type intermediates with aldehydes, followed by stabilization where appropriate. For PROTAC assembly, reactions are typically performed under mild, water-miscible conditions with buffered pH control to maintain hydrazide reactivity while limiting side reactions. Appropriate carbonyl partners and standard coupling catalysts (when required by the chosen synthetic route) are selected to drive selective bond formation.