Propargyl-PEG11-methane

Propargyl-PEG11-methane is a PEG-based linker designed for constructing PROTACs and other targeted protein degradation conjugates, where linker length, flexibility, and terminal reactivity are critical for productive ternary-complex formation. Its ether-rich backbone provides conformational mobility and improved solubility, while the propargyl handle enables efficient conjugation to ligands under standard bioconjugation workflows. The points below describe its structure and practical reactivity considerations in PROTAC synthesis.

Structure: The molecule comprises a propargyl-functional terminus connected to an extended poly(ethylene glycol) chain through a methane core. It contains multiple ether linkages that confer flexibility, polarity, and hydrophilicity, along with a terminal alkyne suitable for click-type coupling. Overall, it behaves as a PEGylated, ether-rich linker.

Reactivity: The terminal alkyne supports copper-catalyzed azide–alkyne cycloaddition for forming stable triazole linkages with azide-bearing PROTAC ligands. Typical conditions employ a Cu(I) catalyst generated in situ, with polar aprotic solvents and mild temperatures to preserve sensitive functional groups. Mechanistically, the reaction proceeds via activation of the alkyne and cycloaddition to the azide, enabling modular assembly of PROTACs without disrupting the PEG ether backbone.