N-Boc-N-bis(PEG2-OH)

N-Boc-N-bis(PEG2-OH), is designed to provide a hydrophilic, flexible spacer that can be incorporated into targeted protein degradation constructs. Its PEG-based diol functionality supports solubility and compatibility with aqueous bioconjugation workflows, while the Boc-protected amine enables controlled stepwise coupling strategies. The linker’s balanced polarity and reactivity make it suitable for assembling PROTACs where efficient formation of stable conjugates and reliable linker presentation are critical. Detailed structural and reactivity considerations are provided below.

Structure: The molecule contains a Boc-protected nitrogen center connected to bis(PEG) arms terminated by hydroxyl groups. It features ether linkages within the PEG segments, flexible C–O and C–C connectivity, and a carbamate motif from the Boc group. Overall, it is polar and conformationally adaptable, supporting improved aqueous handling.

Reactivity: The terminal alcohols enable ether or ester-forming coupling routes commonly used in PROTAC assembly, including activation of hydroxyl groups followed by nucleophilic substitution or carbamate/ester bond formation. The Boc group can be removed under standard acid-mediated deprotection to reveal an amine for subsequent amide or urea coupling. Typical conditions use dry, inert-compatible solvents for coupling steps, with bases for deprotonation and controlled temperatures to minimize side reactions.