Br-PEG4-NHBoc

This Br-PEG4-NHBoc linker is designed for modular construction of PROTAC conjugates, providing a polyethylene glycol spacer that supports controlled spatial presentation of reactive handles. Its bromide enables efficient attachment to nucleophilic partners, while the protected amine (NHBoc) offers a stable intermediate for subsequent coupling and deprotection. These features can improve synthetic flexibility and help optimize linker length and polarity in targeted protein degradation workflows, as detailed in the following sections.

Structure: The linker combines a terminal bromide with a PEG-based ether chain and a Boc-protected amine. It contains ether linkages along the PEG segment, an alkyl bromide at one terminus, and a carbamate protecting group on nitrogen, providing chemical stability under many coupling conditions.

Reactivity: The bromide functionality is well suited for nucleophilic substitution or related coupling strategies with amine, thiol, or other nucleophiles under standard organic synthesis conditions. The Boc group can be selectively removed using acid-mediated deprotection to reveal the free amine for amide or urea-forming reactions. Typical approaches use common polar aprotic solvents and base/acid systems compatible with PEG linkers.