m-PEG7-Boc

m-PEG7-Boc is a polyethylene glycol (PEG)-based linker bearing a Boc-protected functional group, designed to support controlled conjugation workflows used in PROTAC synthesis. Its PEG segment provides hydrophilic spacing that can improve solubility and reduce nonspecific interactions, while the Boc handle enables protected, stepwise attachment to targeting and E3 ligase-binding motifs. The following points describe the linker’s structure and practical reactivity considerations in detail.

Structure: The molecule consists of a PEG chain terminating in a Boc-protected group, providing an ether-rich, flexible scaffold. It features repeating ethylene oxide units connected by ether linkages, plus a Boc carbonate/urethane-type protecting group that contains carbonyl functionality and a tert-butyl moiety.

Reactivity: Boc groups are typically removed under mild acid conditions to generate a reactive amine for subsequent coupling. PROTAC assembly commonly proceeds by deprotecting to unveil the nucleophile, then forming amide or related linkages via standard coupling chemistries. Suitable approaches include activation of carboxylic acids with carbodiimide-based reagents (often with an additive) in polar organic solvents, or using pre-activated acyl intermediates, followed by purification to remove protecting-group byproducts.