N-Benzyl-N-bis(PEG3-acid)

N-Benzyl-N-bis(PEG3-acid), is designed to provide a hydrophilic, flexible connection between targeting and recruiting ligands while supporting efficient formation of conjugates for targeted protein degradation workflows. Its ether-rich PEG segments promote solubility and can help tune linker length and conformational freedom, which are critical determinants of ternary-complex formation and degradation performance. The structure and reactivity considerations for constructing PROTACs using this linker are described in detail below.

Structure: The linker contains a benzyl-substituted tertiary amine core bearing two PEG3-acid arms, featuring multiple ether linkages and terminal carboxylic acid functionalities. It presents flexible polyether segments, amide-compatible acid reactivity, and a polar, water-dispersible character typical of PEG-containing linkers.

Reactivity: The terminal carboxylic acids enable standard PROTAC conjugation via amide or related acylation chemistries. Typical approaches include activating carboxylates with coupling reagents (for example, carbodiimides with additives) to form reactive acyl intermediates, followed by reaction with complementary nucleophiles on ligands (such as amines or hydrazides). Mild, anhydrous organic solvents and controlled pH are commonly used to minimize side reactions and preserve functional group integrity.