mPEG7-bromide

This mPEG7-bromide is a polyethylene glycol (PEG) alkylating linker designed for efficient installation of PEG chains onto nucleophilic partners commonly used in PROTAC building blocks. Its bromide leaving group supports robust ether/alkylation-style conjugation, enabling improved solubility, reduced nonspecific interactions, and tunable linker properties that can enhance targeted protein degradation workflows. The structure and reactivity considerations for PROTAC-compatible synthesis are described in detail below.

Structure: mPEG7-bromide comprises a methoxy-terminated PEG chain bearing a terminal bromide. It features a polyether backbone with ether linkages and a primary alkyl bromide functional group, providing a flexible, hydrophilic scaffold suitable for bioconjugation and linker engineering in PROTAC constructs.

Reactivity: The terminal bromide enables nucleophilic substitution reactions, including alkylation of alcohols, thiols, or amines to form PEG ethers or related linkages, typically under base-mediated conditions. Common approaches use polar aprotic solvents to promote SN-type displacement, with reaction rates influenced by nucleophile strength and temperature. For PROTAC assembly, protect sensitive groups as needed and optimize stoichiometry to minimize PEG chain scrambling or side reactions.