Bromo-PEG3-azide is a PEG linker containing a bromide group and an azide group. The hydrophilic PEG spacer increases solubility in aqueous media. The azide group can react with alkyne, BCN, DBCO via Click Chemistry to yield a stable triazole linkage. The bromide (Br) is a very good leaving group for nucleophilic substitution reactions.
Bromo-PEG4-azide is a PEG-based PROTAC linker that can be used in the synthesis of PROTACs[1]. Bromo-PEG3-azide is a click chemistry reagent, it contains an Azide group and can undergo copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules containing Alkyne groups. It can also undergo strain-promoted alkyne-azide cycloaddition (SPAAC) reactions with molecules containing DBCO or BCN groups.