N- (acid-PEG10) -N-bis (PEG10-azide)

N- (acid-PEG10) -N-bis (PEG10-azide) is a very popular PEG reagent containing a terminal carboxylic acid and two azide groups. The hydrophilic PEG spacer increases solubility in aqueous media. The azide groups can react with alkyne, BCN, DBCO via Click Chemistry to yield a stable triazole linkage. The terminal carboxylic acid can react with primary amine groups in the presence of activators (e.g. EDC, or HATU) to form a stable amide bond.