5-(Azide-PEG9-ethylcarbamoyl)pentanoic t-butyl ester linker contains an azide group and a t-butyl ester group. The azide group readily reacts with alkyne, BCN, DBCO through Click Chemistry to yield a stable triazole linkage. The deprotection of the t-butyl carboxyl group under acidic conditions affords a free carboxylic acid that can be used for coupling with amine-bearing molecules.
AxisPharm offers 4000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.