Azide-PEG4-Tos linker containes an azide group and a tosyl group. The azide group can react with alkyne, BCN, DBCO via Click Chemistry to yield a stable triazole linkage. The tosyl group is a good leaving group for nucleophilic substitutions. The PEG spacer increases the aqueous solubility of the resulting compound.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.