Boc-NH-PEG2-NH-Boc contains two Boc protecting groups and a hydrophilic PEG spacer. The under mild acid condition, the boc can be removed to form free amine that can undergo amide coupling. The hydrophilic PEG linker increases the solubility of the compound in aqueous media.
Axispharm offers 3000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.