Boc-NH-PEG2-NH-Boc contains two Boc protecting groups and a hydrophilic PEG spacer. The under mild acidic conditions, the Boc can be removed to form a free amine that can undergo amide coupling. The hydrophilic PEG linker increases the solubility of the compound in aqueous media.
AxisPharm offers 4000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.