t-Boc-N-Amido-PEG23-amine bears an amino group and Boc-protected amino group. The amino group readily react with carboxylic acids and activated esters to form amide bond. It can also react with carbonyl groups such as ketone and aldehyde under reductive amination condition to form C-N bond. The Boc group can be deprotected under mild acidic conditions to form the free amine, which can then undergo a second amide coupling. The PEG spacer increases the aqueous solubility of the resulting compound.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.