N-methyl-N-(t-Boc)-PEG4-acid linker contains a Boc protected methylamino group and a terminal carboxylic acid. The methylamino functional group released by a mild acidic Boc de-protection can undergo amide coupling with activated carboxylic acid esters, such as NHS, PFP and TFPs. The terminal carboxylic acid readily reacts with primary and secondary amines under EDC, DCC and HAtU coupling conditions to form stable amide bonds. The PEG spacer increase 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.