ɑ-NHS-ω-Tritylthio PEGs

PEG butyric acid NHS derivatives have a C4 aliphatic chain directly attached to PEG and the NHS active ester is a useful reagent to pegylate proteines, peptides or any other surfaces with a free primary amino group to form stable amide bonds. PEG tritylthio derivatives feature a protected thiol at one chain end. Trityl groups are easily removed with acid. Pure TFA or TFA/DCM mixtures cleave trityl from thiols quantitatively.