ɑ-Butyric Acid-ω-Boc Amino PEG

PEG crosslinkers with Boc (tert-butyloxycarbonyl)-protected amino groups on one chain end. The Boc protecting group is stable in a wide range of conditions (including highly basic environments) but may be easily removed by (strong) acids such as TFA or at low pH in water to release the primary amine. The amine functional group at one end of the PEG linker molecule allows for selective and covalent attachment to other molecules with complementary functional groups, such as carboxylic acids or activated esters, aldehydes and epoxides. The newly formed bonds are amides, imines or secondary amines. Applicable for reversible or permanent crosslinking with PEG. The butyric acid endgroup is directly connected to the PEG chain via a very stable ether linkage. After activation it is used to conjugate the PEG derivative to nucleophilic substrates, mainly amines (to form amides) or hydroxyls/thiols (forming esters). PEG butyric acid active esters are one of the most hydrolytically stable PEG active esters. They can be used for pegylation in aqueous media without the need of a large excess of PEG.