Hydroxy-PEG4-t-butyl ester

Hydroxy-PEG4-t-butyl ester is a PEG linker containing a hydroxyl group with a t-butyl ester. The hydrophilic PEG spacer increases solubility in aqueous media. The hydroxyl group enables further derivatization or replacement with other reactive functional groups. The t-butyl protected carboxyl group can be deprotected under acidic conditions.

This heterobifunctional, PEGylated crosslinker features a hydroxyl group at one end and t-butyl-protected carboxylic acid at the other, which can be deprotected with acidic conditions. The hydrophillic PEG linker facilitates solubility in biological applications. Hydroxy-PEG4-t-butyl ester can be used for bioconjugation or as a building block for synthesis of small molecules, conjugates of small molecules and/or biomolecules, or other tool compounds for chemical biology and medicinal chemistry that require ligation. Examples of applications include its synthetic incorporation into antibody-drug conjugates or proteolysis-targeting chimeras (PROTAC^? molecules) for targeted protein degradation.