BackgroundTos-PEG4-t-butyl ester (Tos-PEG4-Boc) is a PROTAC linker, which refers to the PEG composition. Tos-PEG4-t-butyl ester (Tos-PEG4-Boc) can be used in the synthesis of a series of PROTACs, such as BI-3663 (HY-111546). BI-3663 is a highly selective PTK2/FAK PROTAC, with cereblon ligands to hijack E3 ligases for PTK2 degradation, and inhibits PTK2 with an IC50 of 18 nM.
Popow J, et al. Highly Selective PTK2 Proteolysis Targeting Chimeras to Probe Focal Adhesion Kinase Scaffolding Functions. J Med Chem. 2019 Mar 14;62(5):2508-2520.