Thalidomide-O-amido-C4-NH2 hydrochloride, a synthesized E3 ligase ligand-linker conjugate, combines the cereblon ligand derived from Thalidomide with a linker and is commonly used in the synthesis of PROTACs[1].

Thalidomide-O-amido-C4-NH2 (Compound 41) is an amine intermediate that serves as a heterobifunctional PROTAC BET degrader. BET family proteins (BRD2, BRD3, BRD4, and BRDT) are key epigenetic readers involved in gene transcription regulation and are therapeutic targets for cancer and other diseases. Heterobifunctional small-molecule BET degraders have been developed using the PROTAC approach to induce BET protein degradation[1]. Thalidomide-O-amido-C4-NH2 functions as a degron-linker (Compound DL6-TL), where the linker binds to at least one degron and targeting ligand. The degron can bind to an ubiquitin ligase such as cereblon, and the targeting ligand binds to the targeted proteins[2].