Thalidomide-NH-C10-Boc (compound S20) is a conjugate of the E3 ubiquitinase ligand Thalidomide and PROTAC Linker , which can recruit Cereblon ubiquitinase. Thalidomide-NH-C10-Boc can couple the target protein ligand through the PTOTAC Linker to synthesize PROTAC molecules with degradation effects. For example, Thalidomide-NH-C10-Boc can couple with the ligand EP300/CBP ligand 2 to produce the PROTAC molecule dCE-2.