Thalidomide -piperidine-O-azetidine-acetic acid is a conjugate of E3 ligase ligand and linker , consisting of Thalidomide and the corresponding Linker. Thalidomide -piperidine-O-azetidine-acetic acid can serve as a Cereblon ligand to recruit CRBN protein and serve as a key intermediate for the synthesis of complete PROTAC molecules.