PROTAC 20S proteasome subunit β5 degrader 1 (compound 12f) is a targeted degrader of PROTAC for 20S proteasome subunit β5, with a DC 50 value of 0.11 μM in FaDu cells. PROTAC 20S proteasome subunit β5 degrader 1 disrupts the cell cycle, promotes apoptosis , and inhibits cell proliferation and migration in both FaDu and KM3/BTZ cells. PROTAC 20S proteasome subunit β5 degrader 1 can be used to study the resistance of pharyngeal cancer and multiple myeloma to Bortezomib (Pink: Target protein ligand ; Blue: E3 ligase ligand ; Black: Linker ).