(S,R,S)-AHPC hydrochloride (Protein degrader 1 hydrochloride) is a building block in the synthesis of proteolysis-targeting chimera technologies (PROTACs).

Small molecule-induced protein degradation is an attractive strategy for the development of chemical probes.Protein degraders have the power to abrogate all of the functions of a drug target at once, including scaffolding functions which are difficult to target with small molecule inhibitors. A novel class of PROTACs that incorporate small molecule VHL ligands to successfully degrade HaloTag7 fusion proteins is developed. HaloPROTACs will inspire the development of future PROTACs with more drug-like properties. In HEK 293 cellsstably expressing GFP-HaloTag7,24 hour treatment with HaloPROTAC1 leads to less than 20% degradation, the longer HaloPROTAC2 leads to nearly 70% degradation of GFP-Halotag7 at 2.5 μM.HaloPROTACs containing protein degrader 1 leads to nearly 70% degradation of GFP-HaloTag7, when sufficiently long linkers are used