(S,R,S)-AHPC-PEG2-NH2 dihydrochloride

Background Introduction

(S,R,S)-AHPC-PEG2-NH2 dihydrochloride is a specialized bifunctional molecule widely utilized in the development of Proteolysis Targeting Chimeras (PROTACs). This compound features an (S,R,S)-AHPC-based E3 ligase ligand, which offers high affinity and selectivity for the von Hippel-Lindau (VHL) E3 ubiquitin ligase. The incorporation of the PEG2 linker enhances solubility and cell permeability, while the terminal amine (NH2) provides a functional handle for conjugation to target protein ligands. The strategic molecular design of (S,R,S)-AHPC-PEG2-NH2 dihydrochloride makes it a crucial building block in next-generation targeted protein degradation research and drug discovery.

Mechanism

(S,R,S)-AHPC-PEG2-NH2 dihydrochloride acts as a modular scaffold in PROTAC synthesis. Its (S,R,S)-AHPC moiety binds specifically to the VHL E3 ubiquitin ligase complex. The PEG2 linker provides optimal spatial flexibility, minimizing steric hindrance and improving the bioavailability of the resulting PROTAC molecules. The free amine group at the end of the linker allows for straightforward conjugation via amide coupling or other chemical strategies to a warhead ligand that targets the protein of interest. Once the bifunctional PROTAC brings the E3 ligase and the target protein into proximity, the ubiquitin-proteasome system is recruited, tagging the target protein for proteasomal degradation. This mechanism enables the selective and irreversible removal of disease-relevant proteins within cells.

Applications

(S,R,S)-AHPC-PEG2-NH2 dihydrochloride is extensively applied in the design and synthesis of PROTAC molecules aimed at therapeutic target validation, drug discovery, and chemical biology research. Researchers utilize this conjugate to develop customized protein degraders for cancer, neurodegenerative diseases, and other conditions involving pathogenic proteins. The product is especially valuable in creating VHL-based degraders and serves as a critical reagent for medicinal chemistry and structure-activity relationship (SAR) studies. Its applicability also extends to the development of molecular probes for investigating protein function and cellular mechanisms, enabling breakthroughs in next-generation therapeutics and targeted protein modulation.

• Polyethylene glycol (PEG2) linker improves aqueous solubility and pharmacokinetic properties for efficient PROTAC development.
• Amine-terminated design enables facile conjugation with target ligands, streamlining VHL-based PROTAC synthesis.

The (S,R,S)-AHPC-PEG2-NH2 dihydrochloride serves as a versatile E3 Ligase Ligand-Linker Conjugate in PROTACs, playing a crucial role in targeted protein degradation by bridging E3 ligases and target proteins. This compound facilitates selective and efficient degradation, enhancing therapeutic applications. The following provides a detailed description of this molecule's linker, ligand, and selection of target protein ligands.

Linker: The linker in (S,R,S)-AHPC-PEG2-NH2 dihydrochloride is a PEG2 chain, known for its moderate length and flexible nature, which allows for optimal spatial orientation between ligands. This flexibility aids in effective binding to target proteins and E3 ligases, though it is non-cleavable, ensuring stability throughout the degradation process.

Ligand: The ligand component of this molecule is derived from AHPC, a well-characterized cereblon (CRBN) ligand. Its stereochemistry is crucial for maintaining high affinity and specificity towards the CRBN E3 ligase, facilitating the recruitment of the ubiquitin-proteasome system for targeted protein degradation.

Reactive Site: The reactive site of (S,R,S)-AHPC-PEG2-NH2 dihydrochloride is the terminal amine group, which effectively couples with carboxylate or activated ester-functionalized target protein ligands. Recommended reaction types include amide bond formation, which ensures stable conjugation and efficient PROTAC assembly.

Recommended Target Protein Ligand: An optimal warhead for this molecule would be a small-molecule inhibitor or ligand with a carboxylate group, allowing for facile conjugation via amide bond formation. This compatibility ensures robust and selective degradation of the target protein, making it suitable for studying protein function or validating therapeutic targets in preclinical research settings.