Thalidomide-5-propargyne-NH2 hydrochloride is primarily utilized in the field of medicinal chemistry and drug development. It serves as a key intermediate in the synthesis of targeted therapeutic agents, particularly in the design of proteolysis-targeting chimeras (PROTACs). These molecules are engineered to selectively degrade disease-causing proteins by leveraging the ubiquitin-proteasome system. This compound’s structure allows for the incorporation of functional groups that enhance binding affinity and specificity to target proteins, making it valuable in the development of treatments for cancers, autoimmune diseases, and other conditions driven by aberrant protein activity. Additionally, its propargyl group enables further chemical modifications through click chemistry, facilitating the creation of complex drug candidates with improved pharmacokinetic properties.