Thalidomide-O-amido-C4-NH2 hydrochloride is primarily utilized in the field of medicinal chemistry and drug development. Its application is focused on the creation of targeted therapies, particularly in the treatment of cancer and inflammatory diseases. The compound is often employed as a building block in the synthesis of proteolysis-targeting chimeras (PROTACs), which are designed to degrade specific disease-causing proteins. This approach is especially valuable in oncology, where it helps in the selective degradation of proteins involved in tumor growth and survival. Additionally, its use extends to research exploring immunomodulatory drugs, where it aids in understanding and modulating immune responses in autoimmune disorders. The hydrochloride salt form enhances its solubility, making it more suitable for experimental and therapeutic applications.