Researchers from Ascentage Pharma Group International and Ascentage Pharma (Suzhou) Co. Ltd. have synthesized tricyclic compounds acting as inhibitor of apoptosis proteins (IAP) inhibitors reported to be useful for the treatment of cancer, AIDS, autoimmune disease, immune thrombocytopenia (idiopathic thrombocytopenic purpura), infections, psoriasis, rheumatoid arthritis, and inflammatory disorders, among others.