Cyclopropane is the smallest cyclic compound with unique structural features and physicochemical properties, which is widely used in the design of small molecule drugs. In drug design, it is often used to increase activity, fix conformation and improve PK and water solubility. The introduction of cyclopropyl groups into drugs can change various properties of molecules, such as improving metabolic stability; increasing biological activity; enhancing drug efficacy; limiting polypeptide conformation and slowing down its hydrolysis; reducing plasma clearance; improving drug dissociation and many more. Cyclopropane rings are widely found in marketed drugs, including cardiovascular drugs, central nervous system (CNS) drugs, anticancer drugs, autoimmune and anti-inflammatory drugs.
Thienopyridines are similar in structure to quinoline and isoquinoline, and are a class of heterocyclic compounds with important physiological activity and medicinal value. Thienopyridines are a subclass of antiplatelet drugs that prevent platelet aggregation by binding to selected extracellular cysteine residues on the P2Y12 receptor located on the platelet membrane.