Discovery of a novel highly potent broad-spectrum heterocyclic chemical series of arenavirus cell entry inhibitors

We identified and explored the structure-activity relationship (SAR) of a novel heterocyclic chemical series of arenavirus cell entry inhibitors. Optimized lead compounds, including diphenyl-substituted imidazo[1,2-a]pyridines, benzimidazoles, and benzotriazoles exhibited low to sub-nanomolar potency against both pseudotyped and infectious Old and New World arenaviruses, attractive metabolic stability in human and most nonhuman liver microsomes as well as a lack of hERG K + channel or CYP enzyme inhibition. Moreover, the straightforward synthesis of several lead compounds (e.g., the simple high yield 3-step synthesis of imidazo[1,2-a]pyridine 37) could provide a cost-effective broad-spectrum arenavirus therapeutic that may help to minimize the cost-prohibitive burdens associated with treatments for emerging viruses in economically challenged geographical settings.

Discovery of Adamantane Carboxamides as Ebola Virus Cell Entry and Glycoprotein Inhibitors

We identified and explored the structure-activity-relationship (SAR) of an adamantane carboxamide chemical series of Ebola virus (EBOV) inhibitors. Selected analogs exhibited half-maximal inhibitory concentrations (EC₅₀ values) of ∼10-15 nM in vesicular stomatitis virus (VSV) pseudotyped EBOV (pEBOV) infectivity assays, low hundred nanomolar EC₅₀ activity against wild type EBOV, aqueous solubility >20 mg/mL, and attractive metabolic stability in human and nonhuman liver microsomes. X-ray cocrystallographic characterizations of a lead compound with the EBOV glycoprotein (GP) established the EBOV GP as a target for direct compound inhibitory activity and further provided relevant structural models that may assist in identifying optimized therapeutic candidates.

SAR studies of 4-acyl-1,6-dialkylpiperazin-2-one arenavirus cell entry inhibitors

Old World (Africa) and New World (South America) arenaviruses are associated with human hemorrhagic fevers. Efforts to develop small molecule therapeutics have yielded several chemical series including the 4-acyl-1,6-dialkylpiperazin-2-ones. Herein, we describe an extensive exploration of this chemotype. In initial Phase I studies, R1 and R4 scanning libraries were assayed to identify potent substituents against Old World (Lassa) virus. In subsequent Phase II studies, R6 substituents and iterative R1, R4 and R6 substituent combinations were evaluated to obtain compounds with improved Lassa and New World (Machupo, Junin, and Tacaribe) arenavirus inhibitory activity, in vitro human liver microsome metabolic stability and aqueous solubility.

Design and Synthesis of 5-Aryl-pyridone-carboxamides as Inhibitors of Anaplastic Lymphoma Kinase

Anaplastic lymphoma kinase (ALK) is a promising new target for therapy of certain cancers such as anaplastic large-cell lymphoma (ALCL) and inflammatory myofibroblastic tumor (IMT). We have identified a series of novel pyridones as kinase inhibitors of ALK by application of a stepwise process involving in vitro screening of a novel targeted library followed by iterative template modification based on medicinal chemistry insights and computational ranking of virtual libraries. Using this process, we discovered ALK-selective inhibitors with improved potency and selectivity. Herein the details of the design process and synthesis of these novel pyridones, along with their enzymatic and cell-based activity, are discussed.