A Decarboxylative Cross-Coupling Platform To Access 2-Heteroaryl Azetidines: Building Blocks with Application in Medicinal Chemistry.

Photoredox-transition metal dual catalysis provides a unique platform for constructing sp3-rich chemical matter. Here, we report a nickel-catalyzed cross-coupling of commercially available or easily prepared redox-active NHP azetidine-2-carboxylates with commercially available heteroaryl iodides to yield 2-heteroaryl azetidines. This "off-the-shelf" approach yielded products amenable to diversification giving access to novel saturated heterocyclic scaffolds useful for medicinal chemistry programs. An alternative mechanism for Hantzsch ester within nickel-catalyzed cross-coupling of heteroaryl halides and α-amino radicals is also presented.

Discovery of a Novel Class of Imidazo[1,2-a]Pyridines with Potent PDGFR Activity and Oral Bioavailability.

The in silico construction of a PDGFRß kinase homology model and ensuing medicinal chemistry guided by molecular modeling, led to the identification of potent, small molecule inhibitors of PDGFR. Subsequent exploration of structure-activity relationships (SAR) led to the incorporation of a constrained secondary amine to enhance selectivity. Further refinements led to the integration of a fluorine substituted piperidine, which resulted in significant reduction of P-glycoprotein (Pgp) mediated efflux and improved bioavailability. Compound 28 displayed oral exposure in rodents and had a pronounced effect in a pharmacokinetic-pharmacodynamic (PKPD) assay.

The discovery of furo[2,3-c]pyridine-based indanone oximes as potent and selective B-Raf inhibitors.

Virtual and high-throughput screening identified imidazo[1,2-a]pyrazines as inhibitors of B-Raf. We describe the rationale, SAR, and evolution of the initial hits to a series of furo[2,3-c]pyridine indanone oximes as highly potent and selective inhibitors of B-Raf.