RESUMO
Pd(II)-catalyzed C(sp(3))-H arylation of saturated heterocycles with a wide range of aryl iodides is enabled by an N-heterocyclic carbene (NHC) ligand. A C(sp(3))-H insertion step by the Pd(II)/NHC complex in the absence of ArI is demonstrated experimentally for the first time. Experimental data suggests that the previously established NHC-mediated Pd(0)/Pd(II) catalytic manifold does not operate in this reaction. This transformation provides a new approach for diversifying pharmaceutically relevant piperidine and tetrahydropyran ring systems.
Assuntos
Metano/análogos & derivados , Piperidinas/química , Piranos/química , Catálise , Ligantes , Metano/química , Estrutura MolecularRESUMO
A sequential triple C-H activation reaction directed by a pyrazole and an amide group leads to the well-controlled construction of sterically congested dihydrobenzo[e]indazole derivatives. This cascade reaction demonstrates that the often problematic competing C-H activation pathways in the presence of multiple directing groups can be harvested by design to improve step economy in synthesis. Pyrazole as a relatively weak coordinating group is shown to direct Csp3-H activation for the first time.
Assuntos
Pirazóis/química , Carbono/química , Catálise , Hidrogênio/química , Paládio , Pirazóis/síntese químicaRESUMO
SAR studies were conducted around lead compound 1 using high-throughput parallel solution and solid phase synthesis. Our lead optimization efforts led to the identification of several CCR2b antagonists with potent activity in both binding and functional assays [Compound 71 CCR2b Binding IC(50) 3.2 nM; MCP-1-Induced Chemotaxis IC(50) 0.83 nM; Ca(2+) Flux IC(50) 7.5 nM].