Discovery of 4-alkoxy-6-methylpicolinamide negative allosteric modulators of metabotropic glutamate receptor subtype 5
Publication date: Available online 10 November 2018
Source: Bioorganic & Medicinal Chemistry Letters
Author(s): Andrew S. Felts, Katrina A. Bollinger, Christopher J. Brassard, Alice L. Rodriguez, Ryan D. Morrison, J. Scott Daniels, Anna L. Blobaum, Colleen M. Niswender, Carrie K. Jones, P. Jeffrey Conn, Kyle A. Emmitte, Craig W. Lindsley
This letter describes the further chemical optimization of VU0424238 (auglurant), an mGlu5 NAM clinical candidate that failed in non-human primate (NHP) 28 day toxicology due to accumulation of a species-specific aldehyde oxidase (AO) metabolite of the pyrimidine head group. Here, we excised the pyrimidine moiety, identified the minimum pharmacophore, and then developed a new series of saturated ether head groups that ablated any AO contribution to metabolism. Putative back-up compounds in this novel series provided increased sp3 character, uniform CYP450-mediated metabolism across species, good functional potency and high CNS penetration. Key to the optimization was a combination of matrix and iterative libraries that allowed rapid surveillance of multiple domains of the allosteric ligand.