Synthesis and SAR development of novel mGluR1 antagonists for the treatment of chronic pain.

High throughput screening identified the pyridothienopyrimidinone 1 as a ligand for the metabotropic glutamate receptor 1 (mGluR1=10 nM). Compound 1 has an excellent in vivo profile; however, it displays unfavorable pharmacokinetic issues and metabolic stability. Therefore, using 1 as a template, novel analogues (10i) were prepared. These analogues displayed improved oral exposure and activity in the Spinal Nerve Ligation (SNL) pain model.