The discovery and optimization of novel pyrrolo [3, 4-b] pyridin-7 (6H)-one MCH-R1 antagonists are described. A systematic SAR study probing the effects of aryl-, benzyl-and arylthio-substituents at the 2-position of the pyrrolo [3, 4-b] pyridin-7 (6H)-ones led to identification of the 2-[(4-fluorophenyl) thio] derivative 7b as a highly potent MCH-R1 antagonist. This compound also has favorable pharmacokinetic properties along with a ...