Optimization of Pharmacokinetic and In Vitro Safety Profile of a Series of Pyridine Diamide Indirect AMPK Activators

A set of focused analogues have been generated around a lead indirect adenosine monophosphate-activated kinase (AMPK) activator to improve the rat clearance of the molecule. Analogues were focused on inhibiting amide hydrolysis by the strategic placement of substituents that increased the steric environment about the secondary amide bond between 4-aminopiperidine and pyridine-5-carboxylic acid. It was found that placing substituents at position 3 of the piperidine ring and position 4 of the pyridine could all improve clearance without significantly impacting on-target potency. Notably, trans-3-fluoropiperidine 32 reduced rat clearance from above liver blood flow to 19 mL/min/kg and improved the hERG profile by attenuating the basicity of the piperidine moiety. Oral dosing of 32 activated AMPK in mouse liver and after 2 weeks of dosing improved glucose handling in a db/db mouse model of Type II diabetes as well as lowering fasted glucose and insulin levels.