Discovery of N-sulfonyl-7-azaindoline derivatives as potent, orally available and selective M4 muscarinic acetylcholine receptor agonists

We designed and synthesized novel N-sulfonyl-7-azaindoline derivatives as selective M4 muscarinic acetylcholine receptor agonists. Modification of the N-carbethoxy piperidine moiety of compound 2, an M4 muscarinic acetylcholine receptor (mAChR)-preferring agonist, led to compound 1, a selective M4 mAChR agonist. Compound 1 showed a highly selective M4 mAChR agonistic activity with weak hERG inhibition in vitro. A pharmacokinetic study of compound 1 in vivo revealed good bioavailability and brain penetration in rats. Compound 1 reversed methamphetamine-induced locomotor hyperactivity in rats (1-10 mg/kg, po).