Discovery of novel spiro[chromane-2,4′-piperidine] derivatives as potent and orally bioavailable G-protein-coupled receptor 119 agonists

[Display omitted] •The spiro-type scaffold was used as a novel linker-to-tail moiety of GPR119 agonists.•The rigid spiro-type scaffold enabled flexible and successful optimization.•Optimized (R)-29 exhibited a potent in vivo activity sufficient for a drug candidate. Herein, we describe the discovery, synthesis, and evaluation of a novel series of spiro[chromane-2,4′-piperidine] derivatives as G-protein-coupled receptor 119 agonists. Their initial design exploited the conformational restriction in the linker-to-tail moiety, which was a key concept in this study, to give lead compound 11 (EC50 = 369 nM, Emax = 82%). An extensive structure–activity relationship study resulted in the identification of the optimized drug candidate (R)-29 (EC50 = 54 nM, Emax = 181%). The defining structural features of the series were a terminal benzyl-type bulky substituent and a methylene linker between the sulfonyl and phenyl groups, both of which were in the head moiety as well as the spiro-type scaffold in the linker-to-tail moiety. An in vivo oral glucose-tolerance test using C57BL/6N mice showed that (R)-29 reduced glucose excursion at a dose of 3 mg/kg in a dose-dependent manner.