Imidazo[1,2-a]pyridines. Synthesis and inotropic activity of new 5-imidazo[1,2-a]pyridinyl-2(1H)-pyridinone derivatives

Article abstract of DOI:10.1248/cpb.39.1556

A series of 1,2-dihydro-5-imidazo[1,2-a]pyridinyl-2(1H)-pyridinones was synthesized and evaluated for positive inotropic activity. 1,2-Dihydro-5-imidazo[1,2-a]pyridin-6-yl-6-methyl-2-oxo-3- pyridinecarbonitrile (11a) hydrochloride monohydrate (E-1020) was found to be a potent and selective inhibitor of phosphodiesterase III and a long-acting, potent, orally active positive inotropic agent. Additional imidazo[1,2-a]pyridin-2-yl (3a), -3-yl (16), -7-yl (20) and -8-yl (24a) compounds were also prepared. Altering the pyridine substitution from the 2-position to the 6-position produced a 2-fold increase in the i.v. cardiotonic potency (ED₅₀) from 52 to 23 μg/kg, while substitution at the 3-, 7- or 8-position reduced potency. In the 2-positional isomers, introduction of halogen groups enhanced the activity and 3-chloro-1,2-dihydro-5-(6-fluoroimidazo[1,2-a]pyridin-2-yl)-6-methyl-2(1H)- pyridinone (3a) was the most potent (i.v. ED₅₀ 11 μg/kg) in this seris. E-1020 is presently under development for the treatment of congestive heart failure.

Full text of DOI:10.1248/cpb.39.1556

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service

NII-Electronic Library Service