1,3-Dihydro-1-R.sub.1 -3-R.sub.3 -6-PY-5-Q-2H-imidazo 4,5- b!pyridin-2- ones or -2-thiones or pharmaceutically-acceptable acid- addition salts thereof, which are useful as cardiotonic agents, where Q is hydrogen or lower- alkyl, R.sub.1 and R.sub.3 are each hydrogen, lower- alkyl, lower- hydroxyalkyl, 2,3-dihydroxypropyl, lower-alkoxyalkyl or Y- NB where Y is lower-alkylene and NB is di-(lower-alkyl)amino or 4- morpholinyl, at least one of R.sub.1 and R.sub.3 being hydrogen, and PY is 4- or 3-pyridinyl or 4- or 3-pyridinyl having one or two substituents, are prepared by reacting a 2-R.sub.3 NH-3-R.sub. 1 NH-5-PY-6-Q-pyridine with urea or carbonyldiimidazole to produce said -2- one or with an alkali metal xanthate, thiourea or thiocarbonyldiimidazole to produce said -2- thione. Also shown and claimed are cardiotonic compositions and a method for increasing cardiac contractility using said cardiotonic agents. Also shown are processes for preparing said intermediate 2-R.sub.3 NH-3-R.sub. 1 NH-5-PY-6-Q-pyridines and other intermediates used in said processes.
展开▼
