Synthesis and inotropic activity of pyrazolo[4,3-c]pyridine-4-ones and related compounds.

Two series of 3,6-dimethyl-1-phenyl-1H-pyrazolo4,3-c] pyridine-4-ones (5-9) and 3,6-dimethyl-1-phenyl-1H-pyrazolo4,3-c] pyridine-4-thiones (11-13) were prepared from dehydroacetic acid as starting material and evaluated for positive inotropic activity in vitro. Moreover, the activity of the synthesized compounds was compared with that of mirlinone as a reference. Among these compounds, the positive inotropic activity of 8a, 11a, and 12 were approximately 1.24, 1.77, and 1.11 times more potent, respectively, than that of mirlinone.