Inotropic "A" ring substituted sulmazole and isomazole analogues.

A series of «A» ring substituted sulmazole and isomazole analogues have been prepared and evaluated as inotropic agents. pK A 's, protonation sites, and log P values were measured for selected compounds and their electronic properties were calculated. No simple correlation between inotropic activity activity and pK A , protonation site, or log P value was observed. However, in vitro inotropism did correlate with the calculated charge density of the «B» ring imidazo nitgrogen atom. The 6-position of sulmazole appeared to be the most tolerant toward substituents, the 6-amino derivative 7 being a more potent inotrope than sulmazole itself. 4-Methoxyisomazole 13 had comparable in vivo inotropic properties to those of isomazole