| abstract |
A cardiotonic containing a compound represented by general formula (I) or, if any, a pharmaceutically acceptable salt thereof as the active ingredient, wherein X?1 and X2¿ are absent or each represents oxygen; A represents OH or C¿1?-C4 acyloxy; B represents hydrogen or is combined with A to form a bond; X represents oxygen, nitrogen, sulfur, etc.; R?1 and R2¿ represent each hydrogen, C¿1? - C4 alkyl, etc.; and R?3 and R4¿ represent each hydrogen, C¿1? - C4 alkyl, etc., or they may be combined together to represent 1,4-butylene, 1,5-pentylene, etc. The compound has potent activities of increasing cardiac contractility and reducing cardiac rate and is lowly toxic, thus being useful as a cardiotonic. |