| abstract |
The invention relates to therapeutically active compounds of formula N @@ in which R1 to R4 denote hydrogen, alkyl, alkenyl, aryl, arylalkyl, carboxyalkyl, hydroxyalkyl or haloalkyl, or R2 and R3 form a ring of 5-7 carbon atoms, R5 to R9 mean hydrogen, alkyl, alkenyl, aryl, arylalkyl, acyl, hydroxy, alkoxy, alkoxycarbonyl, amino, acylamino, alkylamino, aryloxy, halogen, cyano, nitro, carboxy, alkylsulfonyl, sulfonamido or trifluoromethylacetate part of another group may be substituted, and to their pharmaceutically acceptable salts and esters. The compounds increase the sensitivity of cardiac muscle contractile proteins to calcium and are useful in the treatment of congestive heart failure. |