2-INDOLONES SUBSTITUTED IN 5 BY A CYCLIC HYDRAZIDE RADICAL, THEIR PREPARATION AND THEIR USE IN CARDIO-ACTIVE MEDICAMENTS

A compound of formula (I) or a pharmaceutically acceptable salt thereof, in which, R1 is hydrogen or lower alkyl; R2 is hydrogen or lower alkyl; R4 and R4 together form a group =N-Ra, or =CRaRb, where Ra is hydrogen, lower alkyl, aryl, aryloxy, lower alkylcarbonyl, arylcarbonyl, aryloxycarbonyl, lower alkoxy, lower alkoxy carbonyl, lower alkoxy carbonyl alkoxy, lower - thioalkoxy, hydroxy, nitrile, heterocyclyl, or -NRcRd, where Rc is hydrogen, lower alkyl, cycloalkyl, aryl, aralkyl, lower alkylcarbonyl, arylcarbonyl, aminocarbonyl, aminothiocarbonyl, aminoiminocarbonyl, lower alkoxycarbonyl, lower alkoxythiocarbonyl, aryloxycarbonyl, thiocarbonyl, nitrile, carboxyl, heterocyclyl or heterocyclylcarbonyl, and Rd is hydrogen or lower alkyl; Rb is hydrogen, lower alkyl, aryl, lower alkylcarbonyl, lower alkoxycarbonyl, nitrile or nitro; or R4 is -NH-Ra, in which Ra is as defined above, and R4 min is hydrogen or lower alkyl; each of R3 and R5 is independently hydrogen, lower alkyl, aryl, lower alkylcarbonyl, arylcarbonyl, aralkylcarbonyl, heterocyclylcarbonyl, optionally substituted aminocarbonyl, lower alkoxycarbonyl or aryloxycarbonyl; R6 is hydrogen, lower alkyl or halogen; and A is sulphur, oxygen, -NH- or -CH2-, is useful for the treatment of heart disease.