Substituted indol-2-yl-2, 4-pentadienamides having an action of inhibiting the biological activity of human osteoclast cells, a process for the preparation thereof, and a pharmaceutical composition comprising them

A compound of formula (I) or a salt thereof, or a solvate thereof, wherein R6 represents hydrogen, halo, trifluoromethyl; R7 represents hydrogen, halo; R8 represents hydrogen, C1-6alkyl, carboxy-C1-6alkyl; Rb represents wherein R1 represents C1-6alkyl, and Rs represents one of the following radicals: pyridinyl which can be substituted by C1-6alkyl, di-(C1-6alkyl) amino, C1-6alkoxy, halo, hydroxy-C1-6alkoxy, pyridyloxy, C1-6alkoxy-carbonyl-C1-6alkoxy, carboxy-C1-6alkoxy, C1-6alkoxy-C1-6alkoxy, di-(C1-6alkyl)-amino-C1-6alkoxy, oxo, di-(C1-6alkyl) amino-C1-6alkylamino; pyrimidinyl which can be substituted by C1-6alkoxy, oxo, di-(C1-6alkyl)-aminomethyleneamino, di-(C1-6alkyl)amino, C1-6acylamino, phenyl, amino, cyano; piperazinyl-C1-4alkyl, which can be substituted by benzoyl, benzoyl-benzoyl, C1-6alkoxy-phenyl, C1-6alkyl, pyrimidinyl, di-C1-6alkyl-phenyl, pyridyl, C1-6alkoxyphenyl, phenyl, halogenophenyl; piperidinyl which can be substituted by C1-6alkyl, mono- or di-hydroxy-C1-6alkyl, C1-6alkoxycarbonyl-C1-4alkyl; C6-10azabicycloalkyl which can be substituted by C1-6alkyl, hydroxy, phenyl, hydroxy-C1-6alkyl, C1-6acyloxy-C1-6alkyl, C1-6alkoxy-carbonyl; C6-10diazabicycloalkyl which can be substituted by C1-6alkyl; C6-10azabicycloalkyl-C1-6alkyl which can be substituted by C1-6alkyl; imidazolyl-C1-6alkyl; C8-12tricycloalkyl-amino-C1-6alkyl; di-(C1-6alkyl)amino-C1-6alkyl; di-(C1-6alkyl)amino-phenyl; 1-6alkyl-octahydroindolizinyl which can be substituted by C1-6alkyl; decahydro-pyrroloindolizynyl; octahydroquinolizinyl which can be substituted by C1-6alkyl; C5-8cycloalkyl which can be substituted by di-(C1-6alkyl)amino; pyrrolidinone-C1-6alkyl, a process for preparing such a compound, a pharmaceutical composition containing such a compound and the use of such a compound in medicine.