A compound of general formula: in which R 1 represents a group selected from hydrogen, (C 1 -C 6)-alkyl, (C 3 -C 6)-cycloalkyl, 5- to 6-membered heterocycloalkyl, 5-to 10-membered heteroaryl, and phenyl wherein said (C 1 -C 6)-alkyl, (C 3 -C 6)-cycloalkyl, 5- to 6-membered heterocycloalkyl,5- to 10-membered heteroaryl, or phenyl is optionally substituted with one or two groups independently selected from cyano, halogen, amino, hydroxy, oxo, C 1 -C 3 -alkyl, (C 1 -C 4)-alkoxy, (C 1 -C 4)-alkylcarbonyl, mono-(C 1 -C 4)-alkylamino, di-(C 1 -C 4)-alkylamino, phenyl, (C 1 -C 4)-alkylsulfonyl, and (C 3 -C 6)-cycloalkyl, wherein each said C 1 -C 3 -alkyl, (C 3 -C 6)-cycloalkyl, and (C 1 -C 4)-alkoxy is optionally substituted with up to 5 fluorine atoms R 2 represents a group selected from hydrogen, cyano, halogen, (C 1 -C 4)-alkylsulfonyl, (C 1 -C 4)-alkyl, (C 3 -C 6)-cycloalkyl, and (C 1 -C 4)-alkoxy wherein said (C 1 -C 4)-alkyl, (C 3 -C 6)-cycloalkyl, or (C 1 -C 4)-alkoxy is optionally independently substituted with up to five fluorine atoms, cyano, or (C 1 -C 2)alkyl, wherein said (C 1- C 2)alkyl is optionally substituted with up to five fluorine atoms R 3, R 4, R 5, R 6, R 7 and R 8 represent a group independently selected from hydrogen, halogen, (C 1 -C 4)-alkyl and (C 1 -C 4)-alkoxy wherein each said (C 1 -C 4)-alkyl and (C 1 -C 4)-alkoxy is optionally independently substituted with up to five fluorine atoms, with the proviso that at least one of R 2, R 3, and R 4 represents H, X 1, X 2, X 3, X 4, X 5, X 6, represent N or C with the proviso that in each ring system maximally one X stands for N and R 5, R 6, R 7 and R 8 are present, provided that the designated atom's normal valency under the existing circumstances is not exceeded, and pharmaceutically acceptable salts thereof, solvates thereof and the solvates of the salts thereof. R 1 represents a group selected from hydrogen, (C 1 -C 6)-alkyl, (C 3 -C 6)-cycloalkyl, 5- to 6-membered heterocycloalkyl, 5-to 10-membered heteroaryl, and phenyl wherein said (C 1 -C 6)-alkyl, (C 3 -C 6)-cycloalkyl, 5- to 6-membered heterocycloalkyl,5- to 10-membered heteroaryl, or phenyl is optionally substituted with one or two groups independently selected from cyano, halogen, amino, hydroxy, oxo, C 1 -C 3 -alkyl, (C 1 -C 4)-alkoxy, (C 1 -C 4)-alkylcarbonyl, mono-(C 1 -C 4)-alkylamino, di-(C 1 -C 4)-alkylamino, phenyl, (C 1 -C 4)-alkylsulfonyl, and (C 3 -C 6)-cycloalkyl, wherein each said C 1 -C 3 -alkyl, (C 3 -C 6)-cycloalkyl, and (C 1 -C 4)-alkoxy is optionally substituted with up to 5 fluorine atoms wherein said (C 1 -C 6)-alkyl, (C 3 -C 6)-cycloalkyl, 5- to 6-membered heterocycloalkyl,5- to 10-membered heteroaryl, or phenyl is optionally substituted with one or two groups independently selected from cyano, halogen, amino, hydroxy, oxo, C 1 -C 3 -alkyl, (C 1 -C 4)-alkoxy, (C 1 -C 4)-alkylcarbonyl, mono-(C 1 -C 4)-alkylamino, di-(C 1 -C 4)-alkylamino, phenyl, (C 1 -C 4)-alkylsulfonyl, and (C 3 -C 6)-cycloalkyl, wherein each said C 1 -C 3 -alkyl, (C 3 -C 6)-cycloalkyl, and (C 1 -C 4)-alkoxy is optionally substituted with up to 5 fluorine atoms R 2 represents a group selected from hydrogen, cyano, halogen, (C 1 -C 4)-alkylsulfonyl, (C 1 -C 4)-alkyl, (C 3 -C 6)-cycloalkyl, and (C 1 -C 4)-alkoxy wherein said (C 1 -C 4)-alkyl, (C 3 -C 6)-cycloalkyl, or (C 1 -C 4)-alkoxy is optionally independently substituted with up to five fluorine atoms, cyano, or (C 1 -C 2)alkyl, wherein said (C 1- C 2)alkyl is optionally substituted with up to five fluorine atoms R 3, R 4, R 5, R 6, R 7 and R 8 represent a group independently selected from hydrogen, halogen, (C 1 -C 4)-alkyl and (C 1 -C 4)-alkoxy wherein each said (C 1 -C 4)-alkyl and (C 1 -C 4)-alkoxy is optionally independently substituted with up to five fluorine atoms, with the proviso that at least one of R 2, R 3, and R 4 represents H, X 1, X 2, X 3, X 4, X 5, X 6, represent N or C with the proviso that in each ring system maximally one X stands for N and R 5, R 6, R 7 and R 8 are present, provided that the designated atom's normal valency under the existing circumstances is not exceeded,