The present invention relates to compounds of general formula I wherein n, R1, R2, R3, R4, R5, R6, R7 and R8 are defined as stated hereinafter, the enantiomers, the diastereomers, the mixtures thereof and the salts thereof, particularly the physiologically acceptable salts thereof with organic or inorganic acids or bases, which have valuable properties, the preparation thereof, the pharmaceutical compositions containing the pharmacologically effective compounds, the preparation thereof and the use thereof.