Abstract: The present invention concerns the compounds having the formula N-oxides, salts, stereoisomeric forms, racemic mixtures, prodrugs, esters and metabolites thereof, wherein R1 and R8 each are H, optionally substituted C1-6alkyl, C2-6alkenyl, C3-7cycloalkyl, aryl, Het1, Het2; R1 may also be a radical of formula (R11aR11b)NC(R10aR10b)CR9—; t is 0, 1 or 2; R2 is H or C1-6alkyl; L is —C(?O)—, —O—C(?O)—, —NR8—C(?O)—, —O—C1-6alkanediyl-C(?O)—, —NR8—C1-6alkanediyl-C(?O)—, —S(?O)2—, —O—S(?O)2—, —NR8—S(?O)2; R3 is C1-6alkyl, aryl, C3-7cycloalkyl, C3-7cycloalkylC1-4alkyl, or arylC1-4alkyl; R4 is H, C1-4alkylOC(?O), carboxyl, aminoC(?O), mono- or di(C1-4alkyl)aminoC(?O), C3-7cycloalkyl, C2-6alkenyl, C2-6alkynyl or optionally substituted C1-6alkyl; A is C1-6alkanediyl, —C(?O)—, —C(?S)—, —S(?O)2—, C1-6alkanediyl-C(?O)—, C1-6alkanediyl-C(?S)— or C1-6alkanediyl-S(?O)2—; R5 is H, OH, C1-6alkyl, Het1C1-6alkyl, Het2C1-6alkyl, optionally substituted amino-C1-6alkyl; R6 is C1-6alkylO, Het1, Het1O, Het2, Het2O, aryl, arylO, C1-