Abstract: This invention comprises the use of compounds of formula (I) wherein the dotted line represents an optional bond; X is oxygen or sulfur; R1 is hydrogen, C1-12alkyl, Ar1, Ar2C1-6alkyl, quinolinylC1-6alkyl, pyridylC1-6alkyl, hydroxyC1-6alkyl, C1-6alkyloxyC1-6alkyl, mono- or di(C1-6alkyl)aminoC1-6alkyl, aminoC1-6alkyl, or a radical of formula -Alk1-C(═O)—R9, -Alk1-S(O)—R9 or -Alk1-S(O)2—R9; R2, R3 and R16 each independently are hydrogen, hydroxy, halo, cyano, C1-6alkyl, C1-6alkyloxy, hydroxyC1-6alkyloxy, C1-6alkyloxyC1-6alkyloxy, aminoC1-6alkyloxy, mono- or di(C1-6alkyl)aminoC1-6alkyloxy, Ar1, Ar2C1-6alkyl, Ar2oxy, Ar2C1-6alkyloxy, hydroxycarbonyl, C1-6alkyloxycarbonyl, trihalomethyl, trihalomethoxy, C2-6alkenyl; R4 and R5 each independently are hydrogen, halo, Ar1, C1-6alkyl, hydroxyC1-6alkyl, C1-6alkyloxyC1-6alkyl, C1-6alkyloxy, C1-6alkylthio, amino, hydroxycarbonyl, C1-6alkyloxycarbonyl, C1-6alkylS(O)C1-6alkyl or C1-6alkylS(O)2C1-6alkyl; R6 and R7 each independently ar