Substituted indole derivatives of formula (I) wherein the radicals have e. g. the following meaning: R1 is hydrogen, —C1-6-alkyl, R2 is hydrogen, —C1-6-alkyl or cycloC3-12-alkyl; R3 is OR R4 is hydrogen or halogen, R5 is hydrogen, —C1-6-alkyl R6 is hydrogen, —C1-6-alkyl R is hydrogen or —C1-6-alkyl; X is a group —C(O)CH2— or —CH═CH—; R7 is hydrogen are potent inhibitors of Abeta peptide polymerization and can be used for the treatment of e.g. Alzheimers disease or ocular disorders.