The present invention relates to a compound derived from indole, especially a therapeutically useful compound, characterized in that it is selected from compounds of formula (I) in which R1 represents a halogen or a trifluoromethyl group, R2 represents a hydrogen atom or a C1-C4 alkyl group, R3 represents an isopropyl (1-methylethyl) group or a tert-butyl (1,1-dimethylethyl) group and n=3 or 4 and pharmaceutically acceptable salts of said compounds of formula (I). Application: Treatment of neurodegenerative diseases and more particularly of Parkinson's disease.