The invention relates to a compound derived from indole, especially useful in therapy, characterised in that it is selected from i) the compounds of formula (I), and ii) the pharmaceutically acceptable salts of said compounds of formula (I) Rl, R2, R3, R4, R5, R6, R8, R9 and Cy being as defined in claim 1. The invention is applicable in the pharmaceutical field for treating neurodegenerative diseases, especially Parkinsons disease.