The invention relates to a method of treating or preventing Parkinsons disease in a subject comprising administering a compound of Formula I wherein, R1 is –NHC(O) C3-6 cycloalkyl and R2 is hydrogen or R1 and R2 along with the carbon atoms to which they are attached form a six membered aromatic ring, wherein the ring is substituted with one or more groups selected from hydrogen, halogen and C1-6 alkyl R3 and R4 are independently selected from group comprising hydrogen, halogen, C1-3 alkyl, OC1- 3 alkyl, NO2, SC1-3 alkyl, C1-3 haloalkyl, OC1-3 haloalkyl, and SC1-3 haloalkyl or a pharmaceutically acceptable salt thereof.
