The present invention provides novel 4,5-disubstituted-7H-pyrrolo[2,3-d]pyrimidine derivatives of Formula I, and the pharmaceutically acceptable salts thereof wherein R1, R2, R3, R4 and R5 are as defined in the specification. The invention is also directed to pharmaceutical compositions comprising the compounds of formula I and to use of the compounds in the treatment of diseases associated with LRRK2, such as neurodegenerative diseases including Parkinson’s disease or Alzheimer’s disease, cancer, Crohn’s disease or leprosy.本發明提供新穎的式I之4,5-二取代-7H-吡咯并〔2,3-d〕嘧啶衍生物及其藥學上可接受之鹽類其中R1、R2、R3、R4及R5係如說明書中所界定者。本發明亦係關於包含式I化合物之藥學組成物及該化合物用於治療與LRRK2相關的疾病(例如:包括帕金森病或阿滋海默症之神經退化性疾病、癌症、克隆氏病(Crohn’s disease)、或痲瘋)之用途。