Leucine-rich repeat kinase 2 (LRRK2) inhibitors

A compound of formula IIa, or a pharmaceutically acceptable salt thereof, wherein:

• X is CH, CR1 or N;
• Y is CH, CR1 or N;
• R1 is independently selected from the group consisting of a C1-C3 alkyl, a C1-C3 haloalkyl, and a halogen;
• R2 is selected from a C1-C3 alkyl and an isotopically labelled C1-C3 alkyl;
• R3 is selected from the group consisting of a halogen, a cyano, and a C1-C3 haloalkyl;
• R4 is selected from the group consisting of a C1-C3 alkyl, an isotopically labelled C1-C3 alkyl, a C1-C3 haloalkyl, a O—C1-C3 alkyl, an isotopically labelled O—C1-C3 alkyl, a O—C1-C3 haloalkyl, and a O—C3-C6 cycloalkyl;
• n is 0, 1 or 2.