Heterocyclic derivatives

A heterocyclic derivative having the formula I

• wherein
• X1 and X2 are independently CH or N with the proviso that one of X1 and X2 is N;
• Y1-Y4 are CR1 or 1-2 of Y1 to Y4 are N;
• Z1-Z4 are CR2 or 1-2 of Z1 to Z4 are N;
• Each R1 and R2 is independently H, C1-6alkyl, C2-6alkenyl, C2-6alkynyl, C1-6alkoxy, C2-6alkenyloxy, C3-7cycloalkyl, C3-7cycloalkyloxy, OH, halogen or CN said C1-6alkyl and C1-6alkoxy being optionally substituted with one or more halogens;
• Each R3 is independently H, C1-6alkyl or C3-7cycloalkyl said C1-6alkyl and C3-7cycloalkyl being optionally substituted with one or more substituent independently selected from halogen, OH, CN, NR4R5 and C1-6alkoxy;
• R4 and R5 are independently H or C1-6alkyl or R4 and R5 together with the N to which they are bonded form a 4-7 membered heterocyclic ring;
• Ar is C6-10aryl or a 5-10 membered heteroaryl ring system comprising 1-3 heteroatoms independently selected from N, O and S, said C6-10aryl or 5-10 membered heteroaryl being optionally substituted with 1-3 R6;
• Each R6 is independently selected from C1-6alkyl, C2-6alkenyl, C2-6alkynyl, C1-6alkoxy, C2-6alkenyloxy, C3-7cycloalkyl, C3-7cycloalkyloxy, OH, halogen, CN and a 5-6 membered heteroaryl comprising 1-2 heteroatoms selected from N, O and S, said C1-6alkyl and C1-6alkoxy being optionally substituted with one or more halogens;
• m is 0 or 1 and
• n is 1 or 2
• or a pharmaceutically acceptable salt thereof.