Patent ID: 7723391

Claim:
A compound of formula I: or a pharmaceutically acceptable salt thereof, wherein: Ar 1 is phenyl optionally substituted with one, two or three groups each selected independently from halo, halo-C 1-6 alkyl, C 1-6 alkyl and C 1-6 alkoxy; Ar 2 is phenyl optionally substituted once at the 4-position with halo, C 1-6 alkyl, cyano, halo-C 1-6 alkyl, C 1-6 alkoxy or —(CR a R b ) m —X—R 3 wherein: m is 0; X is —SO 2 — or —C(O)—; R 3 is C 1-6 alkyl or —NR 4 R 5 , and R 4 and R 5 each independently is: hydrogen; or C 1-6 alkyl; R 1 and R 2 are C 1-6 alkyl.