Patent ID: 7595405

Claim:
A compound of formula I: or a pharmaceutically acceptable salt thereof, wherein: R 1 is optionally substituted tetrazolyl; R 2 is optionally substituted phenyl, optionally substituted pyridinyl, optionally substituted pyrimidinyl, optionally substituted pyridazinyl or optionally substituted thiophenyl; R 3 is: hydrogen; C 1-6 alkyl; hetero-C 1-6 alkyl; or cyano; R 4 is: hydrogen; C 1-6 alkyl; or hetero-C 1-6 alkyl; or R 3 and R 4 together with the atom to which they are attached may form a C 3-6 carbocyclic ring; R 5 is heteroaryl selected from pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, pyrazolyl or thiazolyl, each of which may be optionally substituted once or twice with a group or groups independently selected from methyl, ethyl, n-propyl, fluoro, chloro, amino, methylamino and dimethylamino; and R 6 is hydrogen.