Patent ID: 8841336

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: C 1-6 alkyl; hetero-C 1-6 alkyl; halo-C 1-6 alkyl; N—C 1-6 alkylamino; N,N-di-(C 1-6 alkyl)-amino; C 3-7 cycloalkyl; aryl; heteroaryl; heterocyclyl; C 3-7 cycloalkyl-C 1-6 alkyl; heteroaryl-C 1-6 alkyl; heterocyclyl-C 1-6 alkyl; aryloxy-C 1-6 alkyl; or R 4 and R 5 together with the atom to which they are attached may form a C 3-6 carbocyclic ring that is optionally substituted with hydroxy; or R 4 and R 5 together with the atom to which they are attached may form a C 4-6 heterocyclic ring containing one or two heteroatoms each independently selected from O, N and S; or R 3 , R 4 and R 5 together with the atom to which they are attached may form a six-membered heteroaryl containing one or two nitrogen atoms, and which is optionally substituted with halo, amino or C 1-6 alkyl; R 6 is: hydrogen; C 1-6 alkyl; C 1-6 alkyloxy; halo; C 1-6 haloalkyl; or cyano; and R 7 and R 8 each independently is: C 1-6 alkyl; C 1-6 alkyloxy; halo; C 1-6 haloalkyl; or cyano; or one of R 7 and R 8 is: C 1-6 alkyl; C 1-6 alkyloxy; halo; C 1-6 haloalkyl; or cyano; and the other is hydrogen.