Patent ID: 8252782

Claim:
A compound of formula (I), or pharmaceutically acceptable salt thereof; wherein R 1 is (C 1 -C 6 )alkyl substituted with 1 to 3 substituents selected from the group consisting of halo, hydroxy, (C 1 -C 6 )alkoxy, —NR 7 R 8 , —C(═O)NR 7 R 8 , and a 3 to 7 membered heterocycle, wherein R 7 and R 8 are independently hydrogen or (C 1 -C 6 )alkyl, wherein said heterocycle contains 1 to 3 heteroatoms independently selected from O, N, or S; R 2 is hydrogen or methyl; R 3 is hydrogen or methyl; R 4 is hydrogen, deuterium, or methyl optionally substituted with 1 to 3 substituents independently selected from F or Cl; R 5 is hydrogen, deuterium or methyl optionally substituted with 1 to 3 substituents independently selected from F or Cl; R 6 is H or —C(═O)OH; and X is C(H), C(F), C(Cl), or N.