Patent ID: 8168815

Claim:
A compound of structural formula Ia: or a pharmaceutically acceptable salt thereof; wherein X is CH; R 1 is selected from the group consisting of (a) C 1-3 alkyl optionally substituted with 1-3 halogens and optionally with one group selected from —OH, —OC 1-3 alkyl optionally substituted with 1-3 halogens, —SO x C 1-3 alkyl, and —CN, (b) —C(═O)H, (c) —C(═O)C 1-3 alkyl optionally substituted with 1-3 halogens, (d) —HC═NOH, (e) —(CH 3 )C═NOH, (f) —HC═NOC 1-3 alkyl optionally substituted with 1-3 halogens, (g) —(CH 3 )C═NOC 1-3 alkyl optionally substituted with 1-3 halogens, (h) —C(═O)OC 1-3 alkyl optionally substituted with 1-3 halogens, (i) —C(═O)NHR 6 , (j) —CH═CH-Phenyl wherein —CH═CH— is optionally substituted with 1-2 substituents independently selected from halogen and C 1-2 alkyl optionally substituted with 1-3 F, (k) —CH 2 CH 2 -Phenyl wherein —CH 2 CH 2 — is optionally substituted with 1-4 substituents independently selected from halogen and C 1-2 alkyl optionally substituted with 1-3 F, (l) Phenyl, (m) -HET-Phenyl, wherein HET is a 5- or 6-membered heteroaromatic ring containing 1-3 heteroatoms selected from O, N and S, (n) —C≡C-Phenyl, and (o) —CH 2 -Phenyl, wherein the —CH 2 — group of —CH 2 -Phenyl is optionally substituted with 1-2 substituents independently selected from halogen and C 1-2 alkyl optionally substituted with 1-3 F, wherein Phenyl and HET in all occurrences are optionally substituted with 1-3 substituents independently selected from (i) halogen, (ii) —C(═O)OC 1-3 alkyl optionally substituted with 1-3 halogens, (iii) —C(—O)OH, (iv) C 1-3 alkyl optionally substituted with 1-3 halogens, (v) —OC 1-3 alkyl optionally substituted with 1-3 halogens, (vi) —SO x Me, and (vii) —SO 2 NH 2 ; R 3 is halogen; R 6 is selected from the group consisting of H, C 1-3 alkyl optionally substituted with 1-3 halogens, Phenyl, and —CH 2 -Phenyl, wherein Phenyl in both occurrences is optionally substituted with 1-3 substituents independently selected from (i) halogen, (ii) —C(═O)OC 1-3 alkyl optionally substituted with 1-3 halogens, (iii) —C(═O)OH, (iv) C 1-3 alkyl optionally substituted with 1-3 halogens, and (v) —OC 1-3 alkyl optionally substituted with 1-3 halogens; and x is 0, 1, or 2.