Patent ID: 8383642

Claim:
A compound of the formula: or a pharmaceutically acceptable salt thereof; wherein: R 1 is selected from the group consisting of H, F and Cl; R 2 is selected from the group consisting of H, C 1-3 alkyl, CF 3 , OCH 3 , F, and Cl; R 4 and R 4 a are each independently selected from the group consisting of H, OCH 3 , C 1-3 alkyl, CF 3 , and F, wherein at least one selected from the group consisting of R 4 and R 4 a is H; R 5 is H or C≡CCH 3 ; X is selected from the group consisting of —CH(R 3 )CH 2 —, —C(R 3 )═CH—, —N(R 7 )CH 2 —. and —C(O)CH 2 —; R 3 is selected from the group consisting of H and C 1-3 alkyl; and R 2 is selected from the group consisting of H, C 1-3 alkyl, and phenyl.