Patent ID: 7897766

Claim:
A compound of formula (I) or a pharmaceutically acceptable salt thereof, wherein X 1 is a bond; A is benzofuranyl, benzoxadiazolyl, benzoisoxazole, benzoisothiazole, benzooxazole, 1,3-benzothiazolyl, benzodioxolyl, benzothiophenyl, chromenyl, cinnolinyl, furyl, furopyridine, isoquinolinyl, isobenzofuran, isoxazolyl, isothiazolyl, naphthyridinyl, oxadiazolyl, oxazolyl, oxazolopyridine, pyrazolyl, pyrrolyl, pyridazinyl, pyradinyl, pyrazinyl, pyrimidinyl, quinoxalinyl, quinolinyl, thiazolyl, thienyl, thienopyridine, thiadiazolyl, triazolyl, triazinyl and thienopyridinyl; and R 1 is selected from the group consisting of hydrogen and C 1 -C 6 alkyl.