Patent ID: 8093385

Claim:
A compound of formula (I): wherein: R 1 and R 2 , independently of each other, are halogen, benzo[1,3]dioxole, unsubstituted or mono- or bi-substituted with halogen, 2,3-dihydro-benzo[1,4]dioxine, unsubstituted or mono- or bi-substituted with halogen, 3,4-dihydro-2H-benzo[b][1,4]dioxepine, unsubstituted or mono- or bi-substituted with halogen monocyclic 5- or 6-membered aryl or monocyclic 5- or 6-membered heteroaryl, unsubstituted or substituted with one to four substituents selected from the group consisting of halogen, lower alkyl, haloloweralkyl, carboxy, alkoxy, hydroxy, aminoloweralkyl and —OCF 3 ; bicyclic 8- to 12-membered heteroaryl, unsubstituted or substituted with one to four substituents selected from the group consisting of halogen, lower alkyl, haloloweralkyl, carboxy, alkoxy, hydroxy, aminoloweralkyl and —OCF 3 ; X is O, C, S, or N, unsubstituted or substituted with lower alkyl; and a is a single bond or an alkynyl bond, and pharmaceutically acceptable salts thereof.