Patent ID: 7145009

Claim:
A chemical compound of formula (I): wherein: R 1 to R 3 are independently selected from hydrogen and lower alkyl; X 1 is C—R 4 ; X 2 is C—R 5 ; X 3 is C—R 6 ; X 4 is C—R 7 R 4 , R 5 and R 7 are independently selected from hydrogen, halogen, hydroxy, alkyl, haloalkyl, aryl, alkoxy, aryloxy, alkoyl, aryloyl, alkylthio, arylthio, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, amino, alkylamino, dialkylamino, nitro, cyano, carboalkoxy, carboaryloxy and carboxy; and R 6 is selected from hydrogen, halogen, alkyl, haloalkyl, aryl, aryloxy, alkylthio, arylthio, alkylsulfoxyl, arylsulfoxyl, alkylsulfonyl, arylsulfonyl, amino, alkylamino, dialkylamino and cyano; wherein either at least one of R 5 and R 6 is selected from chlorine, fluorine, haloalkyl and bromine, or R 5 is selected from halogen, haloalkyl and alkylthio, and a pharmaceutically acceptable salt thereof.