A compound of formula (I) ** Formula ** wherein: R1 is hydrogen, alkyl, morpholinyl, haloalkylamino, alkyloxadiazolyl, hydroxyl, halopyrrolidinyl, azetidinyl, alkylamino, amino, cyanoalkylamino, halophenylalkylamino or cyanocycloalkylamino； R2, R3, R4, R5 and R6 are independently selected from hydrogen, alkyl, haloalkyl, hydroxyalkyl, alkoxy, haloalkyloxy, halogen, hydroxyl, cyanopyrazinyloxy, pyrazolyl, alkylpyrazolyl, imidazolyl, benzoimidazolyl, 6-oxo-6H-pyridazinyl, alkyl 6-oxo-6H-pyridazinyl, piperazinyl, N-alkylpiperazinyl, piperidinyl, difluoropyrrolidinyl, phenylimidazolyl, oxo-pyrrolidinyl, oxo-oxazolidinyl, morpholinyl, oxo-morpholinyl, oxo-pyridinyl, 2-oxo-2Hpirazinilo, difluoropiperidinyl, haloalquilpiperidinilo, piperidinylalkoxy, oxethanyloxy, alkylpyrazolyl, halopyridinyl, alkylpyridinyl, cycloalkyl, cycloalkylalkyl, halophenyl, alkylcarbonylaminocycloalkylalkyl, haloalkylpiperazinyl, alkylamino, alkoxyalkylpiperazin-1,2-cycloalkylpiperazinyl, hexahydropyrrolo] [4,3-a] pyrazin-7-yl, alkylimidazolyl, azetidinyl, cycloalkylpiperazinyl, alkylimidazolyl, alkoxyalkoxy, imidazo [4,5-c] pyridinyl, alkylpiperazini lo, hexahydropyrrolo [1,2-a] pyrazinyl, haloazetidinyl, pyrimidinyl, and alkenyloxy； A1 is -CH2-, carbonyl, -C (O) O- or absent； A2 is nitrogen or CR7； A3 is nitrogen or CR8； A4 is nitrogen or CR9； R7 is hydrogen, alkyl, haloalkyl, halogen, hydroxyl, haloalkylaminocarbonyl； halophenyl alkylaminocarbonyl, phenylcycloalkylaminocarbonyl, haloalkylphenylakylaminocarbonyl, halophenylcycloalkylaminocarbonyl or halophenylcycloalkylakylaminocarbonyl； R8 is hydrogen, alkyl, haloalkyl, halogen, or hydroxyl； or R7 and R8 together with the carbon atom to which they are attached form a cycloalkyl or substituted pyrrolidinyl, said substituted pyrrolidinyl is haloalkyl or formyl N-substituted pyrrolidinyl； R9 is hydrogen, alkyl, haloalkyl, halogen, or nitro； or R8 and R9 together with the carbon atom to which they are attached form a cycloalkyl； or a pharmaceutica
