A compound of formula (I) ** Formula ** in which: A1 is N and A2 is CR6, R1 is a group of formula (II), ** Formula ** R2 is halogen； cycloalkyl； or C1-6 alkyl or -O-C1-6 alkyl, which may be substituted with a substituent selected from -OH, -O-C1-6 alkyl, -NH2, -NH-C1-6 alkyl, -N (C1 alkyl -6) 2, and a nitrogen-containing monocyclic hetero ring which may be substituted with C1-6 alkyl, R3 is C1-6 alkyl, cycloalkyl, cycloalkenyl, aryl, heteroaryl or a saturated hetero ring, each of which may be substituted with halogen, C1-6 alkyl, cycloalkyl, -OH, oxo, -O-C1-6 alkyl, -COOH, -CO-O-C1-6 alkyl, -CO-O-C1-6-alkyl-C1-alkyl 6, -CO-O-C1-6-aryl alkylene, -CO-O-C1-6-O-aryl alkylene, -CO-NH2, -CO-NH-C1-6 alkyl, -CO-N (C1 alkyl -6) 2, -CO-N (C1-6 alkyl) -aryl, -CO-N (C1-6 alkyl) - (C1-6-aryl alkyl), -CO-NH-C1-6-OH alkylene, -CO-NH-C1-6-CO2H alkylene or a sulfur-containing monocyclic saturated hetero ring, R4 and R5 are the same or different, and each is hydrogen or C1-6 alkyl, R6 is hydrogen or C1-6 alkyl, and Ra and Rb are combined with the adjacent nitrogen atom to forming a polycyclic nitrogen-containing hetero ring which may be substituted with: halogen； -OH； oxo； -O-C 1-6 alkyl； cyano； nitro； halogen-C1-6 alkyl； cycloalkyl； aryl that may be substituted with a group selected from a group G1； a hetero ring that may be substituted with a group selected from a group G2； C1-6- alkylene (aryl which may be substituted with a group selected from a group G1)； C1-6-SO2-NR7R8 alkylene； C1-6-heteroaryl alkylene； C1-6 alkyl which may be further substituted with -OH, -O-C1-6 alkyl, cyano, or cycloalkyl； -COOH； -CO-O-C1-6 alkyl, -CO-O-C1-6 alkyl-O-C1-6 alkyl, -CO-O- C1-6-aryl alkylene, -CO-O-C1-6-O alkylene -aryl, -CO-NH2, -CONH- C1-6 alkyl, -CO-N (C1-6 alkyl) 2, -CO-N (C1-6 alkyl) -aryl, -CO-N (C1-6 alkyl ) - (C1-6-aryl alkylene), -CONH- C1-6-OH alkylene, -CO-NH-C1-6-CO2H alkylene； -NHSO2-R9； -SO2-NR7R8； or a monocyclic hetero ring containing nitrogen； wherein R7 and R8 are the same or d
