A compound of formula (I): ** Formula ** wherein R1 is an optionally substituted group selected from C3-C7 cycloalkyl, heterocyclyl, aryl and heteroaryl； R2 is hydrogen, COR4 or an optionally substituted group selected from linear or branched C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C7 cycloalkyl, heterocyclyl, aryl and heteroaryl； R3 is hydrogen, halogen, cyano, nitro, NHCOR4, COR4, NR5R6, NR5COR4, OR7, SR7, SOR10, SO2R10, NHSOR10, NHSO2R10, or an optionally substituted group selected from linear or branched C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C7 cycloalkyl, heterocyclyl, aryl, heteroaryl, R8R9NC1-C6 alkyl and R8O-C1-C6 alkyl； R4 is hydrogen, NR5R7, OR7, SR7, or an optionally substituted group selected from linear or branched C1-C6 alkyl, C3-C7 cycloalkyl, heterocyclyl, aryl, heteroaryl, R8R9N-C1-C6 alkyl and R8O-C1-C6 alkyl； R5 and R6 are independently hydrogen, or an optionally substituted group selected from linear or branched C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C7 cycloalkyl, heterocyclyl, aryl, heteroaryl, R8R9N-C1-C6 alkyl and R8O-C1-C6 alkyl, or R5 and R6 taken together with the nitrogen to which they are attached, form an optionally substituted heterocyclyl group； R7 is hydrogen, COR5, SOR10, SO2R10 or an optionally substituted group selected from linear or branched C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C7 cycloalkyl, heterocyclyl, aryl, heteroaryl, R8R9N-C1-C6 alkyl , R8O-C1-C6 alkyl, heterocyclyl-C1-C6 alkyl, aryl-C1-C6 alkyl and heteroaryl-C1-C6 alkyl, where R5 is as defined above； R8 and R9 are independently hydrogen, COR4 or an optionally substituted group selected from linear or branched C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C7 cycloalkyl, heterocyclyl, aryl and heteroaryl, or R8 and R9, taken together with the nitrogen to which they are attached, they form an optionally substituted heterocyclyl group, where R 4 is as defined above； R10 is hydrogen, NR5R6, OR7 or an optionally substituted group selected from li
