A compound of formula (Ia): ** Formula ** in which: R1, R4 and R5 are each independently selected from the group consisting of hydrogen, - C (O) N (R6) R7 and C (>； = NR6 ) N (R6) R7； R2 is a heteroaryl selected from the group consisting of benzoxazolyl, isoquinolinyl, pyrimidinyl, 4,5-dihydro-1H-benzo [b] azepin-2 (3H) -onyl, 6,7,8,9-tetrahydro-5H- pyrido [3,2-d] azepinyl, 5,6,7,8-tetrahydro-1,6-naphthyridinyl, 5,6,7,8-tetrahydroquinolinyl, 1H-pyrrolo [2,3-b] pyridinyl, benzo [ b] thiophenyl, 7 ', 8'-dihydro-5'Hespiro [[1,3] dioxolane-2,6'-quinoline] -3'-yl, 4b, 5,6,7,7a, 8-hexahydropentalene [ 2,1-b] pyridinyl and 6,7,8,9-tetrahydrocyclohepta [b] pyridinyl, each optionally substituted with one or more substituents, and pyridinyl, substituted with one or more substituents, wherein the substituent is selected from the group consisting of oxo, thioxo, cyano, nitro, halo, haloalkyl, alkyl, optionally substituted cycloalkyl, optionally substituted cycloalkylalkyl, optionally substituted heterocyclyl, optionally substituted heterocyclyl alkyl, optionally substituted heterocyclylalkenyl, optionally substituted heteroaryl optionally substituted, optionally substituted heteroarylalkenyl, -R9-OR8, -R9-O-R10-OR8, -R9-O-R10-OR10- OR8, -R9-O-R10-CN, -R9-O-R10-C ( O) OR8, -R9-OR10-C (O) N (R6) R7, -R9-O-R10-S (O) pR8 (where p is 0, 1 or 2), - R9-O-R10-N (R6) R7, -R9-OR10-C (NR11) N (R11) H, -R9-OC (O) -R8, -R9-C (O) R8, -R9-C (O) OR8, -R9 -C (O) N (R6) R7, -R9- C (O) -R10-N (R6) R7, -R9-N (R6) R7, -R9-N (R6) -R10-N (R6) R7, -R9-N (R6) C (O) OR8, -R9-N (R6) C (O) -R10-N (R6) R7, -R9- N (R6) C (O) R8, -R9 -N (R6) S (O) tR8 (where t is 1 or 2), -R9-S (O) tOR8 (where t is 1 or 2), -R9-S (O) pR8 (where p is 0, 1 or 2) and -R9-S (O) tN (R6) R7 (where t is 1 or 2)； R3 is selected from the group consisting of pyrimidinyl, isoquinolinyl, quinazolinyl, phenanthridinyl, thieno [3,2- c] pyrimidinyl, thieno [3,2-d] pyridazinyl, 6,7-dihydro-5H cyclopenta [4,5] thieno [2,3-d] pyrimidinyl an
