Imidazopirrolidinona refers to compounds of formula (i) where a is a compound of formula (i), (ii), among others, where R1 is Methyl or Halo R8 is H, Methyl, Ethyl, among others b is a compound of formula (a), (b), in others, where R2 is chlorine, Fluorine, CN, among others R 7 Halo is H or alkyl (c1-c4) optionally substituted by alkoxyl (c1-c4) R3 is isopropyl,Ciclopropilo, Isobutyl, among others R4 is a compound of formula (X), (and), among others, where R15 is H, OCH3, CH2CH3, among others R16 is H, Halo, CN, among others R5 is H, alkyl (c1-c4), CN, among others.Preferred compounds are: 5 - (2 - methyl - 5 - chloro phenyl) - 6 - (4 - methyl - 2 - chloro phenyl) - 2 - (5 - fluoro - 2 - methoxy phenyl) - 1 - 4 - isopropyl - oxo - 5.6 - dihydro 1h pyrrolo [3,4 - d] imidazole - 4 - One 5 - (2 - methyl - 5 - chloro phenyl) - 6 - (4 - chlorine - 2 - methyl - 1 - isopropyl phenyl) - 2 - (trifluoromethoxy) - phenyl) - 5.6 - dihydro 1h pyrrolo [3,4-d] imidazole - 4 - One among others. It also relates to a Pharmaceutical composition.These compounds are inhibitors of the interaction between p53 and MDM2 or mdm4 being useful in the treatment of cancerSE REFIERE A COMPUESTOS DERIVADOS DE IMIDAZOPIRROLIDINONA DE FORMULA (I) DONDE A ES UN COMPUESTO DE FORMULA (i), (ii), ENTRE OTROS, EN DONDE R1 ES HALO O METILO R8 ES H, METILO, ETILO, ENTRE OTROS B ES UN COMPUESTO DE FORMULA (a), (b), ENTRE OTROS, EN DONDE R2 ES CLORO, FLUORO, CN, ENTRE OTROS R7 ES H, HALO O ALQUILO(C1-C4) OPCIONALMENTE SUSTITUIDO CON ALCOXILO(C1-C4) R3 ES ISOPROPILO, CICLOPROPILO, ISOBUTILO, ENTRE OTROS R4 ES UN COMPUESTO DE FORMULA (x), (y), ENTRE OTROS, EN DONDE R15 ES H, OCH3, CH2CH3, ENTRE OTROS R16 ES H, HALO, CN, ENTRE OTROS R5 ES H, ALQUILO(C1-C4), CN, ENTRE OTROS. SON COMPUESTOS PREFERIDOS: 5-(5-CLORO-2-METIL-FENIL)-6-(4-CLORO-2-METIL-FENIL)-2-(5-FLUORO-2-METOXI-FENIL)-1-ISOPROPIL-4-OXO-5,6-DIHIDRO-1H-PIRROLO[3,4-d]IMIDAZOL-4-ONA 5-(5-CLORO-2-METIL-FENIL)-6-(4-CLORO-2-METIL-FENIL)-1-ISOPROPIL-2-(2-TRIF
