A compound of formula (1) or a pharmaceutically acceptable salt thereof, where X2 is selected from the group consisting of N and CR2； X3 is selected from the group consisting of N and CR3； X4 is selected from the group consisting of N and CR4； provided that only one of X2, X3, and X4 is N； R1 is selected from the group consisting of hydrogen or methyl； R2, R3, R4, R5, R6, and R7 are hydrogen； L is -NHC (O) NH-； R12, R13, and R14 are independently selected from the group consisting of hydrogen, alkoxy, alkyl, haloalkyl, and halogen, with the proviso that the term "alkyl" as used herein means a linear chain hydrocarbon. or branched containing from 1 to 10 carbon atoms, the term "alkoxy" as used herein, means an alkyl group, as defined herein, anchored to the molecular origin radical through an oxygen atom, the term "haloalkyl" as used herein, means less a halogen, as defined herein, anchored to the molecular radical of origin through an alkyl group, as defined herein, the term "halo" or "halogen" as used herein, means - Cl, -Br, -I or -F.Un compuesto de fórmula (1)o una sal farmacéuticamente aceptable del mismo, dondeX2 se selecciona del grupo que consiste en N y CR2；X3 10 se selecciona del grupo que consiste en N y CR3；X4 se selecciona del grupo que consiste en N y CR4；siempre que solo uno de X2, X3, y X4 es N；R1 se selecciona del grupo que consiste en hidrógeno o metilo；R2, R3, R4, R5, R6, y R7 son hidrógeno；L es -NHC(O)NH-；R12, R13, y R14 se seleccionan independientemente del grupo que consiste en hidrógeno, alcoxi, alquilo, haloalquilo, yhalógeno；con la condición de queel término "alquilo" según se utiliza en la presente memoria, significa un hidrocarburo de cadena lineal o ramificadaque contiene de 1 a 10 átomos de carbono,el término "alcoxi" según se utiliza en la presente memoria, significa un grupo alquilo, según se define en la presentememoria, anclado al radical molecular de origen a través de un átomo de oxígeno,el término "haloalquilo" según se utiliza en
