A compound according to Formula Ia: or one of its pharmaceutically acceptable salts or one of its stereoisomers, in which: Ar1 is aryl, which may be optionally substituted with one or more functional groups selected from the group consisting of halogen, haloalkyl, cyano , alkyl, alkoxy and haloalkoxy； Ar2 is aryl, which may be optionally substituted with one or more functional groups selected from the group consisting of halogen, haloalkyl, cyano, alkyl, alkoxy and haloalkoxy； R1 is alkyl, in which the alkyl group is substituted with either a -OR4 group or a -NR5R6 group； R2 is selected from the group consisting of aryl and heteroaryl, in which the aryl and heteroaryl can each be optionally substituted with one or more functional groups selected from the group consisting of halogen, alkyl, haloalkyl, cyano, cycloalkyl and alkoxy； R4 is selected from the group consisting of hydrogen, alkyl, haloalkyl and phosphates； R5 and R6 are each independently selected from the group consisting of hydrogen and alkyl, wherein the alkyl may be optionally substituted with one or more halogens； or R5 and R6 are taken together with the nitrogen to which they are attached to form a heterocyclyl ring that forms 4, 5, 6 or 7 member rings.Un compuesto según la Fórmula Ia: o una de sus sales farmacéuticamente aceptables o uno de sus estereoisómeros, en la que: Ar1 es arilo, que puede estar opcionalmente sustituido con uno o más grupos funcionales seleccionados del grupo que consiste en halógeno, haloalquilo, ciano, alquilo, alcoxilo y haloalcoxilo； Ar2 es arilo, que puede estar opcionalmente sustituido con uno o más grupos funcionales seleccionados del grupo que consiste en halógeno, haloalquilo, ciano, alquilo, alcoxilo y haloalcoxilo； R1 es alquilo, en el que el grupo alquilo está sustituido bien con un grupo -OR4 o un grupo -NR5R6； R2 se selecciona del grupo que consiste en arilo y heteroarilo, en el que el arilo y el heteroarilo pueden estar cada uno sustituido opcionalmente con uno o
