Isoxazole derivatives which are represented by the formula (I) in which R 1 represents hydrogen, lower alkyl, amino, lower alkylamino, di-lower alkylamino, phenyl lower alkylamino, acylamino, halogen, lower alkoxy, lower alkylthio or lower alkylsulfinyl, R2 represents aryl or unsubstituted heteroaryl, or aryl or heteroaryl which is substituted with 1-3 substituents selected from halogen, lower alkyl, lower alkoxy, lower haloalkyl, lower alkylenedioxy and benzyloxy, R3 represents hydrogen or lower alkyl, R4 represents substituted or non-substituted phenyl substituted, or substituted or unsubstituted heterocyclic group, and y represents - (CH2) n-, -CO-, -CH (CH3) -, -O-, -NH-, where n is an integer value 0-3, or pharmaceutically acceptable salts thereof, where the term "lower" means that groups with this prefix each have a number of carbons not greater than 6.Derivados de isoxazol que están representados por la fórmula (I) en la que R1 representa hidrógeno, alquilo inferior, amino, alquilamino inferior, di-alquilamino inferior, fenil alquilamino inferior, acilamino, halógeno, alcoxi inferior, alquiltio inferior o alquilsulfinilo inferior, R2 representa arilo o heteroarilo no sustituido, o arilo o heteroarilo que está sustituido con 1-3 sustituyentes seleccionados de halógeno, alquilo inferior, alcoxi inferior, haloalquilo inferior, alquilenodioxi inferior y benciloxi, R3 representa hidrógeno o alquilo inferior, R4 representa fenilo sustituido o no sustituido, o grupo heterocíclico sustituido o no sustituido, e y representa - (CH2) n-, -CO-, -CH (CH3) -, -O-, -NH-, siendo n un número entero de valor 0-3, o sales farmacéuticamente aceptables de los mismos, donde el término "inferior" significa que los grupos con este prefijo poseen cada uno un número de carbonos no mayor que 6.
