A compound of Formula I: ** Formula ** in which: Het is an 8, 9 or 10 membered bicyclic heteroaryl in which at least one ring atom is an N and said heteroaryl is unsubstituted or substituted with one or more Ra substituents； wherein each Ra is independently hydroxyl, halo, amino, cyano, nitro, C1-4 alkyl, C1-12 haloalkyl, C1-4 alkoxy or -C1-4 haloalkoxy； X is -CH2-, -CH2CH2- or -CH2O-； one of W and Y is NH and the other is O or NH； Z is O or S； R1 is -NRbRc； guanidino； a 5- or 6-membered monocyclic heteroaryl in which at least one ring atom is an N and said heteroaryl is unsubstituted or is substituted with one or more Rd substituents； or a 3- to 7-membered monocyclic heterocycloalkyl, wherein at least one ring atom is an N, and said heterocycloalkyl is unsubstituted or is substituted with one or more Re substituents； wherein Rb and Rc are each independently H or C1-4 alkyl； each Rd is independently hydroxyl, halo, amino, cyano, nitro, C1-4 alkyl, C1-12 haloalkyl, C1-4 alkoxy or -C1-4 haloalkoxy； and each Re is independently hydroxyl, halo, amino, cyano, nitro, C1-4 alkyl, C1-12 haloalkyl, C1-4 alkoxy, C1-4 haloalkoxy, -C (O) C1-4 alkyl or -CO2C1-4alkyl ； n is 2； R2 is absent or is hydroxy, methoxy, or trifluoromethoxy； and R3 is C1-6 alkyl, C1-6 alkoxy or C3-8 cycloalkoxy, wherein said cycloalkoxy is unsubstituted or is substituted with one or more substituents selected from the group consisting of hydroxyl, halo, amino, cyano, nitro, alkyl C1-4, C1-12 haloalkyl, C1-4 alkoxy and C1-4 haloalkoxy； or a pharmaceutically acceptable salt thereof.Un compuesto de Fórmula I:**Fórmula** en la que: Het es un heteroarilo bicíclico de 8, 9 o 10 miembros en el que al menos un átomo del anillo es un N y dicho heteroarilo no está sustituido o está sustituido con uno o más sustituyentes Ra； en donde cada Ra es independientemente hidroxilo, halo, amino, ciano, nitro, alquilo C1-4, haloalquilo C1-12, alcoxi C1-4 o haloalcoxi -C1-4； X es -CH2-, -CH2CH2- o -CH2O-； uno de W e Y es NH y
