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