A compound of formula: or a pharmaceutically acceptable salt thereof; wherein: R1 represents H or OH; R2 represents a linear, branched or cyclic C 1-6 alkyl radical; C 6-10 aryl optionally substituted by one or more substituents selected from a halogen atom, a linear, branched or cyclic C 1-6 alkyl radical, a linear, branched or cyclic C 1-6 alkoxyl radical, a linear, branched or cyclic C 1-6 haloalkyl radical, a linear, branched or cyclic C 1-6 haloalkoxyl radical; a radical C 6-10 heteroaryl optionally substituted by one or more substituents selected from a halogen atom, a linear, branched or cyclic C 1-6 alkyl radical, a linear, branched or cyclic C 1-6 alkoxyl radical, a linear, branched or cyclic or a C 2-5 heterocycle radical, preferably C 4-5 heterocycle, saturated or unsaturated; preferably unsaturated, comprising from 1 to 3 heteroatom(s) selected from the group consisting of O, N and S; Y represents H or a linear, branched or cyclic C 1-6 alkyl radical; or Y taken together with R 2 forms a 5 or 6 membered ring; n is 0, 1, 2, 3 or 4; Ar represents a bicyclic heterocycle of the structure: wherein: R 3 represents H, halogen, -OR 5 or -NR 6 AR 6B; wherein R 5 represents H, linear, branched or cyclic C 1-6 alkyl; and R 6A and R 6B independently represent H, linear, branched or cyclic C 1-6 alkyl or C 6-10 aryl; R 4 is H; linear, branched or cyclic C 1-6 alkyl; or -C(=O)R 7 wherein R 7 is linear, branched or cyclic C 1-6 alkyl; and X is O or S. R1 represents H or OH; R2 represents a linear, branched or cyclic C 1-6 alkyl radical; C 6-10 aryl optionally substituted by one or more substituents selected from a halogen atom, a linear, branched or cyclic C 1-6 alkyl radical, a linear, branched or cyclic C 1-6 alkoxyl radical, a linear, branched or cyclic C 1-6 haloalkyl radical, a linear, branched or cyclic C 1-6 haloalkoxyl radical; a radical C 6-10 heteroaryl optionally substituted by one or more substituents selected from a halogen atom, a linear, branched or cyclic C 1-6 alkyl radical, a linear, branched or cyclic C 1-6 alkoxyl radical, a linear, branched or cyclic or a C 2-5 heterocycle radical, preferably C 4-5 heterocycle, saturated or unsaturated; preferably unsaturated, comprising from 1 to 3 heteroatom(s) selected from the group consisting of O, N and S; Y represents H or a linear, branched or cyclic C 1-6 alkyl radical; or Y taken together with R 2 forms a 5 or 6 membered ring; n is 0, 1, 2, 3 or 4; Ar represents a bicyclic heterocycle of the structure: wherein: R 3 represents H, halogen, -OR 5 or -NR 6 AR 6B; wherein R 5 represents H, linear, branched or cyclic C 1-6 alkyl; and R 6A and R 6B independently represent H, linear, branched or cyclic C 1-6 alkyl or C 6-10 aryl; R 4 is H; linear, branched or cyclic C 1-6 alkyl; or -C(=O)R 7 wherein R 7 is linear, branched or cyclic C 1-6 alkyl; and X is O or S. R 3 represents H, halogen, -OR 5 or -NR 6 AR 6B; wherein R 5 represents H, linear, branched or cyclic C 1-6 alkyl; and R 6A and R 6B independently represent H, linear, branched or cyclic C 1-6 alkyl or C 6-10 aryl; R 4 is H; linear, branched or cyclic C 1-6 alkyl; or -C(=O)R 7 wherein R 7 is linear, branched or cyclic C 1-6 alkyl; and X is O or S.