A compound of Formula I or an enantiomer, a diastereomer, a racemate, a tautomer, salt or hydrate thereof, wherein A is selected from the group consisting of: R 2 is a halogen atom; each of R 3 and R 4 is, independently, hydrogen or an aliphatic group; and each of R 5 and R 6 is, independently, a hydrogen, -OH, alkoxy, halide, trifluoroalkyl, alpha-haloalkyl, trifluoroalkoxy, or an optionally substituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl or aralkyl, or a heteroaromatic moiety; wherein X 1 is selected from the group consisting of -O-, -NH-, and -S-; wherein B is an unsubstituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, or heteroaromatic group or is an aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, or heteroaromatic group substituted with one or more X 2, each X 2 being independently selected from the group consisting of hydrogen, halogen, hydroxyl, alkoxyl, -CN; an optionally substituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, heteroaromatic moiety; -OR R, -S(=O) n R d, -NR b R c, -C(=O)R a and -C(=O)OR a; wherein n is 0-2, R a, for each occurrence, is independently selected from the group consisting of hydrogen and an optionally substituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, or a heteroaromatic moiety; R b and R c, for each occurrence, are independently selected from the group consisting of hydrogen; hydroxy; SO 2 R d; and aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, heteroaromatic or an acyl moiety; R d, for each occurrence, is independently selected from the group consisting of hydrogen; -N(R e) 2; aliphatic, aryl and heteroaryl; R e, for each occurrence, is independently hydrogen or aliphatic; and R R is an optionally substituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, heteroaromatic or acyl moiety; and wherein D is phosphate ester or phosphite ester; or a compound having the structure for use in the treatment of the human or animal body by therapy. R 2 is a halogen atom; each of R 3 and R 4 is, independently, hydrogen or an aliphatic group; and each of R 5 and R 6 is, independently, a hydrogen, -OH, alkoxy, halide, trifluoroalkyl, alpha-haloalkyl, trifluoroalkoxy, or an optionally substituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl or aralkyl, or a heteroaromatic moiety; wherein X 1 is selected from the group consisting of -O-, -NH-, and -S-; wherein B is an unsubstituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, or heteroaromatic group or is an aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, or heteroaromatic group substituted with one or more X 2, each X 2 being independently selected from the group consisting of hydrogen, halogen, hydroxyl, alkoxyl, -CN; an optionally substituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, heteroaromatic moiety; -OR R, -S(=O) n R d, -NR b R c, -C(=O)R a and -C(=O)OR a; wherein n is 0-2, R a, for each occurrence, is independently selected from the group consisting of hydrogen and an optionally substituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, or a heteroaromatic moiety; R b and R c, for each occurrence, are independently selected from the group consisting of hydrogen; hydroxy; SO 2 R d; and aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, heteroaromatic or an acyl moiety; R d, for each occurrence, is independently selected from the group consisting of hydrogen; -N(R e) 2; aliphatic, aryl and heteroaryl; R e, for each occurrence, is independently hydrogen or aliphatic; and R R is an optionally substituted aliphatic, alicyclic, heteroaliphatic, heterocyclic, aryl, aralkyl, heteroaromatic or acyl moiety; and wherein D is phosphate ester or phosphite ester; or a compound having the structure for use in the treatment of the human or animal body by therapy.