Nucleotide and oligonucleotide prodrugs

A pronucleotide of formula (I):

• or the racemates, enantiomers, diastereomers, geometric isomers, tautomers thereof,
• wherein
• X=absent, O, NH, NR, S;
• X1=absent, O, NH;
• A=absent, aryl, aralkyl;
• n=0, 1, 2, 3, 4, 5;
• R=alkyl, cycloalkyl, aryl, aralkyl, heterocylic, O-alkyl, O-heteroaryl, or steroidal;
• R1 is H, OH, O-alkyl, alkyl, cycloalkyl, aryl, aralkyl, heterocyclic, O-aryl, O-heteroarylaryl, heterocyclic;
• R2 is O-alkyl, alkyl, cycloalkyl, aryl, aralkyl, heterocyclic, O-aryl, or O-heteroarylaryl;
• R3 is selected from hydrogen, alkyl, C(O)-alkyl, C(O)O-alkyl, C(O)-aryl, C(O)O-aryl, C(O)NH-alkyl, and C(O)NH-aryl;
• Y, Z are independently, O and S;
• B1, B2 are independently adenine, guanine, thymine, cytosine, uracil or modified nucleobases;
• and
• m=1 to 40;
• wherein said alkyl as appear in R, R1, R2, and R3, each independently, is further optionally substituted by one or more moieties selected from the group consisting of —F, —Cl, —Br, —I, —OH, protected hydroxyl, —CN, —NO2, amino, protected amino, —NH—C1-C12-alkyl, —NH—C2-C12-alkenyl, —NH—C3-C12-cycloalkyl, —NH-aryl, —NH-heteroaryl, —NH-heterocycloalkyl, -dialkylamino, -diarylamino, -diheteroarylamino, —O—C1-C12-alkyl, —O—C2-C12-alkenyl, —O—C3-C12-cycloalkyl, —O-aryl, —O-heteroaryl, —O-heterocycloalkyl, —-C(O)—C1-C12-alkyl, —C(O)—C2-C12-alkenyl, —C(O)—C3-C12-cycloalkyl, —C(O)-aryl, —C(O)-heteroaryl, —C(O)-heterocycloalkyl, —CONH2, —CONH—C1-C12-alkyl, —CONH-alkenyl, —CONH—C3-C12-cycloalkyl, —CONH-aryl, —CONH-heteroaryl, —CONH-heterocycloalkyl, —OCO2—C1-C12-alkyl, —OCO2—C2-C12-alkenyl, —OCO2—C3-C12-cycloalkyl, —OCO2-aryl, —OCO2-heteroaryl, —OCO2-heterocycloalkyl, —OCONH2, —OCONH—C1-C12-alkyl, —OCONH—C2-C12-alkenyl, —OCONH—C3-C12-cycloalkyl, —OCONH-aryl, —OCONH-heteroaryl, —OCONH-heterocycloalkyl, —NHC(O)—C1-C12-alkyl, —NHC(O)—C2-C12-alkenyl, —NHC(O)—C3-C12-cycloalkyl, —NHC(O)-aryl, —NHC(O)-heteroaryl, —NHC(O)-heterocycloalkyl, —NHCO2—C1-C12-alkyl, —NHCO2—C2-C12-alkenyl, —NHCO2—C3-C12-cycloalkyl, —NHCO2-aryl, —NHCO2-heteroaryl, —NHCO2-heterocycloalkyl, —NHC(O)NH2, —NHC(O)NH—C1-C12-alkyl, —NHC(O)NH—C2-C12-alkenyl, —NHC(O)NH—C3-C12-cycloalkyl, —NHC(O)NH-aryl, —NHC(O)NH-heteroaryl, —NHC(O)NH-heterocycloalkyl, —NHC(S)NH2, —NHC(S)NH—C1-C12-alkyl, —NHC(S)NH—C2-C12alkenyl, —NHC(S)NH—C3-C12-cycloalkyl, —NHC(S)NH-aryl, —NHC(S)NH-heteroaryl, —NHC(S)NH-heterocycloalkyl, —NHC(NH)NH2, —NHC(NH)NH—C1-C12-alkyl, —NHC(NH)NH—C2-C12-alkenyl, —NHC(NH)NH—C3-C12-cycloalkyl, —NHC(NH)NH-aryl, —NHC(NH)NH-heteroaryl, —NHC(NH)NH-heterocycloalkyl, —NHC(NH)—C1-C12-alkyl, —NHC(NH)—C2-C12-alkenyl, —NHC(NH)—C3-C12-cycloalkyl, —NHC(NH)-aryl, —NHC(NH)-heteroaryl, —NHC(NH)-heterocycloalkyl, —C(NH)NH—C1-C12-alkyl, —C(NH)NH—C2-C12-alkenyl, —C(NH)NH—C3-C12-cycloalkyl, —C(NH)NH-aryl, —C(NH)NH-heteroaryl, —C(NH)NH-heterocycloalkyl, —S(O)—C1-C12-alkyl, —S(O)—C2-C12-alkenyl, —S(O)—C3-C12-cycloalkyl, —S(O)-aryl, —S(O)-heteroaryl, —S(O)-heterocycloalkyl, —SO2NH2, —SO2NH—C1-C12-alkyl, —SO2NH—C2-C12-alkenyl, —SO2NHC3-C12-cycloalkyl, —SO2NH-aryl, —SO2NH-heteroaryl, —SO2NH-heterocycloalkyl, —NHSO2—C1-C12-alkyl, —NHSO2—C2-C12-alkenyl, —NHSO2—C3-C12-cycloalkyl, —NHSO2-aryl, —NHSO2-heteroaryl, —NHSO2-heterocycloalkyl, —CH2NH2, —CH2SO2CH3, -aryl, -arylalkyl, -heteroaryl, -heteroarylalkyl, -heterocycloalkyl, —C3-C12-cycloalkyl, polyalkoxyalkyl, polyalkoxy, -methoxymethoxy, -methoxyethoxy, —SH, —S—C1-C12-alkyl, —S—C2-C12-alkenyl, —S—C3-C12-cycloalkyl, —S-aryl, —S-heteroaryl, —S-heterocycloalkyl, and methylthiomethyl.