A compound including a heterocyclic nucleobase attached to a first carbon atom of an optionally substituted five-member saturated or mono-unsaturated heterocyclic group selected from tetrahydrofuranyl, tetrahydrothienyl, dihydrofuranyl and dihydrothienyl and further including a phosphonoalkoxy or phosphonothioalkyl group attached to a second carbon atom of said five-member saturated or mono-unsturated heterocyclic group, said first carbon atom being adjacent to the heteroatom of said five-member saturated or mono-unsturated heterocyclic group, and said second carbon atom being adjacent neither to the heteroatom nor to the first carbon atom of said five-member saturated or mono-unsturated heterocyclic group, said compound being represented by one of the general formulae (II) and (XIX):
- wherein:
- X, X2, X31 X4 and X5 are each each independently selected from the group consisting of oxygen and sulfur,
- B is a natural or non-natural heterocyclic nucleobase,
- R1 and R2 are each independently selected from the group consisting of hydrogen;
- (—PO3R16)m—PO3R17R18;
- alkyl;
- alkenyl;
- alkynyl;
- cycloalkyl;
- cycloalkenyl;
- cycloalkynyl;
- aryl;
- arylalkyl;
- heterocyclic;
- heterocyclic-alkyl;
- acyloxyalkyl;
- acyloxyalkenyl;
- acyloxyalkynyl;
- acyloxyaryl;
- acyloxyarylalkyl;
- acyloxyarylaikenyl;
- acyloxyarylalkynyl;
- dialkylcarbonate;
- alkylarylcarbonate;
- alkylaikenylcarbonate;
- alkylalkynylcarbonate;
- alkenylarylcarbonate;
- alkynyl-arylcarbonate;
- alkenylalkynylcarbonate;
- dialkenylcarbonate;
- dialkynyl-carbonate;
- wherein said alkyl, alkenyl and alkynyl optionally contains one or more heteroatoms in or at the end of the hydrocarbon chain, said heteroatoms being independently selected from the group consisting of oxygen, sulfur and nitrogen;
- R3, R4, R5, R6, R7 and R8 are each independently selected from the group consisting of hydrogen, azido, halogen, cyano, alkyl, alkenyl, alkynyl, SR14 and OR14;
- R14 is selected from hydrogen;
- alkyl;
- alkenyl;
- alkynyl;
- cycloalkyl;
- cycloalkenyl;
- cycloalkynyl;
- aryl;
- heterocyclic;
- arylalkyl;
- heterocyclic-alkyl;
- acyloxyalkyl;
- wherein said alkyl, alkenyl and alkynyl optionally contain one or more heteroatoms in or at the end of the hydrocarbon chain, said heteroatoms being independently selected from the group consisting of oxygen, sulfur and nitrogen;
- R16, R17 and R18 are independently selected from the group consisting of hydrogen;
- alkyl;
- alkenyl;
- alkynyl;
- cycloalkyl;
- cycloalkenyl;
- cycloalkynyl;
- aryl;
- arylalkyl;
- heterocyclic ring;
- heterocyclic ring-alkyl;
- acyloxyalkyl;
- wherein said alkyl, alkenyl and alkynyl optionally contain one or more heteroatoms in or at the end of the hydrocarbon chain, said heteroatoms being independently selected from the group consisting of oxygen, sulfur and nitrogen;
- X4 and R1, or X5 and R2 may together form an amino-acid residue or polypeptide wherein a carboxyl function of said amino-acid residue being at a distance from the amidate nitrogen not further than 5 atoms is esterified;
- X4 and R1 or X5 and R2 may together form a group having the formula —OC(R9)2OC(O)Y(R10)a wherein Y=N or O, a=1 when Y is 0 and a =1 or 2 when Y is N;
- R9 is selected from the group consisting of hydrogen, alkyl, aryl, alkenyl, alkynyl, alkenylaryl, alkynylaryl or alkylaryl, wherein each of said alkyl, alkenyl, alkynyl and aryl groups is optionally substituted with one or more atoms or groups selected from the group consisting of halo, cyano, azido, nitro and OR14;
- R10 is selected from the group consisting of hydrogen, alkyl, aryl, alkenyl, alkynyl, alkenylaryl, alkynylaryl and alkylaryl, wherein each of said alkyl, alkenyl, alkynyl and aryl groups is optionally substituted with one or more atoms or groups selected from the group consisting of halo, cyano, azido, nitro, OR14 and NR11R12;
- R11 and R12 are each independently selected from the group consisting of hydrogen and alkyl, provided that at least one of R11 and R12 is not hydrogen;
- n is an integer representing the number of methylene groups between X2 and P, each of said methylene groups being optionally and independently substituted with one or two substituents selected from the group consisting of halogen, hydroxyl, sulhydryl and C1-4 alkyl, and n being selected from 1, 2, 3, 4, 5 and 6;
- and
- m is 0 or 1,
- including pharmaceutically acceptable salts, solvates, stereoisomers and prodrugs thereof.