Oligonucleotide analogues
The present invention relates to novel bicyclic and tricyclic nucleoside and nucleotide analogues as well as to oligonucleotides comprising such elements. The nucleotide analogues, LNAs (Locked Nucleoside Analogues), are able to provide valuable improvements to oligonucleotides with respect to affinity and specificity towards complementary RNA and DNA oligomers. The novel type of LNA modified oligonucleotides, as well as the LNAs as such, are useful in a wide range of diagnostic applications as well as therapeutic applications. Among these can be mentioned antisense applications, PCR applications, strand displacement oligomers, as substrates for nucleic acid polymerases, as nucleotide based drugs, etc. The present invention also relates to such applications.
1. A nucleoside analogue (hereinafter termed “LNA”) of the general formula I
wherein X is selected from —O—;
B is selected from hydrogen, hydroxy, optionally substituted C 1-4 -alkoxy, optionally substituted C 1-4 -alkyl, optionally substituted C 1-4 -acyloxy, nucleobases, DNA intercalators, photochemically active groups, thermochemically active groups, chelating groups, reporter groups, and ligands;
P designates the radical position for an internucleoside linkage to a succeeding monomer, or a 5′-terminal group, such internucleoside linkage or 5′-terminal group optionally including the substituent R 5 ;
one of the substituents R 2 , R 2 *, R 3 , and R 3 * is a group P* which designates an internucleoside linkage to a preceding monomer, or a 3′-terminal group;
R 2 * and R 4 * together designate a biradical selected from
—(CR*R*) r —Y—(CR*R*) s —,
—(CR*R*) r —Y—(CR*R*) s —Y—,
—Y—(CR*R*) r+s —Y—,
—Y—(CR*R*) r —Y—(CR*R*) s — or
—(CR*R*) r+s —,
each R* is independently selected from hydrogen, halogen, hydroxy, mercapto, amino, optionally substituted C 1-6 -alkoxy, optionally substituted C 1-6 -alkyl, DNA intercalators, photochemically active groups, thermochemically active groups, chelating groups, reporter groups, and ligands, Y is —O—, —S—, 0 (zero) or —N(R N )— where R N is selected from hydrogen and C 1-4 -alkyl, and each of r and s is 0-4 with the proviso that the sum r+s is 1-4, and provided that when the biradical is —(CR*R*) r -Y—(CR*R*) s -, then Y is —S— or —N(R N )—; and
each of the substituents R 1 *, R 2 , R 3 , R 5 , and R 5 *, which are present and not involved in P, P* or the biradical, is independently selected from hydrogen, optionally substituted C 1-12 -alkyl, optionally substituted C 2-12 -alkenyl, optionally substituted C 2-12 -alkynyl, hydroxy, C 1-12 -alkoxy, C 2-12 -alkenyloxy, carboxy, C 1-12 -alkoxycarbonyl, C 1-12 -alkylcarbonyl, formyl, aryl, aryloxy-carbonyl, aryloxy, arylcarbonyl, heteroaryl, heteroaryloxy-carbonyl, heteroaryloxy, heteroarylcarbonyl, amino, mono- and di(C 1-6 -alkyl)amino, carbamoyl, mono- and di(C 1-6 -alkyl)-aminocarbonyl, amino-C 1-6 -alkyl-aminocarbonyl, mono- and di(C 1-6 -alkyl)amino-C 1-6 -alkylaminocarbonyl, C 1-6 -alkyl-carbonylamino, carbamido, C 1-6 -alkanoyloxy, sulphono, C 1-6 -alkylsulphonyloxy, nitro, azido, sulphanyl, C 1-6 -alkylthio, halogen, DNA intercalators, photochemically active groups, thermochemically active groups, chelating groups, reporter groups, and ligands, where aryl and heteroaryl may be optionally substituted;
and basic salts and acid addition salts thereof.
2. A kit for the isolation, purification, amplification, detection, identification, quantification, or capture of natural or synthetic nucleic acids, the kit comprising a reaction body and one or more LNAs as defined in claim 1 .
3. A nucleic acid compound comprising the nucleoside analogue of claim 1 .
4. A method of preparing an LNA modified oligonucleotide (an oligomer) comprising making the oligonucleotide with the LNA of claim 1 .
5. The method of claim 4 , wherein the LNA modified oligonucleotide comprises normal nucleosides.