Oligonucleotides comprising a ligand tethered to a modified or non-natural nucleobase
View Patent ↗One aspect of the present invention relates to a double-stranded oligonucleotide comprising at least one ligand tethered to an altered or non-natural nucleobase. In certain embodiments, the non-natural nucleobase is difluorotolyl, nitropyrrolyl, or nitroimidazolyl. In certain embodiments, the ligand is a steroid or aromatic compound. In certain embodiments, only one of the two oligonucleotide strands comprising the double-stranded oligonucleotide contains a ligand tethered to an altered or non-natural nucleobase. In certain embodiments, both of the oligonucleotide strands comprising the double-stranded oligonucleotide independently contain a ligand tethered to an altered or non-natural nucleobase. In certain embodiments, the oligonucleotide strands comprise at least one modified sugar moiety. Another aspect of the present invention relates to a single-stranded oligonucleotide comprising at least one ligand tethered to an altered or non-natural nucleobase. In certain embodiments, the non-natural nucleobase is difluorotolyl, nitropyrrolyl, or nitroimidazolyl. In certain embodiments, the ligand is a steroid or aromatic compound. In certain embodiments, the ribose sugar moiety that occurs naturally in nucleosides is replaced with a hexose sugar, polycyclic heteroalkyl ring, or cyclohexenyl group. In certain embodiments, at least one phosphate linkage in the oligonucleotide has been replaced with a phosphorothioate linkage.
1. A compound represented by formula VII:
wherein:
R 1 is optionally substituted aralkyl, —Si(R 7 ) 3 , —C(O)R 7 , or —C(O)N(R 8 ) 2 ;
R 2 represents independently for each occurrence H, alkyl, or halogen;
R 3 is
R 4 is alkyl, aralkyl, —Si(R 7 ) 3 , —C(O)R 7 , or —C(O)N(R 8 ) 2 ;
R 5 is halogen;
R 6 is alkyl;
R 7 and R 9 represent independently for each occurrence alkyl, aryl, or aralkyl;
R 8 represents independently for each occurrence H, alkyl, aryl, or aralkyl;
R 10 represents independently for each occurrence H or alkyl;
R 11 represents independently for each occurrence H, alkyl, or halogen;
x is 1, 2, or 3;
y is 1 or 2; and
m is 1, 2, 3, 4, 5, or 6;
and sterioisomers thereof.
2. The compound of claim 1 , wherein R 1 is an optionally substituted trityl.
3. The compound of claim 1 , wherein R 1 is
4. The compound of claim 1 , wherein R 5 is fluoride.
5. The compound of claim 1 , wherein R 3 is
and the solid support is controlled pore glass.
6. The compound of claim 1 , wherein compound VII is represented by
7. The compound of claim 1 , wherein compound VII is represented by
wherein
is a solid support.
8. An oligonucleotide prepared from a compound of claim 1 .
9. The oligonucleotide of claim 8 , wherein the oligonucleotide is a single-stranded oligonucleotide.
10. The oligonucleotide of claim 9 , wherein the single-stranded oligonucleotide is a single-stranded siRNA.
11. The oligonucleotide of claim 9 , wherein the single-stranded oligonucleotide is a microRNA.
12. The oligonucleotide of claim 8 , wherein the oligonucleotide is a double-stranded oligonucleotide.
13. The oligonucleotide of claim 12 , wherein the double-stranded oligonucleotide is a double-stranded siRNA.