Trialkyne linking agents and methods of use
Described are improved linking agents that are useful for facilitating the attachment of targeting groups, pharmacokinetic (PK) enhancers or modifiers, or other delivery agents to oligonucleotides. The described linking agents may exhibit improved reaction yields, stability, and biological activity, particularly when used in connection with oligonucleotide-based compounds, such as RNA interference (RNAi) agents.
1. A compound of Formula III,
or a pharmaceutically acceptable salt thereof,
wherein,
L 1 , L 2 , and L 3 are each linkers of the formula:
L 4 is selected from the group consisting of:
wherein indicates the point of attachment;
R 4 is H or optionally substituted alkyl;
X is O or S; and
RNA comprises or consists of an RNAi agent.
2. The compound or pharmaceutically acceptable salt thereof of claim 1 , wherein X is O.
3. The compound or pharmaceutically acceptable salt thereof of claim 1 , wherein X is S.
4. The compound or pharmaceutically acceptable salt thereof of claim 1 , wherein L 1 , L 2 , and L 3 are each
5. The compound or pharmaceutically acceptable salt thereof of claim 1 , wherein L 1 , L 2 , and L 3 are each
6. The compound or pharmaceutically acceptable salt thereof of claim 1 , wherein the compound is selected from the group consisting of:
Compound
No.
Structure
1-O-III
1-S-III
2-O-III
2-S-III
3-O-III
3-S-III
4-O-III
4-S-III
5-O-III
5-S-III
6-O-III
6-S-III
7-O-III
7-S-III
8-O-III
8-S-III
9-O-III
9-S-III
10-O-III
10-S-III
11-O-III
11-S-III
12-O-III
12-S-III
13-O-III
13-S-III
14-O-III
14-S-III
or a pharmaceutically acceptable salt thereof, wherein RNA comprises or consists of an RNAi agent.
7. The compound or pharmaceutically acceptable salt thereof of claim 1 , wherein L 4 is of the formula:
8. A method of reacting a compound of Formula III
with a targeting ligand (TL) comprising an azide to form a compound of Formula V
wherein,
L 1 , L 2 , and L 3 are each linkers of the formula:
L 4 is selected from the group consisting of:
wherein indicates the point of attachment;
R 4 is H or optionally substituted alkyl;
TL is a targeting ligand;
X is O or S;
Y is O or S; and
RNA comprises or consists of an RNAi agent.
9. The method of claim 8 , wherein Y is O.
10. The method of claim 8 , wherein Y is S.
11. The method of claim 8 , wherein L 1 , L 2 , and L 3 are each
12. The method of claim 8 , wherein L 1 , L 2 , and L 3 are each
13. The method of claim 8 , wherein L 4 is of the formula:
14. A method of reacting a compound of Formula II:
with an RNAi agent to form a compound of Formula III:
wherein,
L 1 , L 2 , and L 3 are each linkers of the formula of the formula:
L 4 is selected from the group consisting of:
wherein indicates the point of attachment;
each instance of R 1 is optionally substituted alkyl;
R 2 is optionally substituted alkyl; and
R 4 is H or optionally substituted alkyl
X is O or S; and
RNA comprises or consists of an RNAi agent.
15. The method of claim 14 , wherein X is O.
16. The method of claim 14 , wherein X is S.
17. The method of claim 14 , wherein L 1 , L 2 , and L 3 are each
18. The method of claim 14 , wherein L 1 , L 2 , and L 3 are each
19. The method of claim 14 , wherein L 4 is of the formula: