Resonance-Stabilized Phosphate Mimetics for Oligonucleotide Synthesis
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Solution Overview
Problem
Existing methods for producing modified oligonucleotides with stable phosphate mimetics are limited by the instability of phosphoramidites and phosphoric acid thioesters, which complicates the introduction of detectable labels and functional groups directly on the phosphate backbone during oligonucleotide synthesis.
Innovation Solution
A process involving a trivalent phosphorus derivative reacted with an azide containing an electron acceptor, forming a pentavalent phosphorus atom that is resonance-stabilized, allowing for the incorporation of detectable units or functional groups on the oligonucleotide backbone, thereby enhancing stability and simplifying the synthesis of labeled oligonucleotides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phosphoramidites or phosphoric acid thioesters are used to introduce modifications on the phosphate backbone, then detectable labels and functional groups can be introduced, but the instability of these compounds complicates the synthesis and reduces reliability
Solution Approach 1:
The patent changes the chemical structure parameter of the phosphate mimetic by using a pentavalent phosphorus atom with resonance stabilization instead of the conventional trivalent phosphorus in phosphoramidites. This structural parameter change transforms the unstable P-N bond into a stable resonance-delimited system, maintaining versatility for introducing labels while dramatically improving stability and reliability of the oligonucleotide modifications
Solution Approach 2:
The patent introduces an intermediary resonance-stabilized structure that mediates between the need for reactive modifications and the need for stability. The pentavalent phosphorus intermediate with resonance delimitation acts as a stable intermediary that can be introduced during synthesis and then converted to the final stable phosphate mimetic structure, resolving the contradiction between reactivity and stability
2Ease of operation
If conventional phosphoramidite chemistry is used for oligonucleotide synthesis, then the synthesis process is well-established and easy to perform, but modifications on the phosphate backbone require special reagents and postsynthetic labeling which increases device complexity and time
Solution Approach 1:
The patent merges the phosphate modification introduction step with the standard oligonucleotide synthesis cycle by incorporating the resonance-stabilized phosphate mimetic directly into the phosphoramidite monomer structure. This allows the modification to be introduced during the standard coupling cycle without requiring separate postsynthetic labeling steps, thereby reducing device complexity and synthesis time while maintaining ease of operation
Solution Approach 2:
The patent creates a universal phosphate mimetic structure that can serve multiple functions: it provides structural stability, enables introduction of detectable labels, and is compatible with standard oligonucleotide synthesis chemistry. The resonance-stabilized pentavalent phosphorus structure acts as a multi-functional platform that eliminates the need for separate specialized reagents and procedures
3Ease of manufacture
If phosphorothioates are prepared using H-phosphonate strategy, then radiolabeling can be achieved, but the method does not allow direct introduction of detectable labels or functional groups on the phosphate backbone during synthesis
Solution Approach 1:
The patent applies preliminary action by pre-installing the resonance-stabilized phosphate mimetic structure with the detectable label or functional group already attached during the oligonucleotide synthesis process. This preliminary incorporation eliminates the need for subsequent postsynthetic labeling steps, allowing direct introduction of various detectable labels and functional groups while maintaining ease of manufacture through standard synthesis procedures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in stable oligonucleotides that can be used for various applications, including hybridization probes and gene expression inhibition, with improved resistance to hydrolysis and compatibility with oligonucleotide synthesis chemistry.
Implementation Method 1
a trivalent phosphorus derivative of the chemical structure (I) in which E represents a methyl group or a protected hydroxyl group, in which A represents the 5' end of a nucleotide or of a nucleotide chain and in which B represents the 3' end of a nucleotide or of a nucleotide chain is reacted with an azide of the following structure N3-Acc in which Acc is an electron acceptor or an electron acceptor substituted with the residue R
Implementation Method 2
forming a pentavalent phosphorus atom that is resonance-stabilized
Data Source
AI summary
The present invention concerns modified oligonucleotides and processes for their production wherein these oligonucleotides contain at least once the structure P = N - Acc where Ace is an electron acceptor or an electron acceptor substituted with a residue R and R is any organic substituent.