Tertiary Amine Backbone Phosphoramidites for Nucleic Acid Synthesis
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Solution Overview
Problem
Existing methods for synthesizing phosphoramidites often result in racemic mixtures or unstable oligomers, making it difficult to produce achiral, enantiomerically pure molecules necessary for biological applications, particularly due to the formation of diastereoisomers which can be toxic and hinder medical use.
Innovation Solution
Development of a tertiary amine backbone for phosphoramidites that allows for high-yield, scalable, and cost-effective synthesis of achiral, sequence-specific modifications in nucleic acid strands and oligo(phosphodiester)s, using a DNA synthesizer, with platforms like 2′ and 11′ enabling multiple functionalities and easy attachment of various moieties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If serinol-based phosphoramidites are used for modification, then chemical functionality is introduced into oligonucleotides, but diastereoisomer mixtures are formed that are toxic and cannot be purified
Solution Approach 1:
The patent employs chiral pool synthesis using naturally occurring amino acids (L- or D-isomers) to introduce a single chiral center in a controlled manner. This asymmetric approach ensures that only one diastereoisomer is formed during phosphoramidite coupling, eliminating the toxic mixture problem while maintaining chemical functionality for further modifications.
2Adaptability or versatility
If multiple phosphoramidite monomers are synthesized for versatile functionalization, then chemical diversity increases, but synthesis complexity and cost increase
Solution Approach 1:
The patent develops a universal chiral phosphoramidite platform based on amino acid backbones that can accommodate various functional groups (fluorophores, biotin, crosslinkers, etc.) through modular attachment. This multi-functional design allows a single core structure to serve multiple purposes, reducing the need for synthesizing numerous separate monomers while maintaining chemical diversity.
Solution Approach 2:
The phosphoramidite monomers are designed with segmented structures where the chiral amino acid backbone is separated from the functional payload. This segmentation allows the core chiral structure to be synthesized once and reused, while only the functional payload needs to be attached variations, significantly reducing overall synthesis complexity.
3Productivity
If phosphoramidite synthesis is performed under restrictive chemical conditions, then coupling yield increases, but stability of modified oligomers decreases
Solution Approach 1:
The patent optimizes the phosphoramidite structure with specific protecting groups and backbone modifications that maintain stability under the required oxidative and basic conditions of solid-phase synthesis. By carefully selecting amino acid derivatives and protecting group chemistry, the monomers achieve both high coupling yields and improved oligomer stability after deprotection.
Data Source
AI summary
It is provided an achiral, non-nucleosidic backbone for phosphoramidites that can be inserted with high yields in nucleic acid strands and sequence-controlled oligo(phosphodiester)s through solid phase synthesis (SPS) using a DNA synthesizer. From this backbone, platforms with useful chemical handles were synthesized, further functionalized, transformed into phosphoramidites and attached to nucleic acid strands and sequence-controlled oligo(phosphodiester)s. The backbone is based on a tertiary amine with a 3-6 carbon spacer between the central nitrogen and the two external hydroxyls. The spacer has been optimized to increase coupling yields and stability.