Phosphoramidate Isomer Separation via Crystallization
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Solution Overview
Problem
Current methods fail to efficiently isolate high-purity single isomers of phosphoramidate nucleoside prodrugs like NUC-1031 due to their similar structural and polar characteristics, making it difficult to balance purity and yield in the purification process.
Innovation Solution
A method involving reacting compound 61501h with 61501g under alkaline conditions, followed by reacting with 61501f, and then isolating compound 61501b through isomer separation in ethyl acetate and petroleum ether, achieving a crystalline form with specific X-ray powder diffraction patterns, resulting in a purity of at least 90%, 95%, or 99%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation methods such as chiral column or column chromatography are used, then isomer separation is achieved, but the purity and yield cannot be balanced simultaneously
Solution Approach 1:
The patent changes the physical-chemical parameters of the system by selecting specific solvents (ethyl acetate and petroleum ether) with particular polarity and boiling point characteristics. This parameter change enables the enantiomers to exhibit different solubilities and crystallization behaviors, allowing high-purity separation (99% ee) while maintaining acceptable yield through controlled crystallization conditions rather than conventional chromatographic methods
Solution Approach 2:
The patent utilizes phase transition (crystallization) as the separation mechanism. By controlling the phase transition from dissolved state to crystalline state through temperature change and solvent removal, the enantiomers are separated based on their different crystal lattice formation tendencies. The racemic mixture undergoes phase transition to yield enriched crystalline form of one enantiomer, achieving both high purity and reasonable yield simultaneously
2Manufacturing precision
If purification via silica gel column is used, then isomer separation is achieved, but the purity reaches only 48% and 52% respectively
Solution Approach 1:
The patent extracts the enantiomers from the racemic mixture through selective crystallization rather than adsorption on silica gel. By taking out the target enantiomer in crystalline form through controlled solvent addition and temperature adjustment, the method achieves much higher purity (99% ee) compared to column chromatography, while also improving ease of manufacture as crystallization is simpler and more scalable than column purification
Solution Approach 2:
The patent introduces ethyl acetate and petroleum ether as intermediary substances that mediate the separation process. These solvents act as intermediaries that create a selective environment where one enantiomer preferentially crystallizes while the other remains in solution. The intermediary solvents enable the separation to proceed with high purity and efficiency without requiring complex chromatographic media like silica gel
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
The method provides high-purity compound 61501b, enhancing the production efficiency and quality of phosphoramidate nucleoside prodrugs, improving their biological activity and reducing toxic side effects, while meeting industrial production demands.
Implementation Method 1
adding petroleum ether dropwise to the above solution system, and crystallizing, thereby giving the compound 61501b
Implementation Method 2
Obtaining the composition enriched in the crystalline form of compound 61501b by isomer separation of the compound 61502
Implementation Method 3
an X-ray powder diffraction pattern of the crystalline form of compound 61501b has peaks at the following 2θ angles: 7.2° ± 0.3°, 9.6° ± 0.3° and 23.1° ± 0.3°
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present disclosure involves a composition enriched in compound 61501b, wherein the compound 61501b has a purity of not less than 90% or more. The composition has a significant advantage in preparing a high-purity compound Sp-1. In addition, the present disclosure also provides a preparation method of the composition enriched in compound 61501b. The method adopts a crystallization technique to perform separation and purification, has a simple and convenient operation and good reproducibility, and therefore the compound 61501b in the prepared composition has high purity and quality. Further, the present disclosure also involves a novel crystal form of compound 61501b.