Method for the preparation of (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1-6-naphthyridine-3-carbox-amide by racemate separation by means of diastereomeric tartaric acid esters
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Solution Overview
Problem
Existing methods for separating enantiomers of (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1,6-naphthyridine-3-carboxamide are costly, require specialized equipment, and are not efficient on a large scale due to high solvent recovery needs and limited lifespan of expensive chiral phases.
Innovation Solution
The use of chiral substituted tartaric acid esters to form diastereomeric salts with the racemic mixture, allowing for efficient separation of enantiomers through conventional pilot plant equipment, utilizing solvents like ethanol and water, and subsequent treatment with bases to release the desired enantiomer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chromatographic separation using specialized chiral phases is used, then enantiomer separation is achieved, but acquisition costs and operational costs are high
Solution Approach 1:
The patent replaces expensive, limited-life chiral phases with inexpensive, readily available tartaric acid and conventional solvents. The tartaric acid can be used repeatedly without degradation, eliminating the need for frequent replacement of costly chiral phases while maintaining effective enantiomer separation.
Solution Approach 2:
The patent introduces tartaric acid as an intermediary substance that forms diastereomeric salts with the racemic mixture, enabling separation through conventional filtration and crystallization. This intermediary approach avoids the need for expensive specialized chiral phases while achieving the same separation objective.
2Productivity
If simulated moving bed chromatography is used, then continuous separation is achieved, but additional equipment investment and operational complexity increase
Solution Approach 1:
The patent replaces complex mechanical chromatographic systems (SMB, Varicol) with simple chemical processes involving salt formation, filtration, and crystallization. This substitution maintains continuous production capability while eliminating the need for sophisticated equipment and complex operational procedures.
Solution Approach 2:
The process allows the reaction mixture to self-organize into separable diastereomeric salts through controlled crystallization, eliminating the need for complex external separation equipment. The system performs separation automatically through inherent chemical properties rather than requiring sophisticated mechanical intervention.
3Manufacturing precision
If large-scale solvent recovery is performed, then product purification is achieved, but energy consumption increases significantly
Solution Approach 1:
The patent utilizes phase transitions (crystallization and filtration) instead of energy-intensive solvent evaporation and distillation. By controlling temperature and solvent composition to induce crystallization of the desired enantiomer, the process achieves high purity without requiring gigantic falling-film evaporators or huge amounts of energy.
Solution Approach 2:
The patent changes physical parameters (temperature, solvent ratio) to control crystallization and separation, replacing energy-intensive solvent recovery operations. By adjusting these parameters, the process achieves effective purification with minimal energy input compared to traditional high-temperature evaporation methods.
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
Achieves high enantiomeric excess (>97%) with cost-effective and scalable processes, reducing operational costs and simplifying validation and operation compared to chromatographic methods.
Implementation Method 1
The use of chiral substituted tartaric acid esters to form diastereomeric salts with the racemic mixture, allowing for efficient separation of enantiomers
Implementation Method 2
efficient separation of enantiomers through conventional pilot plant equipment
Implementation Method 3
subsequent treatment with bases to release the desired enantiomer
Implementation Method 4
subsequent treatment with bases to release the desired enantiomer
Data Source
AI summary
The present invention relates to a novel and improved process for preparing (4S)-4-(4-cyano-2-methoxyphenyl)-5-ethoxy-2,8-dimethyl-1,4-dihydro-1,6-naphthyridine-3-carboxamide of the formula (I)and also to the preparation of the enantiomer (Ia) by racemate resolution using chiral substituted tartaric acid esters of the general formulae (IIIa) and (IIIb)where Ar represents a substituted or unsubstituted aromatic or heteroaromatic radical.