Chroman Compound Synthesis Without Costly Chiral Resolution
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Solution Overview
Problem
The existing methods for synthesizing 2-methyl-5-((2R,4S)-2-((((R)-1-(naphthalen-1-yl)ethyl)amino)methyl)chroman-4-yl)benzoic acid are inefficient, costly, and not suitable for industrial scale due to the difficulty and cost of chiral resolution of intermediates, which affects the overall yield.
Innovation Solution
A novel, enantioselective method is developed for the synthesis of 2-methyl-5-((2R,4S)-2-((((R)-1-(naphthalen-1-yl)ethyl)amino)methyl)chroman-4-yl)benzoic acid and its salts, using novel intermediates such as Compound 3, Compound 4, Compound 5, and others, which are synthesized through specific steps involving coupling reactions, asymmetric hydrogenation, and protection/deprotection reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chiral resolution of racemic chroman-2-carboxylic acid is carried out to obtain the desired (R) chroman-2-carboxylic acid, then the stereochemistry of the final product is improved, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent applies preliminary action by introducing a chiral auxiliary group (Boc or Cbz) during the synthesis of chroman-2-carboxylic acid, which pre-establishes the desired (R) configuration before the final product formation. This eliminates the need for subsequent chiral resolution steps, as the chirality is built into the molecule during synthesis rather than separated afterward.
Solution Approach 2:
The patent uses chiral auxiliaries (Boc or Cbz groups) as intermediaries to transfer chirality during the synthesis process. These auxiliary groups serve as temporary chiral determinants that guide the formation of the (R) configuration in the chroman-2-carboxylic acid intermediate, which is then removed in the final step to yield the enantiomerically pure product.
2Manufacturing precision
If chiral resolution is performed to obtain enantiomerically pure (R) chroman-2-carboxylic acid, then the enantiomeric excess is improved, but the overall yield decreases
Solution Approach 1:
The patent applies preliminary action by establishing the (R) configuration during the synthesis of chroman-2-carboxylic acid through chiral auxiliary groups, rather than separating enantiomers afterward. This approach ensures that only the desired (R) enantiomer is formed in the first place, eliminating the yield loss that would occur during chiral resolution and achieving both high enantiomeric excess and high overall yield.
Solution Approach 2:
The patent converts the potential harm of forming racemic mixtures into a benefit by using chiral auxiliaries to selectively form only the desired (R) enantiomer during synthesis. The chiral auxiliary groups act as templates that guide the formation of the correct stereoisomer, turning what would normally be a wasteful resolution process into an efficient synthesis pathway that maintains high yield while achieving enantiomeric purity.
3Device complexity
If conventional synthesis methods are used to prepare 2-methyl-5-((2R,4S)-2-((((R)-1-(naphthalen-1-yl)ethyl)amino)methyl)chroman-4-yl)benzoic acid, then the route is simpler, but the cost and time consumption increase
Solution Approach 1:
The patent applies preliminary action by incorporating chiral auxiliary groups (Boc or Cbz) during the early stages of synthesis, which pre-determines the stereochemistry of subsequent steps. This eliminates the need for time-consuming chiral resolution operations later in the process, thereby reducing overall synthesis time while maintaining route simplicity.
Solution Approach 2:
The patent ensures continuity of useful action by using chiral auxiliary groups that remain throughout the synthesis sequence, guiding each step toward the desired (R) configuration without requiring interruption for resolution operations. This continuous chirality control streamlines the synthesis process and reduces total processing time compared to methods that require separate resolution steps.
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 new method provides a more efficient, cost-effective, and industrially advantageous process for the synthesis of the target compound, improving yield and simplifying the process by avoiding the need for costly chiral resolution.
Implementation Method 1
b) enantioselectively reducing the double bond of Compound 3 by asymmetric hydrogenation to obtain the optically active (R)—N—((R)-1-(naphthalen-1-yl)ethyl)-4-oxochromane-2-carboxamide (Compound 4)
Implementation Method 2
a) reacting 4-oxo-4H-chromene-2-carboxylic acid (Compound 1) with (R)-1-(naphthalen-1-yl)ethan-1-amine (Compound 2) in the presence of one or more coupling catalysts to obtain (R)—N-(1-(naphthalen-1-yl)ethyl)-4-oxo-4H-chromene-2-carboxamide (Compound 3)
Data Source
AI summary
This disclosure describes an economical and scalable method and process to synthesize the Calcium sensing receptor (CaSR) modulating agent 2-methyl-5-((2R,4S)-2-((((R)-1-(naphthalen-1-yl)ethyl)amino)methyl)chroman-4-yl)benzoic acid, its intermediates and pharmaceutically acceptable salts therefor. Uses of said intermediates for synthesis of compounds which may be intermediates to the synthesis of 2-methyl-5-((2R,4S)-2-((((R)-1-(naphthalen-1-yl)ethyl)amino)methyl)chroman-4-yl)benzoic acid are also described herein.