Niraparib Intermediate Synthesis via Base-Catalyzed Cyclization
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Solution Overview
Problem
Existing processes for preparing (S)-4-(piperidin-3-yl)aniline and tert-butyl (S)-3-(4-aminophenyl)piperidin-1-carboxylate for the anti-tumor drug niraparib involve catalytic reduction and chiral separation, leading to high equipment requirements, complex operations, unfavorable industrial production, high costs, and low product enantiomeric excess (ee) values.
Innovation Solution
A process that eliminates catalytic reduction and chiral separation by conducting a cyclization reaction in the presence of a base, using a conventional solvent like DMF or acetonitrile, and involving recrystallization to achieve high product ee values with lower equipment and operational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If catalytic reduction and chiral separation are used to prepare (S)-4-(piperidin-3-yl)aniline, then the product enantiomeric excess is improved, but the equipment requirements and operational complexity increase
Solution Approach 1:
The patent extracts and removes the problematic catalytic reduction and chiral separation steps from the synthesis pathway. Instead of using these complex operations, the invention employs a straightforward cyclization reaction that directly produces the desired (S)-enantiomer through inherent stereochemical control in the reaction mechanism, eliminating the need for specialized equipment and complex operational procedures
Solution Approach 2:
The synthesis is segmented into distinct functional stages where the cyclization reaction is designed to simultaneously achieve ring formation and stereoselective product generation. This segmentation allows the reaction to self-determine the stereochemistry without requiring external chiral separation equipment or catalysts
2Manufacturing precision
If catalytic reduction and chiral separation are used to prepare (S)-4-(piperidin-3-yl)aniline, then the product enantiomeric excess is improved, but the operational complexity increases
Solution Approach 1:
The patent removes the operationally complex catalytic reduction and chiral separation steps, replacing them with a simple cyclization reaction that proceeds under常规 conditions. The reaction requires only standard laboratory equipment and routine operational procedures, significantly reducing operational complexity while maintaining high enantiomeric excess through the reaction's inherent stereochemical control
Solution Approach 2:
The cyclization reaction is designed to be self-determining in terms of stereochemistry. The reaction conditions and substrate structure work together to automatically generate the desired (S)-enantiomer without requiring external intervention through chiral catalysts or separation processes, making the operation straightforward and self-explanatory
3Manufacturing precision
If catalytic reduction and chiral separation are used to prepare (S)-4-(piperidin-3-yl)aniline, then the product enantiomeric excess is improved, but the production feasibility for industrial scale decreases
Solution Approach 1:
The patent extracts the industrially problematic catalytic reduction and chiral separation steps, replacing them with a cyclization reaction that is inherently suitable for scale-up. The reaction uses conventional reagents and conditions that are easy to handle at industrial scale, eliminating the need for expensive catalysts, specialized equipment, and complex separation infrastructure
Solution Approach 2:
The invention employs inexpensive, readily available reagents and conventional solvents for the cyclization reaction, avoiding the need for expensive chiral catalysts or specialized materials. The reaction conditions are designed to be robust and forgiving, allowing for straightforward industrial implementation without requiring expensive infrastructure or highly trained personnel
4Productivity
If catalytic reduction with precious metals is used, then the product yield is achieved, but the production cost increases
Solution Approach 1:
The patent removes the expensive precious metal catalysts from the synthesis pathway and replaces them with a cyclization reaction that uses inexpensive, readily available reagents. The reaction maintains high productivity and yield through its efficient mechanistic pathway while eliminating the need for costly catalytic materials and the associated infrastructure
Solution Approach 2:
The invention employs cheap, conventional reagents and solvents for the cyclization reaction, replacing expensive precious metal catalysts. The reaction conditions are designed to be robust and forgiving, allowing for straightforward industrial implementation without requiring expensive infrastructure or highly trained personnel, thereby significantly reducing production costs while maintaining high yield
5Manufacturing precision
If chiral separation is used to prepare (S)-4-(piperidin-3-yl)aniline, then the product enantiomeric excess is improved, but the waste generation increases
Solution Approach 1:
The patent removes the chiral separation step that generates significant waste, including spent resolving agents, solvents, and discarded enantiomers. Instead, the cyclization reaction directly produces the desired (S)-enantiomer with high stereoselectivity, eliminating the need for separation and thereby preventing waste generation at its source
Solution Approach 2:
Rather than producing a racemic mixture and then separating the desired enantiomer (which generates waste), the invention inverts the approach by designing the cyclization reaction to directly produce only the desired (S)-enantiomer through inherent stereochemical control. This inversion eliminates the need for separation and prevents waste generation
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 a more efficient, cost-effective, and environmentally friendly production method with higher product ee values, reducing waste and the need for heavy metals and phosphorus, thus enhancing industrial feasibility.
Implementation Method 1
conducting a cyclization reaction of compound e in a solvent and in the presence of a base to give compound f
Implementation Method 2
in the presence of a base to give compound f
Implementation Method 3
involving recrystallization to achieve high product ee values
Data Source
Figure 1a~1c
AI summary
Disclosed is a process for preparing an intermediate of anti-tumor drug niraparib and an intermediate thereof. The present invention discloses a process for preparing compound (f), which comprises conducting a cyclization reaction of compound (e) in a solvent and in the presence of a base to give compound (f). The process of the present invention does not involve the steps of catalytic reduction or catalytic coupling reaction of precious metals and chiral separation, which has advantages such as low equipment requirements, simple operation, favorable industrial production, avoiding waste liquid containing heavy metals and phosphorus, low cost and high product ee value.