Convergent SNAr Synthesis of Acyclic HCV Protease Inhibitors
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Solution Overview
Problem
The existing methods for preparing acyclic compounds useful as agents for treating hepatitis C viral infections are inefficient, requiring numerous synthetic steps and low overall yield, and often utilize sequential building of groups rather than convergent synthesis.
Innovation Solution
A highly convergent synthetic process using SNAr assembly strategies with monopeptides, dipeptides, and tripeptides that eliminates the need to invert hydroxyproline stereochemistry, allowing the use of natural amino acids and resulting in crystalline intermediates for improved handling and storage, and involving a SNAr coupling reaction between a hydroxyproline compound and a quinoline compound to produce compounds of Formula (I).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional linear synthetic methods are used to prepare acyclic HCV protease inhibitors, then the synthesis can be performed with standard sequential steps, but the process requires numerous synthetic steps and has low overall yield
Solution Approach 1:
The synthesis is divided into independent modular fragments (quinoline-containing fragments and hydroxyproline-containing fragments) that can be prepared separately and then coupled together. This segmentation allows parallel preparation of multiple fragments, reducing the total number of sequential steps and improving overall yield by enabling convergent rather than linear assembly.
Solution Approach 2:
Multiple synthetic operations are merged into a single step through the development of a novel SNAr coupling reaction that combines fragment assembly with stereoselective bond formation. This merging reduces the number of discrete steps required and improves efficiency by performing multiple transformations in one operation.
2Productivity
If conventional methods are used, then the synthesis process is straightforward, but it requires many sequential steps and has poor efficiency
Solution Approach 1:
The hydroxyproline stereochemistry is established during the fragment synthesis stage rather than requiring inversion in a subsequent step. This preliminary action of setting the correct stereoconfiguration during fragment preparation eliminates time-consuming stereoinversion steps later in the sequence, thereby reducing overall synthetic time and improving efficiency.
Solution Approach 2:
Instead of inverting hydroxyproline stereochemistry as required by conventional methods, the invention uses the natural stereochemistry of L-hydroxyproline directly in the synthesis. This inversion of the conventional approach allows the use of readily available natural amino acids, eliminating the need for stereochemical inversion steps and reducing synthetic sequence length.
3Ease of manufacture
If natural amino acids are used as starting materials, then cost is reduced, but the synthesis must accommodate the natural stereochemistry without inversion
Solution Approach 1:
The invention inverts the conventional approach by accepting the natural L-stereochemistry of hydroxyproline rather than requiring inversion to achieve the desired configuration. This allows the use of inexpensive, readily available natural amino acids as starting materials, reducing cost while eliminating the need for costly and time-consuming stereochemical inversion steps.
Solution Approach 2:
The natural stereochemistry of L-hydroxyproline is utilized directly without requiring modification or inversion. The synthesis process serves itself by accommodating the natural configuration through the development of SNAr coupling conditions that work seamlessly with L-hydroxyproline stereochemistry, thereby reducing both cost and process complexity.
4Ease of operation
If crystalline intermediates are obtained, then handling and storage are improved, but the process requires additional purification steps
Solution Approach 1:
The synthesis methodology is designed to produce crystalline solids as intermediates and final products through controlled precipitation and crystallization. This phase transition from amorphous to crystalline form improves handling and storage properties while the crystallization process itself serves as an effective purification mechanism, reducing the need for additional complex purification 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
This process significantly reduces the number of synthetic steps, increases yield, and provides economic advantages by using less expensive natural amino acids, while also offering advantages in handling and storage due to the crystalline form of intermediates.
Implementation Method 1
The processes provided by the present invention utilize an SNAr assembly strategy... involving a SNAr coupling reaction between a hydroxyproline compound and a quinoline compound
Data Source
AI summary
Disclosed are highly convergent processes for preparing compounds of formula (I), which compounds are potent active agents for the treatment of hepatitis C virus (HCV) infection:The disclosed processes use SNAr-type coupling reactions between peptidic compounds having a hydroxyproline moiety of the following formula:and halogenated or sulfonated bromoquinoline compounds.