Continuous N-phenylpyrazole-1-carboxamide Synthesis
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Solution Overview
Problem
Existing methods for preparing N-phenylpyrazole-1-carboxamides or N-pyridinylpyrazole-1-carboxamides are inefficient and costly, particularly when scaled up for commercial production, and lack the flexibility and safety of continuous processes.
Innovation Solution
A continuous process involving the coupling of carboxylic acids with anthranilamides using a sulfonyl chloride, which includes continuously charging the reactants into a reaction zone and subsequently transferring the mixture to a quench zone and then an isolation zone, allowing for improved control and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch processing methods are used for preparing N-phenylpyrazole-1-carboxamides, then the process is simpler to implement, but the productivity and safety are reduced
Solution Approach 1:
The patent implements a continuous processing method where reactants are continuously fed through a reaction zone, quench zone, and isolation zone rather than using batch processing. This continuous flow approach increases throughput and productivity while maintaining process control through standardized equipment modules.
Solution Approach 2:
The continuous process is divided into distinct functional zones (reaction zone, quench zone, isolation zone) that can be implemented as separate reactor modules. This segmentation allows for optimized processing in each zone while maintaining overall process simplicity through modular design.
2Reliability
If larger quantities of reactive chemicals are used in batch processes, then the reaction can proceed to completion, but safety risks increase
Solution Approach 1:
By continuously processing small amounts of reactants through the reaction and quench zones, the system maintains high safety (minimizing reactive chemical inventory) while achieving high throughput through continuous operation. The process never accumulates large quantities of intermediates or products in reactive states.
Solution Approach 2:
The rapid quenching step immediately follows the reaction zone, quickly converting reactive intermediates to stable products. This 'rushing through' the reactive state minimizes the time reactive chemicals are present, enhancing safety without reducing productivity.
3Manufacturing precision
If conventional coupling methods are used, then the reaction can proceed, but new impurities are formed reducing manufacturing precision
Solution Approach 1:
The patent uses an activated ester intermediate formed in situ during the coupling reaction. This intermediary species reacts selectively with the amine to form the desired amide product while minimizing side reactions and impurity formation, thereby improving product purity without complicating the manufacturing process.
Solution Approach 2:
The continuous flow process maintains optimal reaction conditions throughout the reaction zone, preventing impurity formation through consistent mixing and temperature control. The continuous operation eliminates the variability associated with batch processing, improving manufacturing precision.
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 continuous process enhances safety by minimizing reactive chemicals, improves throughput, and achieves high yields without forming new impurities, making it suitable for large-scale commercial production.
Implementation Method 1
combining (1) a carboxylic acid compound of Formula 2, (2) an aniline compound of Formula 3; and (3) a sulfonyl chloride to form the compound of Formula 1
Data Source
AI summary
A method is disclosed for preparing compounds of Formula 1 by combining compounds of Formulae 2 and 3 and a sulfonyl chloride in a continuous process.