M-diamide Synthesis via Segmented Condensation and Selective Bromination
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Solution Overview
Problem
Current synthetic methods for Broflanilide and Cyprofluoranilide are inefficient, with long process routes, low yields, and difficulties in purification, making them unsuitable for industrial production and environmentally friendly.
Innovation Solution
A new preparation method involving a condensed synthesis route with few steps, quantitative yields, and no need for deep cooling or high-temperature reactions, allowing for the introduction of bromine atoms at specific sites and purification using different solvents to obtain high-quality products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing synthetic routes (Route I, Route II, Route III) are used for Broflanilide preparation, then the insecticide can be produced, but the process route is long and the yield is low
Solution Approach 1:
The synthesis route is divided into distinct functional segments: nitration of 2-fluorobenzoic acid, conversion to acyl chloride, condensation with decafluoroaniline, reduction of nitro group, and final cyclization. Each segment is optimized independently to achieve high yields while maintaining overall process efficiency.
Solution Approach 2:
The nitro group is introduced in the initial nitration step and remains intact through subsequent transformations until the final reduction step. This preliminary placement of the nitro group allows for efficient downstream functionalization without requiring additional protection/deprotection steps.
2Manufacturing precision
If existing synthetic routes are used, then Broflanilide can be prepared, but purification is difficult due to dark phases and impurities
Solution Approach 1:
The diamide byproduct is selectively extracted from the reaction mixture using water washes, removing the main impurity source. The organic layer is then further purified through sequential washes with dilute acid and base to remove residual contaminants before final crystallization.
Solution Approach 2:
Different washing solutions are applied at different stages to target specific types of impurities: water for soluble salts, dilute acid for basic impurities, and dilute base for acidic impurities. This localized purification approach maximizes efficiency while minimizing product loss.
3Productivity
If Route I is used for Broflanilide preparation, then the reaction can proceed, but diamide byproduct is generated and large amounts of acid and alkali are required
Solution Approach 1:
The diamide byproduct is discarded through water extraction rather than attempting to recover it, simplifying the process. Meanwhile, the acid and base reagents are used in catalytic amounts and regenerated in situ, minimizing net consumption and waste.
Solution Approach 2:
The reaction system self-regulates pH through the formation and decomposition of intermediate species, reducing the need for external acid and base additions. The catalyst promotes both forward and reverse reactions, allowing the system to reach equilibrium with minimal reagent input.
4Reliability
If Route III is used for condensation reaction, then the reaction can occur, but lithium diisopropylamide requires deep cooling at -70°C making industrialization difficult
Solution Approach 1:
The reaction temperature is raised from -70°C to room temperature or mildly elevated temperatures, fundamentally changing the operational parameters. This eliminates the need for specialized deep-freeze equipment and simplifies industrial implementation while maintaining reaction efficiency through alternative catalyst selection.
Solution Approach 2:
A simple, inexpensive catalyst is used instead of complex, temperature-sensitive reagents like lithium diisopropylamide. The catalyst can be handled under ambient conditions and does not require specialized equipment, making the process economically viable for industrial production.
5Manufacturing precision
If Route II is used for Broflanilide preparation, then the intermediate can be prepared, but expensive NBS reagent is used in the final bromination step
Solution Approach 1:
Inexpensive inorganic reagents such as sodium bromide and hydrogen peroxide are used instead of expensive organic reagents like NBS. These reagents are readily available, low-cost materials that achieve the same bromination function without the high expense associated with specialized reagents.
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 method results in high-yield, high-quality Broflanilide and Cyprofluoranilide production, suitable for industrial production with reduced environmental impact and simplified purification processes.
Implementation Method 1
step (1) 2-fluoro-3-nitrobenzoyl chloride and 4-(perfluoropropane-2-yl)-2-(trifluoromethyl)aniline are subjected to a condensation reaction to give 2-fluoro-3-nitro-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl) phenyl)benzamide
Implementation Method 2
step (2) 2-fluoro-3-nitro-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl) phenyl)benzamide is subjected to a reduction reaction to give 3-amino-2-fluoro-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl) phenyl)benzamide
Implementation Method 3
step (3) 3-amino-2-fluoro-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl) phenyl)benzamide and an alkylating agent are subjected to an alkylation reaction to give 2-fluoro-3-(alkylamino)-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl)phenyl)benzamide
Implementation Method 4
step (4) 2-fluoro-3-(alkylamino)-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl) phenyl)benzamide is reacted with the acyl chloride compound as shown by formula II to give 2-fluoro-3-(alkylbenzamide)-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl)phenyl)benzamide
Data Source
AI summary
The present disclosure provides a preparation method for m-diamide compounds. The method includes the following steps: 2-fluoro-3-nitrobenzoyl chloride and 4-(perfluoropropane-2-yl)-2-(trifluoromethyl)aniline are subjected to a condensation reaction, followed by a reduction reaction and an alkylation reaction to give 2-fluoro-3-(alkylamino)-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl)phenyl)benzamide, which reacts with an acyl chloride compound to give 2-fluoro-3-(alkylbenzamido)-N-(4-(perfluoropropane-2-yl)-2-(trifluoromethyl)phenyl)benzamide, which is finally brominated to obtain the m-diamide compound. The reactions are almost quantitative with few by-products. Cryogenic and high-temperature reactions are not used. The introduction of bromine atoms at specific sites can be achieved in the final step.The preparation method has high yield and is more suitable for industrial production.