Azoxystrobin Preparation via DABCO Catalyst Addition Order
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Solution Overview
Problem
The existing methods for preparing azoxystrobin fungicide are limited by the yield and reaction rate, which can be affected by the order of addition of reaction components when using DABCO as a catalyst.
Innovation Solution
A process involving the controlled addition of DABCO and 2-cyanophenol or its salt to specific compounds, ensuring DABCO is not added last, and using an acid acceptor to inhibit unwanted reactions, promoting higher yields and faster reaction rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DABCO is added last to the reaction mixture, then the reaction can proceed, but the yield decreases and reaction rate slows due to formation of non-active species
Solution Approach 1:
The patent applies preliminary action by adding DABCO to the reaction mixture before adding the final component (either 2-cyanophenol or the compound of formula III), ensuring the catalyst is already present and active when the reaction proceeds. This prevents the formation of non-active species that would occur if DABCO were added last, thereby maintaining both high reaction rate and yield.
2Ease of operation
If DABCO is added to the compound of formula II or III in the absence of 2-cyanophenol or its salt, then the catalyst can be pre-mixed, but non-active species form reducing yield
Solution Approach 1:
The patent applies parameter changes by controlling the order of addition of reaction components. Specifically, it specifies that DABCO should not be added last to the reaction mixture, and should not be added to compound of formula II or III in the absence of 2-cyanophenol or its salt. This change in the sequence parameter prevents the formation of non-active species while still allowing for convenient catalyst pre-mixing with other components in the correct sequence.
3Adaptability or versatility
If the reaction components are added in any order, then the process is flexible, but the yield and reaction rate are suboptimal
Solution Approach 1:
The patent applies dynamics by providing multiple acceptable addition sequences (i through x) that are all optimized for yield and reaction rate. Rather than a single rigid procedure, the patent offers dynamic flexibility in the order of addition, allowing adaptation to different laboratory conditions while maintaining optimal performance. All specified sequences ensure DABCO is present before the final component is added, preventing non-active species formation.
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 enhances the yield and reaction rate of azoxystrobin production by preventing non-active species formation and optimizing catalyst activity, leading to improved product efficiency.
Implementation Method 1
reacting a compound of formula (II) with 2-cyanophenol, or a salt thereof in the presence of between 0.1 and 40 mol % of 1,4-diazabicyclo[2.2.2]octane (DABCO)
Implementation Method 2
adding 1,4-diazabicyclo[2.2.2]octane to an acidic solution of the compound of formula (II) or the compound of formula (III) in which sufficient acid is present to convert all of the 1,4-diazabicyclo[2.2.2]octane to a salt
Data Source
AI summary
The present invention relates, inter alia, to a process for preparing a compound of formula (I): using, as a catalyst 1,4-diazabicyclo[2.2.2]octane.