Fluoxastrobin Synthesis via Controlled Chlorination of Diethyl Malonate
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Solution Overview
Problem
Existing methods for synthesizing fluoxastrobin result in significant formation of diethyl dichloro malonate impurities, leading to complex reaction mixtures and poor quality and yield of the final product, making it difficult to isolate pure fluoxastrobin.
Innovation Solution
A process involving controlled chlorination of diethyl malonate with a concentration of reactive chlorine between 0.01 to 5 mol %/minute, followed by specific intermediate reactions to minimize dihalo malonate impurities, allowing for the preparation of fluoxastrobin and intermediates in high purity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chlorination of diethyl malonate is performed using conventional chlorinating agents, then the reaction proceeds to form diethyl 2-chloromalonate, but significant amounts of diethyl dichloro malonate impurities are formed
Solution Approach 1:
The patent applies parameter changes by controlling the concentration of reactive chlorine in the reaction medium to be between 0.01 to 5 mol %/minute. This precise control of the chlorine concentration parameter prevents over-chlorination and forms diethyl dichloro malonate impurities, while still achieving complete chlorination to the desired product.
Solution Approach 2:
The patent implements feedback control by continuously monitoring and adjusting the chlorine concentration in the reaction medium. This feedback mechanism ensures that the chlorine concentration remains within the optimal range (0.01 to 5 mol %/minute), preventing both incomplete chlorination and excessive chlorination that would lead to impurity formation.
2Device complexity
If conventional chlorination methods are used, then the reaction is simple, but the reaction mixture becomes complex with multiple side products
Solution Approach 1:
The patent changes the parameter of reactive chlorine concentration to a controlled range (0.01 to 5 mol %/minute), which fundamentally alters the reaction outcome. This parameter control prevents the formation of multiple side products while maintaining a relatively simple reaction process, as the controlled chlorination proceeds through a more straightforward pathway.
3Manufacturing precision
If diethyl dichloro malonate impurities are present, then the reaction mixture is complex, but isolation of pure fluoxastrobin becomes extremely difficult
Solution Approach 1:
The patent applies preliminary anti-action by preventing the formation of diethyl dichloro malonate impurities in the first place through controlled chlorine concentration. By addressing the root cause (excessive chlorine) at the source, the patent avoids creating the complex mixture that would require difficult isolation procedures later in the process.
4Productivity
If uncontrolled chlorination is used, then the process is fast, but the yield and quality of fluoxastrobin are poor
Solution Approach 1:
The patent optimizes the parameter of reactive chlorine concentration (0.01 to 5 mol %/minute) to achieve both high yield and high quality. This optimized parameter range ensures complete chlorination for high yield while preventing over-chlorination that would reduce quality, thus resolving the contradiction between productivity and 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 process achieves fluoxastrobin with chemical purity of more than 99.5% and reduces dihalo malonate impurities, enabling commercial-scale production of high-quality fluoxastrobin.
Implementation Method 1
chlorinating compound of formula (2) with chlorine wherein the concentration of reactive chlorine in the reaction medium during the reaction is between 0.01 to 5 mol %/minute
Data Source
AI summary
The invention provides an improved process for the preparation of fluoxastrobin and intermediates thereof. The present invention provides a process for the preparation of fluoaxastrobin, 4,6-dichloro-5-fluoro-pyrimidine and diethyl 2-chloromalonate that are substantially free of unwanted impurities.