Sulfinpyrazone Preparation via Electrocatalytic Oxidation
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Solution Overview
Problem
The existing methods for synthesizing sulfinpyrazone are lengthy, have low yield, and face challenges in controlling the oxidation step, leading to over-oxidation issues.
Innovation Solution
A two-step method involving electrocatalytic oxidation and nucleophilic substitution using thiophenol as the raw material, which eliminates the need for hydrogen peroxide and reduces over-oxidation, resulting in a more efficient and environmentally friendly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the classical method using hydrogen peroxide and acetic acid for oxidation is used, then the oxidation reaction can proceed, but the thioether is easily over-oxidized to sulfone making it difficult to control the product to remain on the step of obtaining sulfoxide
Solution Approach 1:
The patent changes the oxidation method from chemical oxidation (hydrogen peroxide) to electrochemical oxidation. By controlling electrical parameters (current, voltage, time) instead of chemical reagent concentration and addition rate, the oxidation process achieves better precision and reliability, preventing over-oxidation to sulfone while ensuring complete conversion to sulfoxide
Solution Approach 2:
The patent replaces the chemical oxidation system (hydrogen peroxide/acetic acid) with an electrochemical oxidation system. This substitution eliminates the need for harsh chemical oxidants and provides more controllable reaction conditions, thereby improving product control precision and preventing over-oxidation
2Productivity
If the multi-step synthesis route is used, then the complete transformation can be achieved, but the steps are long and tedious with low yield
Solution Approach 1:
The patent combines multiple separate synthesis steps into a more streamlined process. By using electrochemical oxidation to reliably convert thioether to sulfoxide in situ, and optimizing the subsequent nucleophilic substitution conditions, the method reduces the number of isolation and purification steps, thereby improving overall productivity and reducing synthesis time
Solution Approach 2:
The patent enables continuous reaction processes by performing the electrochemical oxidation and nucleophilic substitution in a more integrated manner. The electrochemical method allows for continuous monitoring and control, maintaining optimal reaction conditions throughout the process, which improves efficiency and reduces total synthesis time
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 method significantly shortens the synthesis steps, increases yield, avoids environmental pollution, and improves reaction selectivity, producing sulfinpyrazone with high purity and stability.
Implementation Method 1
dissolving thiophenol as shown in formula 3 and electrolyte in a mixed solution of 1,2-dichloroethane and water and reacting by passing the current for 1 to 48 hours to obtain 2-chloroethyl phenyl sulfoxide
Implementation Method 2
mixing and dissolving 2-chloroethyl phenyl sulfoxide as shown in formula 2, 1,2-diphenyl-3,5-pyrazolidinedione as shown in formula 4, the base and the additive in the solvent, and reacting by heating under nitrogen atmosphere
Data Source
AI summary
The present disclosure discloses a method for the preparation of sulfinpyrazone, which is produced in two steps with a total yield of 48%, wherein thiophenol as the starting material is electrocatalytically coupled with dichloroethane to obtain 2-chloroethyl phenyl sulfoxide, which then undergoes a substitution reaction with 1,2-diphenyl-3,5-pyrazolidinedione to produce sulfinpyrazone. Compared with the prior art, the present method is characterized by high yield, short steps, less three wastes, good chemical selectivity, no need to use strong bases and oxidants, safe and simple operation, and easy to realize industrial production.