Pyroxasulfone Synthesis Without DMF for Higher Purity and Yield
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Solution Overview
Problem
Existing processes for preparing pyroxasulfone suffer from the formation of undesired by-products that are difficult to separate due to structural similarity, impacting purity and yield, and the use of solvents like DMF poses health hazards and recovery challenges at industrial scales.
Innovation Solution
A process for preparing pyroxasulfone and its intermediates is developed without N,N-dimethyl formamide, using alternative solvents and bases, and optimizing reaction conditions to minimize impurities and improve yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If N,N-dimethyl formamide is used as a solvent in the reaction system, then the reaction can proceed, but health hazards arise and solvent recovery becomes difficult at industrial scale
Solution Approach 1:
The patent removes N,N-dimethyl formamide from the reaction system and replaces it with alternative solvents such as ethanol, isopropanol, or their mixtures with water. This extraction of the harmful solvent eliminates the associated health hazards and recovery difficulties while maintaining the reaction's feasibility through the use of safer, more easily recoverable alternative solvents.
Solution Approach 2:
The patent changes the solvent parameter from N,N-dimethyl formamide to alternative solvents like ethanol or isopropanol. This parameter change maintains the chemical reactivity needed for the reaction to proceed while improving safety and ease of recovery, as these alternative solvents have lower toxicity and are more readily separable from the reaction mixture.
2Ease of manufacture
If multiple solvents (ethanol, water, DMF) are used in the reaction system, then the reaction can be carried out, but solvent recovery becomes difficult at industrial scale
Solution Approach 1:
The patent extracts and removes N,N-dimethyl formamide from the multi-solvent system, retaining only ethanol and water. This reduction in the number of solvents simplifies the recovery process at industrial scale, as fewer solvents mean fewer separation steps and lower operational complexity, while still providing adequate reaction medium and functionality.
Solution Approach 2:
The patent uses ethanol and water as universal solvents that serve multiple functions: they provide the reaction medium, facilitate solvent recovery through simple evaporation or extraction, and maintain reaction feasibility. This multi-functionality eliminates the need for specialized solvents like DMF, thereby simplifying the overall process and improving recoverability.
3Ease of manufacture
If the reaction is carried out with conventional solvents, then the process can be executed, but impurities are formed that are difficult to separate due to structural similarity
Solution Approach 1:
The patent changes the solvent parameter from conventional solvents like N,N-dimethyl formamide to alternative solvents such as ethanol or isopropanol. This parameter change not only improves safety and recovery but also alters the reaction environment in a way that reduces the formation of structurally similar impurities, thereby improving product purity and ease of separation.
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 high-purity pyroxasulfone with reduced impurities and improved yield, addressing safety and scalability issues in industrial production.
Implementation Method 1
condensing a compound of formula (III) or salts thereof with a compound of formula (IV)
Implementation Method 2
Compound of formula (IIa) was then subjected to oxidation to obtain pyroxasulfone of formula (I)
Data Source
AI summary
The present invention relates to a process for preparation of 3-[5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)pyrazo 1-4-ylmethylsulfonyl]-4,5-dihydro-5,5-dimethyl-1,2-oxazole and its intermediates. The present invention provides a process for preparation of 3-({[5-fluoro-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl]methyl}sulfanyl)-5,5-dimethyl-4,5-dihydro-1,2-oxazole and 3-({[5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl]methyl}sulfanyl)-5,5-dimethyl-4,5-dihydro-1,2-oxazole in the absence of N,N-dimethyl formamide.