Telescopic Synthesis of Arthropodicidal Intermediate via Phase Transfer Catalysis
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Solution Overview
Problem
Current methods for preparing methyl chloroformyl[4-(trifluoromethoxy)phenyl]carbamate, a key intermediate for indoxacarb, involve the use of sodium hydride and organic bases, which pose safety and environmental concerns, necessitating a more efficient and safer process for large-scale commercial production.
Innovation Solution
A process involving the reaction of compound IV with phosgene or its derivative in the presence of a phase transfer catalyst, alkaline base, and hydrocarbon solvent, without organic base or metal hydride, allowing for the telescopic preparation of methyl chloroformyl[4-(trifluoromethoxy)phenyl]carbamate, and subsequently indoxacarb.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sodium hydride or metal hydrides are used in the preparation of methyl chloroformyl[4-(trifluoromethoxy)phenyl]carbamate, then the reaction proceeds effectively, but safety risks increase and environmental harm is caused
Solution Approach 1:
The patent removes hazardous materials (sodium hydride, organic bases) from the reaction system and replaces them with safer alternatives (aqueous alkali metal hydroxide solution, phase transfer catalyst), thereby eliminating safety risks and environmental harm while maintaining reaction effectiveness
Solution Approach 2:
The patent introduces a phase transfer catalyst as an intermediary substance that enables the reaction between aqueous alkali metal hydroxide solution and organic substrates without requiring hazardous metal hydrides, thus resolving the contradiction between reaction effectiveness and safety
2Ease of manufacture
If organic bases and amine bases are used in the preparation process, then the intermediate can be prepared, but environmental impact increases and waste treatment becomes necessary
Solution Approach 1:
The patent extracts and removes organic bases and amine bases from the reaction system, replacing them with aqueous alkali metal hydroxide solution, thereby eliminating amine waste generation and environmental impact while maintaining the ability to prepare the intermediate
Solution Approach 2:
The patent changes the physical and chemical parameters of the base from organic/amine-based to aqueous hydroxide-based, which fundamentally alters the waste profile from environmentally harmful amine wastes to easily treatable aqueous waste, thus resolving the contradiction between ease of manufacture and environmental impact
3Manufacturing precision
If multiple separate steps are used for preparation, then each step can be optimized, but process complexity and time consumption increase
Solution Approach 1:
The patent combines multiple separate preparation steps into a single telescopic one-pot process where the intermediate is formed and reacts further without isolation, thereby reducing process complexity and time consumption while maintaining manufacturing precision through controlled reaction conditions
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 approach eliminates the need for hazardous materials, reduces environmental impact, and enhances the efficiency of the synthesis, making it suitable for safe and economic commercial operations.
Implementation Method 1
reaction of compound of formula (IV) with phosgene or phosgene derivative in the presence of phase transfer catalyst, alkaline base and hydrocarbon organic solvent
Implementation Method 2
reaction of compound of formula (IV) with phosgene or phosgene derivative
Implementation Method 3
reaction of compound of formula (IV) with phosgene or phosgene derivative in the presence of phase transfer catalyst, alkaline base and hydrocarbon organic solvent
Data Source
AI summary
The present invention pertains to a process for preparing of methyl chloroformyl[4-(trifluoromethoxy)phenyl]carbamate of formula I as intermediate in the preparation of arthropodicidal indoxacarb, comprising reaction of compound of formula (IV) with phosgene or phosgene derivative in the presence of phase transfer catalyst, alkaline base and hydrocarbon organic solvent and in the absence of organic base and metal hydride. This invention also pertains to a telescopic process for preparation of methyl chloroformyl[4-(trifluoromethoxy)phenyl]carbamate of formula I comprising preparation of isocyanate of formula (II) by reaction of compound of aniline derivative of formula (III) with phosgene or phosgene derivative in the presence of dimethylcarbonate and hydrocarbon organic solvent; following the preparation of compound of formula (IV) by reaction of compound of formula (II) with methanol and distillation out of dimethylcarbonate and reaction of compound of formula (IV) with phosgene or phosgene derivative in the presence of phase transfer catalyst, alkaline base and hydrocarbon organic solvent.