Vinylcyclopropane Synthesis via Optimized Base Ratios
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Solution Overview
Problem
Current methods for producing (1R,2S)/(1S,2R)-1-amino-1-alkoxycarbonyl-2-vinylcyclopropane are industrially disadvantageous due to low yields and the use of halogenated solvents, particularly dichloromethane, in solid-liquid phase reactions.
Innovation Solution
A method involving the reaction of a trans-2-butene derivative with malonic ester in the presence of alkali metal alkoxide or alkali metal hydride, optimizing the amount of base and malonic ester to achieve high yields of vinylcyclopropane ring diester, followed by hydrolysis and optical resolution to produce the desired compound in achiral or chiral forms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If trans-1,4-dibromo-2-butene is reacted with diethyl malonate in dichloromethane in the presence of potassium hydroxide and tricaprylylmethylammonium chloride, then 1,1-di-ethoxycarbonyl-2-vinylcyclopropane is obtained at a yield of 89%, but the method uses halogenated solvents and is a solid-liquid two phase reaction which is industrially disadvantageous
Solution Approach 1:
The patent changes the physical state parameters of the reaction system by using alkali metal alkoxides or alkali metal hydrides in appropriate amounts to transform the solid-liquid two-phase reaction into a more suitable system for industrial production, while maintaining high yield through optimized reagent ratios
Solution Approach 2:
The patent replaces expensive and environmentally problematic halogenated solvents like dichloromethane with more economical and industrially friendly solvents or solvent-free conditions, achieving comparable or better yields while improving industrial applicability
2Reliability
If dichloromethane is used as a solvent in the cyclopropane ring formation reaction, then the reaction proceeds effectively, but the use of halogenated solvents creates industrial disadvantages
Solution Approach 1:
The patent eliminates the harmful effect of halogenated solvents by replacing them with non-halogenated alternatives or conducting the reaction under solvent-free conditions, while maintaining or improving reaction effectiveness through optimized base and malonic ester ratios that enhance reaction efficiency without requiring problematic solvents
3Ease of manufacture
If a solid-liquid two phase reaction is used for cyclopropane ring formation, then the reaction can proceed with certain reagents, but the reaction conditions are industrially disadvantageous
Solution Approach 1:
The patent optimizes the reaction parameters by carefully controlling the amount of base (alkali metal alkoxide or alkali metal hydride) and malonic ester to achieve complete dissolution or formation of a homogeneous reaction system, eliminating the solid-liquid two-phase condition and improving industrial efficiency while maintaining reaction feasibility
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 enables the production of (1R,2S)/(1S,2R)-1-amino-1-alkoxycarbonyl-2-vinylcyclopropane with improved yield and industrial applicability, suitable as a synthetic intermediate for therapeutic agents for hepatitis C.
Implementation Method 1
a method involving the reaction of a trans-2-butene derivative with malonic ester in the presence of alkali metal alkoxide or alkali metal hydride
Implementation Method 2
followed by hydrolysis and optical resolution to produce the desired compound
Data Source
AI summary
It is an object of the present invention to provide a novel method for producing (1R,2S)/(1S,2R)-1-amino-1-alkoxycarbonyl-2-vinylcyclopropane which is useful as a synthetic intermediate of therapeutic agents for hepatitis C and a synthetic intermediate thereof. According to the present invention, when a trans-2-butene derivative having a leaving group at each of the 1- and 4-positions is reacted with a malonic ester in the presence of a base, a specific amount of an alkali metal alkoxide or an alkali metal hydride is used as the base, and further a specific amount of a malonic ester is used to produce a cyclopropane diester, and further, chiral or achiral 1-amino-1-alkoxy-carbonyl-2-vinylcyclopropane and a salt thereof are synthesized using the cyclopropane diester.