3,5-Dimethyldodecanoic Acid Synthesis via 1,4-Addition
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Solution Overview
Problem
Current methods for producing 3,5-dimethyldodecanoic acid, a sex pheromone of the California prionus beetle, are inefficient and costly due to high costs of starting materials, low yields, and the need for multiple steps and purification methods like silica gel flash chromatography, making industrial-scale production challenging.
Innovation Solution
A method involving the conversion of 2-methylnonyl halide to a 2-methylnonyl metal reagent, followed by 1,4-addition to 2-ethylidene malonic acid ester, and subsequent decarboxylation to produce 3,5-dimethyldodecanoic acid, allowing for industrial production through distillation purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods (bromination of 2-methyl-1-nonanol, Grignard reagent, β-butyrolactone coupling) are used, then 3,5-dimethyldodecanoic acid can be synthesized, but the production cost is high and purification requires complex silica gel flash chromatography
Solution Approach 1:
The invention extracts and eliminates the need for complex silica gel flash chromatography by designing a synthesis route where the product can be purified by simple distillation. The key is selecting 2-ethylidene malonic acid ester as the coupling partner, which enables straightforward purification without requiring complex chromatographic separation equipment and procedures.
Solution Approach 2:
The invention replaces expensive β-butyrolactone with more economical 2-ethylidene malonic acid ester as the coupling reagent. This substitution reduces material costs while simplifying the purification process, making the overall synthesis more economically viable for industrial production.
2Quantity of substance
If Petrov et al.'s method (ethyl malonate alkylation with heptyl magnesium bromide) is used, then 3,5-dimethyldodecanoic acid can be synthesized, but the alkylation yield is only 32% and severe conditions are required
Solution Approach 1:
The invention changes the reaction parameters by using 2-ethylidene malonic acid ester instead of ethyl malonate, and employing copper(I) catalyst with specific ligands. These parameter changes enable the reaction to proceed under milder conditions with significantly improved yield, avoiding the need for severe reaction conditions required by conventional methods.
Solution Approach 2:
The invention introduces copper(I) catalyst with ligands (such as triethyl phosphite or 2,3-O-isopropylidene-2,3-O-isopropylidene-1,4-dioxane) as intermediaries to facilitate the coupling reaction. These catalysts mediate the reaction between 2-methylnonyl metal reagent and 2-ethylidene malonic acid ester, enabling high yield under mild conditions without requiring severe reaction parameters.
3Manufacturing precision
If Millar et al.'s asymmetric synthesis method is used, then stereoselective 3,5-dimethyldodecanoic acid can be produced, but the number of steps is six and total yield is only 1.7%
Solution Approach 1:
The invention segments the synthesis into fewer, more efficient steps by using 2-ethylidene malonic acid ester as a key intermediate that enables direct coupling. This segmentation reduces the six-step asymmetric synthesis to a more streamlined process with higher overall yield, while maintaining stereoselectivity through the inherent chirality of the starting materials and copper-catalyzed asymmetric induction.
Solution Approach 2:
The invention performs preliminary action by pre-forming the 2-methylnonyl metal reagent and preparing 2-ethylidene malonic acid ester before the coupling step. This preliminary preparation allows the main coupling reaction to proceed efficiently in fewer steps with higher yield, avoiding the need for multiple sequential asymmetric transformations required by conventional methods.
4Manufacturing precision
If conventional methods are used, then 3,5-dimethyldodecanoic acid can be produced, but multiple purification steps with silica gel flash chromatography are required
Solution Approach 1:
The invention extracts and eliminates the need for time-consuming silica gel flash chromatography by designing a synthesis route where the product can be purified by simple distillation. This extraction of the complex purification step dramatically reduces the time required while maintaining product purity.
Solution Approach 2:
The invention enables continuous useful action by using distillation as the purification method, which can be easily scaled and performed continuously compared to batch chromatography. This continuous purification approach reduces overall production time and increases efficiency while maintaining product quality.
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 achieves high yields with fewer steps and eliminates the need for costly reagents and complex purification processes, making it feasible for industrial-scale production of 3,5-dimethyldodecanoic acid.
Implementation Method 1
1,4-addition of the 2-methylnonyl metal reagent (2) to 2-ethylidene malonic acid ester (3)
Implementation Method 2
subjecting the 2-(1,3-dimethyldecyl)malonic acid ester (4) to decarboxylation or dealkoxycarbonylation reaction to obtain 3,5-dimethyldodecanoic acid (5)
Implementation Method 3
industrial production through distillation purification
Data Source
AI summary
Provided is a short process for simply and efficiently producing 3,5-dimethyldodecanoic acid, which is an active ingredient of the pheromone of California prionus. More specifically provided is a method for producing 3,5-dimethyldodecanoic acid (5) comprising the steps of: converting 2-methylnonyl halide (1) to a 2-methylnonyl metal reagent (2), and reacting the 2-methylnonyl metal reagent (2) with 2-ethylidene malonic acid ester (3) to form 2-(1,3-dimethyldecyl)malonic acid ester (4) as a result of 1,4-addition of the 2-methylnonyl metal reagent (2) to the 2-ethylidene malonic acid ester (3), as shown in the following scheme: