Dronedarone Synthesis via Selective Acyl Cleavage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for preparing dronedarone are economically unfavorable and unsuitable for industrial application due to the use of mutagenic compounds and harmful reagents, as well as issues with impurity and yield in the final product.
Innovation Solution
A novel process involving the selective cleavage of the acyl group from a benzofuran derivative in an alcoholic solvent with an alkali alcoholate or inorganic acid, followed by acylation, mesylation, and reaction with 4-(3-di-n-butylamino-propoxy)benzoyl chloride, to produce dronedarone in good yield and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the compound of formula IX is heated in the presence of aluminum chloride to obtain compound of formula X, then the hydroxy group is introduced, but the process uses harmful reagents and produces mutagenic intermediates
Solution Approach 1:
The invention extracts and removes the harmful aluminum chloride catalyst from the reaction system, replacing it with a solid acid catalyst that can be easily separated and does not produce harmful byproducts. This eliminates the mutagenic intermediate formation while maintaining the hydroxy group introduction capability
Solution Approach 2:
The invention uses a solid acid catalyst that can be used in excess and then easily removed by filtration, replacing the expensive and harmful aluminum chloride. The solid catalyst serves its purpose and is discarded without causing long-term environmental or health issues
2Manufacturing precision
If the selective mesylation of the amino group of compound of formula XII is performed, then dronedarone is formed, but the reaction is difficult and produces double mesylated derivative impurities
Solution Approach 1:
The invention performs preliminary protection of the amino group as a salt (using hydrochloric acid or other acids) before the mesylation step. This preliminary action makes the amino group non-nucleophilic, preventing double mesylation, and allows selective mesylation to occur only at the desired position
Solution Approach 2:
The invention introduces an intermediary substance (acid) that temporarily modifies the amino group's reactivity. The acid forms a salt with the amino group, acting as an intermediary that prevents unwanted side reactions while allowing the desired mesylation to proceed selectively
3Manufacturing precision
If the linear synthesis method is used to build up the molecule stepwise, then the desired product is obtained, but the process is economically unfavourable
Solution Approach 1:
The invention inverts the traditional linear synthesis approach by using a convergent synthesis strategy where key fragments are prepared separately and then combined in a final coupling step. This reversal of the synthesis logic reduces the total number of steps and improves economic efficiency
Solution Approach 2:
The invention merges multiple synthesis routes into a single convergent pathway where intermediates are combined in a key Friedel-Crafts acylation step. This merging approach reduces the total number of reaction steps and improves overall yield and economic efficiency
4Manufacturing precision
If the Friedel-Crafts reaction is performed with dibutylamino group present, then the coupling occurs, but impure dronedarone hydrochloride is formed that requires extensive purification
Solution Approach 1:
The invention performs preliminary protection of the dibutylamino group by converting it to a hydrochloride salt before the Friedel-Crafts reaction. This preliminary action prevents the amino group from interfering with the reaction and simplifies subsequent purification by allowing direct filtration of the product
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 yield and purity of dronedarone, avoiding the use of harmful reagents and improving the economic viability for industrial application while minimizing impurities.
Implementation Method 1
selective cleavage of the acyl group from a benzofuran derivative in an alcoholic solvent with an alkali alcoholate or inorganic acid
Implementation Method 2
followed by acylation, mesylation, and reaction with 4-(3-di-n-butylamino-propoxy)benzoyl chloride
Implementation Method 3
reacted with anisoyl chloride under Friedel-Crafts conditions
Data Source
AI summary
The subject of the invention is a novel process for the preparation of N-[2-n-butyl-3-{4-[(3-di-n-butylamino)-propoxy]benzoyl}benzofuran-5-yl]-methanesulfonamide of formula I:and pharmaceutically acceptable salts thereof wherein the acyl group of the benzofuran derivative of the general formula II:where R represents C1-4 alkyl-, C1-4 alkoxy- or aryl group, is selectively cleaved and if desired, the resulting compound of formula I is transformed into its salt.