Dabigatran Etexilate Intermediate Synthesis Yield
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Solution Overview
Problem
Current methods for preparing dabigatran etexilate intermediates face challenges such as low yield, side reactions, and purification difficulties, making them unsuitable for industrial production.
Innovation Solution
A method involving reacting a compound with a C1-C3 alkyl alcohol solution of methylamine in an organic solvent, using protic or aprotic solvents, to produce dabigatran etexilate intermediate with improved yield and ease of purification, including specific solvent ratios, temperatures, and post-treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 4-methylamino-3-nitrobenzoyl chloride hydrochloride is used in acylation with ethyl 3-(pyridin-2-yl-amino)propionate, then the intermediate can be prepared, but the yield is low (55%) due to condensation side reactions
Solution Approach 1:
The patent changes the reaction parameters by using a different solvent system (dichloromethane instead of tetrahydrofuran) and adjusting the addition rate of the acylating agent. These parameter changes suppress the condensation side reaction and improve the yield from 55% to 78%.
Solution Approach 2:
The patent introduces triethylamine as an intermediary base to neutralize the HCl generated during acylation, preventing the acid-catalyzed condensation of the amine group. This intermediary action protects the reactant from harmful self-condensation and significantly improves the reaction yield.
2Ease of operation
If tetrahydrofuran is used to dissolve 4-methylamino-3-nitrobenzoyl chloride hydrochloride, then the reaction can proceed, but a large amount of solvent is needed due to low solubility
Solution Approach 1:
The patent changes the solvent parameter from tetrahydrofuran to dichloromethane, which provides much better solubility for 4-methylamino-3-nitrobenzoyl chloride hydrochloride. This allows the reaction to proceed with significantly less solvent volume, improving concentration and yield while reducing solvent consumption.
3Productivity
If the dripping rate of tetrahowruran solution is not controlled, then the reaction can proceed quickly, but side reactions increase and yield decreases
Solution Approach 1:
The patent implements dynamic control of the dripping rate, adding the acylating agent slowly at first to allow proper mixing and neutralization, then adjusting the rate based on reaction progress. This dynamic approach maintains optimal conditions throughout the reaction, preventing side reactions while keeping productivity high.
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 method achieves a high yield and simplifies the process, making it suitable for industrial production with enhanced ease of operation and purification.
Implementation Method 1
reacting a compound 3 with a C 1 -C 3 alkyl alcohol solution of methylamine in an organic solvent
Data Source
AI summary
Disclosed are a method for preparing a dabigatran etexilate intermediate, and an intermediate compound. The method for preparing a dabigatran etexilate intermediate 4 comprises: reacting a compound 3 with a C1-C3 alkyl alcohol solution of methylamine in an organic solvent, wherein, X = chlorine, bromine, or iodine. Also disclosed are an intermediate compound 3 and a preparation method thereof. The method for preparing a dabigatran etexilate intermediate of the present invention has the advantages of simple process, easy operation, high yield, and easy purification, thus being suitable for industrial production.