Lacosamide Resolution Crystallization for High Purity at Lower Cost

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Solution Overview

Problem

Existing methods for producing lacosamide are costly, inefficient, and environmentally unsustainable, with low yield and diastereomeric excess, and require expensive starting materials and reagents, posing safety and environmental risks.

Innovation Solution

A method involving isomerization-crystallization and acetylation processes using specific amino acids and aldehyde compounds at controlled temperatures and solvent amounts to selectively crystallize and acetylate racemic N-benzyl-2-amino-3-methoxypropionamide, optimizing reaction conditions to achieve high diastereomeric excess and chemical purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If expensive D-serine and O-methylation reagents are used, then lacosamide can be produced with high chemical purity, but production cost increases significantly

Engineering Contradiction:
Improvechemical purityVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs inexpensive amino acid derivatives (such as N-acetyl-D-leucine, N-acetyl-D-valine, N-acetyl-D-alanine, or N-acetyl-D-phenylalanine) as resolving agents instead of expensive D-serine and its derivatives. These cheap amino acid derivatives achieve effective resolution of the racemic mixture while significantly reducing production costs. The resolving agents can be easily separated and reused, making them economically viable for industrial production.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical parameters of the resolution process by using amino acid derivatives with different side chains (leucine, valine, alanine, phenylalanine) to optimize the formation of diastereomeric salts. By adjusting the type and amount of resolving agent, the process achieves high chemical purity (95% or more) while maintaining cost-effectiveness. The patent also optimizes reaction conditions such as temperature (0-65°C) and solvent selection to enhance purity without increasing cost.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If dimethyl sulfate is used as O-methylation reagent, then lacosamide can be produced in large scale, but safety and environmental problems arise

Engineering Contradiction:
Improveproduction scaleVSAvoidsafety and environmental impact
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces dimethyl sulfate with safer and environmentally friendly O-methylation reagents such as methyl iodide, silver oxide, or dimethyl carbonate. These alternative reagents achieve the same O-methylation transformation at industrial scale while eliminating the severe safety hazards and environmental pollution associated with dimethyl sulfate. The new reagents can be handled with standard laboratory safety protocols and produce minimal harmful byproducts.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts the potentially harmful methylation process into a safe and environmentally benign transformation by selecting appropriate reagents. Instead of using highly toxic dimethyl sulfate, the process employs reagents that are either less hazardous or can be easily disposed of. The methylation step maintains high productivity while the choice of reagent transforms a harmful process into an environmentally sustainable one, aligning with green chemistry principles.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If racemic lacosamide is generated and resolved, then lacosamide can be produced, but yield and diastereomeric excess are insufficient

Engineering Contradiction:
ImproveyieldVSAvoiddiastereomeric excess
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent optimizes the resolution process by changing the parameters of diastereomeric salt formation. By selecting specific amino acid derivatives as resolving agents and controlling reaction conditions (temperature, solvent type, stoichiometry), the patent achieves high diastereomeric excess (90% or more) while maintaining high yield. The patent demonstrates that by adjusting these parameters, both yield and diastereomeric excess can be simultaneously optimized, overcoming the limitations of conventional resolution methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by using amino acid derivatives with specific chiral environments (different side chains) to create localized chiral interactions that favor the formation of desired diastereomeric salts. The chiral amino acid derivatives provide a localized chiral field that selectively interacts with the racemic lacosamide, enabling effective resolution. This localized chiral recognition achieves high diastereomeric excess while maintaining overall high yield through optimized process conditions.

Inventive Principle:
Principle #3Local quality

4Manufacturing precision

If high reaction temperature is used for diastereomeric salt formation, then resolution can be achieved, but production efficiency decreases

Engineering Contradiction:
Improveresolution effectivenessVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the temperature parameter from high (conventional 85°C or higher) to moderate ranges (0-65°C). By adjusting the temperature to this optimized range and using appropriate amino acid derivatives as resolving agents, the patent achieves effective resolution without the energy consumption and reduced efficiency associated with high-temperature processes. The moderate temperature range maintains reaction effectiveness while significantly improving production efficiency and reducing energy costs.

Inventive Principle:
Principle #35Parameter changes

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 enables the production of lacosamide with high yield, chemical purity, and diastereomeric excess at a lower cost, enhancing industrial safety and environmental sustainability.

Implementation Method 1

an isomerization-crystallization process that causes racemic N-benzyl-2-amino-3-methoxypropionamide to react with at least one selected from a group consisting of N-acetylamino acid selected from the group consisting of N-acetyl-D-leucine, N-acetyl-D-valine, N-acetyl-D-alanine, and N-acetyl-D-phenylalanine, and N-formylamino acid, selected of the group consisting of N-formyl-L-leucine, N-formyl-L-alanine, and N-formyl-L-phenylalanine, in a solvent in the presence of an aldehyde compound at a temperature lower than 65 °C to selectively crystalize a salt of R-configuration of N-benzyl-2-amino-3-methoxypropionamide and N-acetylamino acid or N-formylamino acid

Methodology Applied
Scientific EffectIsomerization:

Implementation Method 2

selectively crystalize a salt of R-configuration of N-benzyl-2-amino-3-methoxypropionamide and N-acetylamino acid or N-formylamino acid

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Implementation Method 3

an acetylation process that acetylates the R-configuration N-benzyl-2-amino-3-methoxypropionamide contained in the salt to obtain lacosamide

Methodology Applied
Scientific EffectAcetylation:

Data Source

PatentEP3375771B1Method for producing lacosamide and intermediate thereof
Publication Date: 2025.11.26 API CORP (JP)
  • EP3375771B1 patent drawingFigure 1
  • EP3375771B1 patent drawingFigure 2
  • EP3375771B1 patent drawingFigure 3

AI summary

The present invention provides a method of industrially and safely producing lacosamide high in diastereomeric excess at a high yield and a low cost. Adopting a particular isomerization-crystallization condition makes it possible to a method of industrially and safely producing lacosamide high in diastereomeric excess at a high yield and a low cost. Additionally, an intermediate efficacious for producing lacosamide is provided.