Organometallic Catalyst for Safe Reductive Amination
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Solution Overview
Problem
Current methods for preparing amine compounds through reductive amination reactions face challenges such as safety concerns, operability issues, toxicity of reagents, limited solvent compatibility, and low catalyst activity, particularly when using hydrogenation reactions or boron-based reagents, which hinder industrial application and efficiency.
Innovation Solution
Development of ruthenium, rhodium, and iridium complexes with nitrogen-containing ligands as catalysts for reductive amination reactions, which provide high activity and selectivity, enabling efficient production of amine compounds without the need for high-pressure reactors or toxic reagents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogenation reaction using solid catalysts is used, then amine compounds can be prepared, but safety and operability deteriorate due to requirement of pressure-resistant reactor and inability to handle substrates with multiple bonds
Solution Approach 1:
The patent changes the physical state of the catalyst from heterogeneous (solid) to homogeneous (soluble metal complex), and changes the hydrogen source from gaseous hydrogen to liquid/solid organic hydrogen donors. This parameter change eliminates the need for high-pressure equipment while maintaining catalytic activity, directly resolving the contradiction between productivity and ease of operation.
2Ease of operation
If boron reactants are used, then pressure-resistant reactor is not required, but economical and environmental performance deteriorate due to non-catalytic nature
Solution Approach 1:
The patent merges the advantages of two different approaches: it combines the safe, low-pressure operability of boron-based methods with the catalytic efficiency of metal complexes. The soluble metal complex acts as a true catalyst that can be used in small amounts and regenerated, while the reaction proceeds under mild conditions without requiring pressure-resistant equipment, thus resolving the contradiction between ease of operation and productivity.
3Productivity
If NaBH3CN is used, then reductive amination can proceed, but industrial utilization deteriorates due to toxicity
Solution Approach 1:
The patent replaces the toxic but effective NaBH3CN with organic hydrogen donors that are less toxic and more environmentally friendly. These hydrogen donors (such as isopropanol, formic acid, or their derivatives) can be used in catalytic amounts with the metal complex, and their byproducts are generally water or carbon dioxide, eliminating the toxicity issue while maintaining reaction efficiency.
4Productivity
If NaBH(OAc)3 is used, then reductive amination can proceed, but solvent selection and reagent用量 deteriorate due to solubility limitations and single hydride source
Solution Approach 1:
The patent employs a soluble metal complex catalyst that is highly versatile and can operate in a wide range of solvents including water, alcohols, and organic solvents. The catalyst system is designed to be universally applicable to various substrates and can tolerate diverse functional groups, eliminating the solvent selection limitations associated with NaBH(OAc)3 and enabling broader applicability.
5Productivity
If pyridine borane is used, then reductive amination can proceed, but storage stability deteriorates due to decomposition at 54°C or more
Solution Approach 1:
The patent introduces a stable soluble metal complex as an intermediary catalyst that mediates the reductive amination reaction. Instead of using unstable pyridine borane directly, the metal complex facilitates the reaction between the carbonyl compound and amine using stable organic hydrogen donors. This intermediary approach allows the reaction to proceed efficiently while avoiding the storage stability issues of pyridine borane.
6Stability of the object's composition
If 2-picoline borane is used, then storage stability improves compared to pyridine borane, but handling deteriorates due to low melting point of 44-45°C
Solution Approach 1:
The patent replaces 2-picoline borane with stable organic hydrogen donors such as isopropanol, formic acid, or their derivatives that are solids or liquids with convenient handling properties. These hydrogen donors are used in the presence of the soluble metal complex catalyst, providing both the necessary stability and ease of handling while maintaining reaction efficiency.
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 use of these organometallic complexes as catalysts facilitates the efficient and selective production of amine compounds, improving operational safety, reducing environmental impact, and enhancing industrial applicability by eliminating the need for hazardous materials and high-pressure conditions.
Implementation Method 1
a method by means of reductive amination reaction of carbonyl compound and amine compound under the presence of a catalyst
Data Source
AI summary
[Problem]The present invention aims to provide a novel organometallic compound that can be used as a general-use highly active catalyst with superior selectivity for functional groups.[Means for Solving Problem]The present invention relates to an organometallic compound having a novel specific structure of general formula (1):and to a general-use highly active catalyst used in reductive amination reaction with superior selectivity for functional groups that comprises said organometallic compound, and to a process for preparing amine compounds by reductive amination reaction using said catalyst.