Process for the hydrogenation of imines

An imine and hydrogenation technology, applied in organic chemistry methods, chemical instruments and methods, organic chemistry, etc., can solve the problems of low catalyst productivity and inability to achieve complete conversion, etc.

Inactive Publication Date: 2009-02-18
EVONIK DEGUSSA GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In many cases, especially at elevated temperatures (e.g., temperatures >25°C, which are required at short reaction times), complete conversion cannot be achieved
Therefore, the catalyst productivity is too low from an economical production capacity point of view for the industrial application of the hydrogenation process

Method used

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  • Process for the hydrogenation of imines
  • Process for the hydrogenation of imines
  • Process for the hydrogenation of imines

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0172] The following examples illustrate the synthesis of some phosphonium halides (see, Beller et al., Synthesis 2004, 934-941).

[0173] Synthesis of Diadamantylbenzylphosphonium Bromide

[0174] Diadamantylphosphine (10 mmol, 3.02 g) was suspended in 6 ml benzyl bromide and 40 ml dibutyl ether in air. The reaction mixture was stirred at 138 °C for 16 h. After cooling, the solid was filtered, washed with MTBE, and dried. Yield: 4.05 g, 86% (white powder).

Embodiment 2

[0176] Hydrogenation of 2,4,6-trimethyl-N-(4-methylpentan-2-yl (4-methylpentan-2-ylidene))aniline using different phosphonium halides and ligands (for comparison, also carried out To use Bu 4 Some experiments with NI):

[0177] The required additives (0.004-0.006 mmol) were weighed in a 1.5 ml GC-flask under argon (glove box). Then, 300 µl of toluene was added. Subsequently, 50 μl of 0.01 M [Ir(1,5-cyclooctadiene)Cl] in toluene was added 2 solution (0.0005 mmol) and 50 μl of 0.02 M ligand solution (0.001 mmol) in toluene. The mixture was stirred at room temperature for 15 minutes. Then, 250 μl neat substrate or 200 μl 2M or 1M substrate solution in toluene were added. The flask was closed with a septum which was pierced several times with a needle and placed on an aluminum microtiter plate and placed in an autoclave. The autoclave was flushed with hydrogen and 55 bar of hydrogen was introduced. The temperature was set at 65 °C and stirred for 1.75 h. The pressure was r...

Embodiment 3

[0180] The following examples were carried out in a similar manner to Example 2, but with varying ligands, solvents, reaction times, reaction temperatures and / or phosphonium halides:

[0181]

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Abstract

The present invention relates to a process for the hydrogenation of imines with hydrogen in the presence of iridium catalysts. In particular the present invention relates to a process for the hydrogenation of imines with hydrogen under elevated pressure in the presence of an iridium catalysts and with or without an inert solvent, wherein the reaction mixture comprises a phosphonium chloride, bromide or iodide in the presence or in the absence of an acid, which can be an organic or inorganic acid, soluble or insoluble in the reaction mixture. Suitable imines are especially those that contain at least one (Formula I) group. If the groups are substituted asymmetrically and are thus compounds having a prochiral ketimine group, it is possible in the process according to the invention for mixtures of optical isomers or pure optical isomers to be formed if enantioselective or diastereoselective iridium catalysts are used.

Description

technical field [0001] The present invention relates to a process for the hydrogenation of imines with hydrogen under elevated pressure in the presence of an iridium catalyst and a halide, wherein the reaction mixture optionally contains an acid. Background technique [0002] US-A-4 994 615 describes a process for the asymmetric hydrogenation of prochiral N-arylketimines using iridium catalysts with chiral bisphosphine ligands. US-A-5 011 995 describes a process for the asymmetric hydrogenation of prochiral N-alkylketimines using the same catalysts. US-A-5 112999 discloses polynuclear iridium compounds and complex salts of iridium containing bisphosphine ligands as catalysts for the hydrogenation of imines. US-A-5 859 300 describes a process for the asymmetric hydrogenation of prochiral N-alkylketimines in the presence of ammonium halides or metal halides and at least one solid acid which does not comprise an ion exchanger. US-A-5 886 225 describes a process for the asymme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/52C07C211/48
CPCC07C209/52C07B2200/07C07C211/48
Inventor J·阿尔梅纳T·里尔迈尔A·蒙西斯R·卡德罗夫
Owner EVONIK DEGUSSA GMBH
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