Application of a dinuclear rhodium complex in n-methylation reaction of aliphatic amines

A technology of rhodium complexes and aliphatic amines is applied in the application field of binuclear semi-sandwich trivalent rhodium complexes in N-methylation reaction of aliphatic amines, and can solve the problems of high requirements on reaction equipment, harsh reaction conditions, limited application and the like , to achieve the effect of less demanding reaction equipment, mild reaction conditions and high catalytic activity

Active Publication Date: 2021-12-07
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the method of halogenated hydrocarbons as alkylating reagents is that the nitrogen negative ion intermediate formed by the substrate and strong base (sodium tert-butoxide or butyllithium, etc. air-sensitive reagents) at low temperature carries out nucleophilic attack on halogenated hydrocarbons. , to generate alkane-substituted products, but this method has harsh reaction conditions, complex operations, and high requirements for reaction equipment; sulfuric acid esters (such as dimethyl sulfate, diethyl sulfate, etc.) are a class of active alkyl groups. Alkylation reagent can carry out alkylation reaction under milder conditions, but its toxicity is relatively high, and it is carcinogenic, thus limiting its application in industry

Method used

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  • Application of a dinuclear rhodium complex in n-methylation reaction of aliphatic amines
  • Application of a dinuclear rhodium complex in n-methylation reaction of aliphatic amines
  • Application of a dinuclear rhodium complex in n-methylation reaction of aliphatic amines

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Synthesis of the binuclear semi-sandwich rhodium complex Rh containing ortho-carborane:

[0034]

[0035] At -78°C, n-BuLi (1.6M) in n-hexane (1.00 mL, 1.6 mmol) was slowly added dropwise to the o-C 2 B 10 h 10 (92.0 mg, 0.64 mmol) in tetrahydrofuran solution, stirred at this temperature for 30 minutes, slowly rose to room temperature and continued to react for 30 minutes, then added Se (50.5 mg, 0.64 mmol), and continued to react at room temperature for 1 hour. Then the binuclear rhodium compound [Cp*RhCl 2 ] 2 (256.0 mg, 0.32 mmol) was added to the reaction system for an additional 3 hours. After the reaction was finished, stand and filter, and dry the solvent under reduced pressure. The crude product obtained was separated by column chromatography (petroleum ether / dichloromethane=6:1) to obtain the dark red target product rhodium complex Rh (257.1 mg, produced rate 81%).

[0036] 1 H NMR (400MHz, CDCl 3 ,25℃): δ=4.23(s,2H),1.69(s,30H,Cp*).Theoretical value...

Embodiment 2

[0038] Rh catalyzes N-methylation of aliphatic amines:

[0039]

[0040] The rhodium complex Rh prepared in Example 1 was used as a catalyst to catalyze the N-methylation reaction of aliphatic amines: to ethylamine (10mmol, 0.45g) and CH 3 Add the toluene solution of the binuclear semi-sandwich rhodium complex (0.01mmol, 9.9mg) containing ortho-carborane in I (10mmol, 1.42g), the reaction temperature is room temperature, and the reaction time is 60 minutes, and the concentrated reaction solution after finishing is directly Separation by silica gel column chromatography, drying to constant mass, to obtain the corresponding N-methylated product C 3 h 9 N (91% yield), 1 H NMR (400MHz, CDCl 3 , 25°C): δ=4.63 (brs, 1H), 2.65-2.56 (m, 2H), 2.50 (s, 3H), 1.36 (t, J=7.6Hz, 3H). Elemental analysis: C 60.96, H 15.35, N 23.70 (theoretical); C 60.90, H 15.31, N 23.73 (actual).

Embodiment 3

[0042] Rh catalyzes N-methylation of aliphatic amines:

[0043]

[0044] The rhodium complex Rh prepared in Example 1 was used as a catalyst to catalyze the N-methylation reaction of aliphatic amines: to n-propylamine (10mmol, 0.59g) and CH 3 Add the toluene solution of the binuclear semi-sandwich rhodium complex (0.01mmol, 9.9mg) containing ortho-carborane in I (10mmol, 1.42g), the reaction temperature is room temperature, and the reaction time is 60 minutes, and the concentrated reaction solution after finishing is directly Separation by silica gel column chromatography, drying to constant mass, to obtain the corresponding N-methylated product C 4 h11 N (yield 95%), 1 H NMR (400MHz, CDCl 3 ,25℃):δ=4.63(brs,1H),2.65-2.56(m,2H),2.50(s,3H),1.42-1.38(m,2H),1.20(t,J=7.0Hz,3H) . Elemental analysis: C 65.69, H 15.16, N 19.15 (theoretical); C 65.72, H 15.20, N 19.19 (actual).

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Abstract

The present invention relates to the application of a kind of binuclear rhodium complex in fatty amine N-methylation reaction, with binuclear rhodium complex as catalyst, with CH 3 I, as a methylating agent, catalyzes the N-methylation reaction of fatty amines in an organic solvent to prepare N-methylated derivatives of fatty amines. Compared with the prior art, the binuclear rhodium complex in the present invention has higher catalytic activity at room temperature, and can be used to catalyze the N-methylation reaction of fatty amines to prepare N-methylated derivatives of fatty amines, and the catalytic reaction The yield is high (90‑97%), the reaction conditions are mild, no strong base is required, all reagents are stable to air and water, the requirements for reaction equipment are not high, and there is a wide range of industrial application prospects.

Description

technical field [0001] The invention belongs to the technical field of synthetic chemistry and relates to the application of a dinuclear semi-sandwich trivalent rhodium complex containing an ortho carborane structure in the N-methylation reaction of aliphatic amines. Background technique [0002] Nitrogen-containing compounds are very important intermediates in organic synthesis, and the alkylation reaction of nitrogen atoms in N-H-containing compounds is an important way to synthesize such compounds. The most commonly used alkylating reagents for the alkylation reaction of nitrogen atoms in N-H-containing compounds are halogenated hydrocarbons and sulfuric acid esters. Among them, the method of using halogenated hydrocarbons as alkylating reagents is to carry out nucleophilic attack on halogenated hydrocarbons by the nitrogen negative ion intermediate formed by the substrate and strong base (sodium tert-butoxide or butyllithium, etc. to air-sensitive reagents) at low temper...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J31/22C07C211/08C07C209/08
CPCB01J31/2295B01J2531/0225B01J2531/0238B01J2531/822C07C209/08C07C211/08
Inventor 姚子健李荣建吕文瑞高永红邓维
Owner SHANGHAI INST OF TECH
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