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N-methylation method of aromatic amine

A technology for the methylation of aromatic amines, applied in the field of methylation of amines, can solve the problems of poor reactivity and low yield of N-monomethyl products, and achieve the effect of simple operation and wide application range of substrates

Inactive Publication Date: 2013-09-11
SHAANXI NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this reaction condition is not good for other aniline compounds with substituents, and the yield of N-monomethyl product is extremely low

Method used

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  • N-methylation method of aromatic amine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Preparation of N,N-dimethyl-p-methoxyaniline with the following structural formula

[0014]

[0015] Add 123mg (1mmol) of p-methoxyaniline, 3mL of dimethyl sulfoxide, 0.75mL (20mmol) of formic acid, and 2.78mL (20mmol) of triethylamine into a thick-walled pressure-resistant tube. Gas, sealed thick-walled pressure tube, stirred at 150°C for 12 hours, cooled to room temperature, adjusted the pH value of the reaction solution to alkaline with saturated aqueous sodium hydroxide solution, extracted with dichloromethane (5×3mL), and used Dry over sodium sulfate, remove dichloromethane by distillation under reduced pressure, use a mixture of petroleum ether and ethyl acetate with a volume ratio of 50:1 as eluent, separate the product by flash column chromatography, and prepare N,N-dichloromethane Methyl p-methoxyaniline, its productive rate is 92%, and the characterization data of product are: 1 H NMR (400MHz, CDCl 3 )δ(ppm):6.85(d,J=9.1Hz,2H),6.76(d,J=9.1Hz,2H),3.77(s,3H...

Embodiment 2

[0017] Preparation of N,N-dimethyl-p-chloroaniline with the following structural formula

[0018]

[0019] Add 127mg (1mmol) of p-chloroaniline, 3mL of dimethyl sulfoxide, 0.68mL (18mmol) of formic acid, and 2.50mL (18mmol) of triethylamine into a thick-walled pressure-resistant tube, and bubble with argon for 15 minutes, blowing argon, Seal the thick-walled pressure-resistant tube, stir at 150°C for 12 hours, cool to room temperature, adjust the pH value of the reaction solution to alkaline with saturated aqueous sodium hydroxide solution, extract with dichloromethane (5×3mL), and use anhydrous sulfuric acid for the organic phase Sodium drying, vacuum distillation to remove dichloromethane, the volume ratio of petroleum ether and ethyl acetate is 400:1 mixed solution as eluent, flash column chromatography to separate the product, and prepare N,N-dimethyl p-Chloroaniline, its productive rate is 89%, and the characterization data of product are: 1 H NMR (400MHz, CDCl 3 )δ(...

Embodiment 3

[0021] Preparation of N,N-dimethyl-3,4-dimethylaniline with the following structural formula

[0022]

[0023] Add 121mg (1mmol) of 3,4-dimethylaniline, 3mL of dimethyl sulfoxide, 0.83mL (22mmol) of formic acid, and 3.06mL (22mmol) of triethylamine into a thick-walled pressure-resistant tube, and bubble with argon for 15 minutes , blow argon, seal the thick-walled pressure tube, stir at 140°C for 24 hours, cool to room temperature, adjust the pH value of the reaction solution to alkaline with saturated aqueous sodium hydroxide solution, extract with dichloromethane (5×3mL), organic The phase was dried with anhydrous sodium sulfate, dichloromethane was removed by distillation under reduced pressure, and the mixed solution with a volume ratio of petroleum ether and ethyl acetate of 300:1 was used as an eluent, and the product was separated by flash column chromatography to prepare N, N-dimethyl-3,4-dimethylaniline, its productive rate is 88%, and the characteristic data of pr...

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Abstract

The invention discloses an N-methylation method of an aromatic amine. The method comprises following steps: under protection of inert gas, taking dimethylsulfoxide as a solvent; subjecting the aromatic amine, formic acid and triethylamine to reaction with a mole ratio of 1:15-25:15-25; and then the N-methylated aromatic amine is obtained. Advantages are that: operation is simple, the method can be used for substrates of a wide range, the N-methylated aromatic amine can be obtained with high yield in the absence of catalysts, and the method is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of methylation of amines, and in particular relates to a method for generating N-methylated aromatic amines from aromatic amines under the condition of no catalyst. Background technique [0002] N-methylated aromatic amines are important intermediates in the synthesis of dyes, pharmaceuticals and agrochemicals, as well as some fine chemicals, such as vanillin and Michler's ketone. These compounds are also used as solvents and additives in the synthesis of rubber. [0003] At present, various methylating reagents and catalysts have been mentioned in the literature on the synthesis of N-methylated aromatic amines. For example, methylating reagents include formaldehyde, methyl iodide, methanol, dimethyl sulfate, dimethyl carbonate etc., dimethyl carbonate is commonly used because it has the advantages of environmental protection, non-toxic and harmless, and no waste generation compared with other reagents. In...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C217/84C07C213/08C07C211/52C07C211/48C07C209/68C07D215/06C07D215/12C07D209/08
Inventor 王超姜雪魏雅雯薛东肖建良
Owner SHAANXI NORMAL UNIV
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