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Process for preparing 4-amino-N, N-dimethylbenzylamine

A technology of dimethylbenzylamine and dimethylamine, which is applied in the field of preparation of 4-amino-N,N-dimethylbenzylamine, can solve the problems of low yield, large pollution, long reaction time, etc. Ease of implementation, optimized reaction conditions, high purity and yield

Active Publication Date: 2014-05-07
ZHEJIANG HISOAR PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] It can be seen that the existing preparation methods all have deficiencies: the reaction time is long and the yield is low; the purification by column chromatography cannot meet the needs of industrialization; the catalytic hydrogenation reduction of precious metals is costly and requires special equipment; the use of stannous chloride for reduction Or iron powder reduction, large pollution, difficult post-processing

Method used

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  • Process for preparing 4-amino-N, N-dimethylbenzylamine
  • Process for preparing 4-amino-N, N-dimethylbenzylamine
  • Process for preparing 4-amino-N, N-dimethylbenzylamine

Examples

Experimental program
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Effect test

Embodiment 1

[0052] In a 500mL four-necked flask, add 150mL of chloroform without water, 32g (0.379 moles) of dimethylamine hydrochloride, stir, cool to 5°C, add 59g (0.584 moles) of triethylamine dropwise, and then every 10 minutes Add 5.7g, 5.3g, 4.9g, 4.5g, 4.1g, 3.8g, 3.5g, 3.2g, 1.0g of p-nitrobenzyl bromide in batches to ensure the single batch feeding amount of p-nitrobenzyl bromide in the reaction system The mole percentage of dimethylamine in the reaction system is less than 7%, and 36g (0.167 mole) of p-nitrobenzyl bromide is added. The temperature was controlled at 15°C, and the reaction was completed after stirring for 2 hours after the addition. The GC content of 4-nitro-N,N-dimethylbenzylamine is 98.3%, and the impurity A is 1.5%. Add 150 mL of water, stir and separate layers, remove the water phase, wash the organic phase with water, concentrate to dry the solvent, add 100 mL of n-heptane to the residue, cool at -20°C for 6 hours, filter, remove the filter cake, and distill...

Embodiment 2

[0057] In a 500mL four-necked flask, add 150mL of chloroform without water, 32g (0.379 moles) of dimethylamine hydrochloride, stir, cool to 5°C, add 59g (0.584 moles) of triethylamine dropwise, and then every 10 minutes Add p-nitrobenzyl bromide 3.2g, 3.0g, 2.8g, 2.6g, 2.4g, 2.3g, 2.2g, 2.1g, 2.0g, 1.9g, 1.8g, 1.7g, 1.6g, 1.5g, 1.4g, 1.3g, 1.2g, 1.0g, to ensure that the single batch of p-nitrobenzyl bromide in the reaction system and the molar percentage of dimethylamine in the reaction system are all less than 4%, add 36g of p-nitrobenzyl bromide altogether (0.167 mol). The temperature was controlled at 15°C, and the reaction was completed after stirring for 2 hours after the addition. The GC content of 4-nitro-N,N-dimethylbenzylamine is 99.3%, and the impurity A is 0.5%. Add 150 mL of water, stir and separate layers, remove the water phase, wash the organic phase with water, concentrate to dry the solvent, add 100 mL of n-heptane to the residue, cool at -20°C for 6 hours, ...

Embodiment 3

[0062] In a 500mL four-neck flask, add 150mL of chloroform without water, 34g (0.402 moles) of dimethylamine hydrochloride, stir, cool to 5°C, add dropwise 50g (0.494 moles) of triethylamine, and then drop in 3 hours Add a solution of 36 g (0.167 moles) of p-nitrobenzyl bromide dissolved in 100 mL of chloroform, control the temperature of the reaction system at 15° C., and stir for 2 hours after the addition. After the reaction is complete, add 150 mL of water, stir and separate the layers, remove the water phase, wash the organic phase with water, concentrate to dry the solvent, add 100 mL of n-heptane to the residue, cool at -20°C for 6 hours, filter, remove the filter cake, and distill the filtrate to remove the solvent. 28.8 g of 4-nitro-N,N-dimethylbenzylamine was obtained, the yield was 96%, the GC content was 99.8%, and impurity A was not detected.

[0063] 1 H-NMR data: 1 H-NMR (400MHz, CDCl 3 )δ:2.26(6H,s),3.51(2H,s),7.49(2H,d,J=9.0Hz),8.18(2H,d,J=8.7Hz)

[0064] ...

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Abstract

The invention provides a process for preparing 4-amino-N,N-dimethylbenzylamine. The process comprises the steps of: (1) adding solutions of 4-nitro benzyl bromide or 4-nitro benzyl bromide in an organic solvent in batches into an organic solvent containing dimethylamine and triethylamine to obtain 4-nitryl-N,N-dimethylbenzylamine, wherein the single batch feeding amount of 4-nitro benzyl bromide and the molar percentage of dimethylamine in the reaction system are smaller than 7 percent; (2) reducing 4-nityl-N,N-dimethylbenzylamine by using a reducing agent to obtain 4-amino-N,N-dimethylbenzylamine. According to the process, the side reaction mechanism and the effective control method of a new impurity bis(nitrobenzyl)-dimethyl ammonium bromide are studied, the reaction conditions are optimized, the entire process is simple and easily implemented, and the purity and yield of the product are high; and the process is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of organic chemical synthesis, and in particular relates to a preparation method of 4-amino-N,N-dimethylbenzylamine. Background technique [0002] 4-Amino-N,N-dimethylbenzylamine is an important compound. As an intermediate of dyes, pesticides or medicines, it requires high purity and can be produced industrially. Its structural formula is as follows: [0003] [0004] About the preparation method of 4-amino-N,N-dimethylbenzylamine, existing literature reports have: [0005] US5852030A discloses that 4-nitro-N,N-dimethylbenzylamine is reduced in methanol through platinum hydroxide catalytic hydrogenation or in ethanol through stannous chloride reduction to obtain 4-amino-N,N-dimethyl benzylamine. [0006] US6166006A discloses: adding an aqueous solution of dimethylamine to a tetrahydrofuran solution of p-nitrobenzyl bromide at 0°C, reacting for 60 hours, and purifying by column chromatography to obtain 4-nitro-N...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C211/49C07C209/36
Inventor 唐方辉张群辉王晓艳叶彬彬孙常磊陈文斌
Owner ZHEJIANG HISOAR PHARMA
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