Method for synthesizing 3-ethylamino-4-methylphenol

A methylphenol, ethylamine-based technology, applied in the field of organic synthesis, can solve problems such as difficult recycling, large safety hazards, and increased difficulty, achieve real-time online detection and analysis, save equipment space, and improve process The effect of R&D efficiency

Active Publication Date: 2021-12-03
上海昕凯医药科技有限公司
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  • Abstract
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Problems solved by technology

[0004] The above catalytic hydrogenation synthesis method is a traditional gas-liquid-solid three-phase heterogeneous reaction. In order to ensure full contact of the three phases, high temperature and high pressure (15 atm) conditions are required, which not only requires high energy consumption, but also requires high pressure reactor equipment. High, there is still a huge safety hazard, plus palladium carbon is expensive, it is difficult to recycle in the reaction solution, the cost is high, and the two-step reaction is more cumbersome, time-consuming and labor-intensive, and the efficiency is low
In addition, in the traditional reactor reaction, the reaction will exotherm violently and produce a large amount of gas when feeding materials, which poses a great safety hazard, which increases the difficulty of process scale-up

Method used

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  • Method for synthesizing 3-ethylamino-4-methylphenol
  • Method for synthesizing 3-ethylamino-4-methylphenol

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Take by weighing 153g 3-nitro-4-methylphenol and 2.55g B (C6F5) 3 be dissolved in 1L tetrahydrofuran and ethanol 1:1 (volume ratio, the following examples are all the same) in the mixed solvent, stir until dissolving clear, then Inject it into the preheating module and preheat it to 10°C; set the palladium carbon loading to 2mL, the particle size to 0.2mm, and the pressure to 5atm, then control the H2 feed flow rate to 20sccm; N2 feed flow rate to 60sccm, Finally, inject the preheated 3-nitro-4-methylphenol solution into the preheated reaction module at a feed flow rate of 0.5 mL / min. Collect the effluent reaction solution (sampling HPLC analysis, raw material 3.3%, main impurity (diethylation) 13.7%, product 82.6%), spin the solvent, and use 350mL petroleum ether / 20mL methyl tert-butyl ether (the ratio of the following examples (all the same) beating for 1 hour, suction filtered to obtain a white solid, and dried to obtain 91 g of product with a yield of 60%, HPLC: 95....

Embodiment 2

[0030] Weigh 153g of 3-nitro-4-methylphenol and 2.55g of B(C6F5)3 and dissolve in 1L of tetrahydrofuran and ethanol 2:1 mixed solvent, stir until dissolved, then inject it into the preheating module and preheat to 25°C; set the loading amount of palladium carbon to 3mL, the particle size to 0.3mm, and the pressure to 5atm, then control the feed flow rate of H2 to 30sccm; the feed flow rate of N2 to 60sccm, and finally preheat the 3-nitro- The 4-methylphenol solution was injected into the preheated reaction module at a feed flow rate of 0.75mL / min. Collect the effluent reaction solution (sample HPLC analysis, raw material 1.1%, main impurity (diethylated) 8.8%, product 89.9%), spin to dry the solvent, beat with petroleum ether / methyl tert-butyl ether mixed solvent for 1h, and suction filter A white solid was obtained, and 108 g of product was obtained by drying, with a yield of 72%, GC / HPLC: 96.5%.

Embodiment 3

[0032] Weigh 153g of 3-nitro-4-methylphenol and 2.55g of B(C6F5)3 and dissolve in 1L of tetrahydrofuran and ethanol 2:1 mixed solvent, stir until dissolved, then inject it into the preheating module and preheat to 40°C; set the loading amount of palladium carbon to 4mL, the particle size to 0.4mm, and the pressure to 5atm, then control the feed flow rate of H2 to 20sccm; the feed flow rate of N2 to 60sccm, and finally preheat the 3-nitro- The 4-methylphenol solution was injected into the preheated reaction module at a feed flow rate of 0.75mL / min. Collect the effluent reaction solution (sample HPLC analysis, raw material 4.9%, main impurity (diethylated) 10.3%, product 84.5%), spin to dry the solvent, beat with petroleum ether / methyl tert-butyl ether mixed solvent for 1h, and suction filter A white solid was obtained, and 110 g of the product was obtained by drying, with a yield of 73%, HPLC: 94.1%.

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Abstract

The invention provides a novel method for synthesizing 3-ethylamino-4-methylphenol, and belongs to the technical field of organic synthesis. The method comprises the following steps: dissolving 3-nitro-4-methylphenol and a Lewis acid catalyst in an ethanol / tetrahydrofuran solvent, adding the solution to a preheating module, preheating to 25-30 DEG C, filling a reactor with a catalyst palladium on carbon, opening a hydrogen feeding valve and a nitrogen feeding valve, controlling the flow rate, adding the preheated 3-nitro-4-methylphenol solution to a reaction module, and carrying out a gas-liquid-solid three-phase reaction to obtain the target compound 3-ethylamino-4-methylphenol. The catalyst used in the method can be recycled, the cost is saved, the reaction condition is mild, the reaction yield is high, the purity is high, the numerical control display operation is simple, and the safety is high.

Description

technical field [0001] The invention relates to the synthesis of active ingredients of cosmetics, in particular to a method for synthesizing 3-ethylamino-4-methylphenol, which belongs to the technical field of organic synthesis. Background technique [0002] 3-Ethylamino-4-methylphenol, CAS: 120-37-6, pale yellow solid. As a care cosmetic, it is effective in preventing hair loss. The operational route of synthesizing 3-ethylamino-4-methylphenol at present is divided into two steps and reacts, and reaction formula is as follows: [0003] [0004] The above catalytic hydrogenation synthesis method is a traditional gas-liquid-solid three-phase heterogeneous reaction. In order to ensure full contact of the three phases, high temperature and high pressure (15 atm) conditions are required, which not only requires high energy consumption, but also requires high pressure reactor equipment. High, there is also a huge safety hazard, plus palladium carbon is expensive, it is diffi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C213/02C07C215/76
CPCC07C213/02C07C215/76Y02P20/584
Inventor 朱亮
Owner 上海昕凯医药科技有限公司
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