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Method for preparing 2,3-dichlorotoluene

A dichlorotoluene and o-tolyl-based technology, applied in 2 fields, can solve the problems of inaccessibility of raw materials, high price, long time-consuming and the like of the synthetic route, and achieve the effects of low cost, low price and environmental friendliness

Inactive Publication Date: 2011-06-01
INNER MONGOLIA UNIV OF TECH
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0013] In the above-mentioned report on the synthesis route of 2,3-dichlorotoluene, the raw materials of the synthesis route of C.S. Marvel et al. are not easy to obtain, the price is expensive, and the yield is low; although Deng Hong’s synthesis route starts from the cheap and easy-to-obtain o-toluidine , but a large amount of acetic anhydride is used in the first step to synthesize 3-nitro-2-aminotoluene, the steam distillation process takes a long time, and the yield of this step is only 50%

Method used

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  • Method for preparing 2,3-dichlorotoluene

Examples

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Embodiment 1

[0028] Embodiment 1: Add o-toluidine 43ml, urea 18g, and xylene 170ml in the 500ml round-bottomed three-neck flask that stirring, measuring temperature and reflux device are housed and heat up to 138 ℃, reflux reaction 7 hours, pour out while hot. Then cool to normal temperature under stirring, filter, the filter cake is washed with xylene, drained, and dried, and then washed with a large amount of water, drained, and dried to obtain 42.90 g of white needle crystals, in terms of o-toluidine, N, The yield of N'-di(o-tolyl)urea was 89.40%.

[0029] Pour 67mL of sulfuric acid into a 500mL three-necked flask equipped with a thermometer and an exhaust gas recovery device, weigh 24.00g of N,N'-di(o-tolyl)urea, add it to the solution in batches under stirring, and the addition temperature does not exceed 50°C , after the N,N'-di(o-tolyl)urea was completely dissolved, the temperature was kept at 65° C. for 6 hours, and then the heating was stopped. This gives N,N'-di(o-tolyl)urea-4,4...

Embodiment 2

[0031] Embodiment 2: Weigh 24.00 N, N'-bis(o-tolyl)urea and put it into a 1000ml three-necked flask, pour 10% oleum of 62ml into the dropping funnel, add dropwise and the temperature does not exceed 50°C , dissolve N, N'-bis(o-tolyl)urea, wait until N,N'-bis(o-tolyl)urea is completely dissolved, keep the temperature at 65°C for 6 hours, stop heating. Get N,N'- Bis(o-tolyl)urea-4,4'-disulfonic acid. Add 300ml of water, 160ml of dilute hydrochloric acid and 0.56g of iron powder, pass chlorine gas, keep the heating temperature at 35°C, and react for 12h. To obtain N,N'-bis(2-chloro-6-methylphenyl)urea-4,4'-disulfonic acid, assemble a reflux device, pass nitrogen protection, slowly raise the temperature of the reaction solution to 107°C, and heat-preserve and hydrolyze for 3h Afterwards, the solution was heated to 175° C. in an autoclave. React for 10 hours. After cooling, use sodium carbonate to neutralize to neutrality, then carry out steam distillation, collect the distillat...

Embodiment 3

[0032] Embodiment 3: Weigh 24.00 N, N'-bis(o-tolyl)urea and put it into a 1000ml three-necked flask, pour 67ml of 98% concentrated sulfuric acid into the dropping funnel, add dropwise and the temperature does not exceed 50°C, Dissolve N,N'-di(o-tolyl)urea, wait until N,N'-bis(o-tolyl)urea is completely dissolved, keep the temperature at 65°C for 6 hours, stop heating. Obtain N,N'-di(o-tolyl)urea (o-tolyl)urea-4,4'-disulfonic acid. Add 300ml of water, 160ml of dilute hydrochloric acid and 0.56g of iron powder, pass chlorine gas, keep the heating temperature at 35°C, and react for 12h. To obtain N,N'-bis(2-chloro-6-methylphenyl)urea-4,4'-disulfonic acid, assemble a reflux device, pass nitrogen protection, slowly raise the temperature of the reaction solution to 107°C, and heat-preserve and hydrolyze for 3h Afterwards, the solution was heated to 175° C. in an autoclave. React for 10 hours. After cooling, use sodium carbonate to neutralize to neutrality, then carry out steam di...

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Abstract

The invention discloses a method for preparing 2,3-dichlorotoluene. The method comprises the following steps of: performing condensation on o-toluidine serving as an initiative raw material and urea to obtain N,N'-di(tolyl) urea; forming a sulfonic blocking group at an amino para-position through sulfonation; performing chlorination, removing carbonyl through hydrolysis and removing the blocking group through hydrolysis to obtain 2-chlorine-6-methylaniline; and performing diazotization and a Sandmeyer reaction to synthesize 2,3-dichlorotoluene to obtain the product. The method has the advantages of environmental friendliness, simple process, low cost and the like.

Description

technical field [0001] The invention relates to a method for synthesizing an important intermediate of lamotrigine, in particular to a method for preparing 2,3-dichlorotoluene. Background technique [0002] Lamotrigine (Lamotrigine) is a new type of specific antiepileptic drug, which was created by the British Wellcome Company in 1985, and 2,3-dichlorotoluene is an important intermediate for the synthesis of Lamotrigine. At present, there are more than 50 million epilepsy patients in the world, and the demand for antiepileptic drugs is considerable. In recent decades, the development of new and more efficient antiepileptic drugs has aroused the close attention of drug researchers all over the world. [0003] In the known technology, the synthetic route of 2,3-dichlorotoluene: [0004] 1. Foreign C.S.Marvel et al. proposed the method of synthesizing 2,3-dichlorotoluene: starting from 3-nitro-2-aminotoluene through Sandmeyer reaction to obtain 3-nitro-2-chlorotoluene, and th...

Claims

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Application Information

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IPC IPC(8): C07C25/08C07C17/093
CPCY02P20/584
Inventor 张前程简丽王云崔玲聚明董晔包亚莉
Owner INNER MONGOLIA UNIV OF TECH
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