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Preparation method of 3-chlorine-2-nitrotoluene

A technology of nitrotoluene and dichloronitrobenzene, which is applied in the field of preparation of 3-chloro-2-nitrotoluene, can solve the problems of complex post-processing and large acid content, and achieve reduced energy consumption, reduced side reactions, speed-up effect

Inactive Publication Date: 2011-08-03
SHANGHAI INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] People such as Tianjin University Chen Lei once studied the latter two-step reaction, and the second step hydrochloric acid: acetic acid: the mol ratio of 2-cyano-2-(3-chloro-2-nitrophenyl) methyl acetate is 80: 40:1 heating and hydrolysis decarboxylation to produce 3-chloro-2-nitrophenylacetic acid, the amount of acid required for the reaction is relatively large, and the post-treatment is complicated

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Step (1): In a 500mL three-necked flask, add 46.5g (0.24mol) 2,6-dichloronitrobenzene and 36.1g (0.25mol) tert-butyl cyanoacetate, 69.0g (0.50mol) potassium carbonate, 200mLN , N-dimethylformamide as a solvent, stirring and heating to 90-100°C for 8 hours; stop the reaction, naturally cool to room temperature, under 30mmHg, remove N, N-dimethylformamide under reduced pressure, and naturally cool to At room temperature, pour into 500mL of ice water, add dropwise hydrochloric acid solution with a mass fraction of 10% under stirring until the pH value is 3, wait for the solid to be fully separated, filter with suction, and recrystallize the filter cake with petroleum ether and ethyl acetate to obtain 62.9g of Yellow solid, yield 88.5%.

[0018] Step (2): In a 250mL three-necked flask, add 10g (0.03mol) of tert-butyl 2-cyano-2-(3-chloro-2-nitro)phenylacetate, add 25mL (0.8mol) of concentrated hydrochloric acid and ice Acetic acid 34mL (0.6mol), reflux for 2h. After the re...

Embodiment 2

[0021] Step (1): In a 500mL three-necked flask, add 46.5g (0.24mol) 2,6-dichloronitrobenzene and 35.2g (0.25mol) tert-butyl cyanoacetate, 69.0g (0.50mol) potassium carbonate, 250mL N,N-dimethylformamide is used as a solvent, stir and heat up to 80-90°C for 6 hours; stop the reaction, cool to room temperature naturally, under 30mmHg, remove N,N-dimethylformamide under reduced pressure, then cool naturally to room temperature, pour it into 400mL of ice water, add dropwise a 10% hydrochloric acid solution with mass fraction until the pH value is 4, wait for the solid to fully separate out, filter with suction, and recrystallize the filter cake with petroleum ether and ethyl acetate to obtain 53.3g Pale yellow solid, yield 74.9%.

[0022] Step (2): In a 250mL three-necked flask, add 10g (0.03mol) of tert-butyl 2-cyano-2-(3-chloro-2-nitro)phenylacetate, add 25mL (0.8mol) of concentrated hydrochloric acid and ice Acetic acid 28.3mL (0.5mol), reflux for 5h. After the reaction stopp...

Embodiment 3

[0025] Step (1): In a 250mL three-necked flask, add 19.2g (0.1mol) 2,6-dichloronitrobenzene and 15.5g (0.11mol) tert-butyl cyanoacetate, 27.6g (0.20mol) potassium carbonate, 70mL N,N-dimethylformamide is used as a solvent, stir and heat up to 100-110°C for 8 hours; stop the reaction, cool to room temperature naturally, under 30mmHg, remove N,N-dimethylformamide under reduced pressure, and then cool naturally to room temperature, poured into 200mL of ice water, and added dropwise hydrochloric acid solution with a mass fraction of 10% until the pH value was 3.5 under stirring. Yellow solid, yield 91.5%.

[0026] Step (2): In a 250mL three-necked flask, add 10g (0.03mol) of tert-butyl 2-cyano-2-(3-chloro-2-nitro)phenylacetate, 20mL (0.64mol) of concentrated hydrochloric acid and ice Acetic acid 34mL (0.6mol), reflux for 6h. After the reaction was stopped, it was cooled to room temperature, and the solid was fully separated out, and filtered with suction to obtain 6.2 g of white...

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Abstract

The invention discloses a method for preparing 3-chlorine-2-nitrotoluene, which comprises: taking N,N-dimethylformamide as a solvent, and making 2,6-dichloronitrobenzene react with cyanoacetic acid tert-butyl ester under the action of potassium carbonate; removing the solvent at reduced pressure after the reaction is over, pouring a residual liquid into ice water, and performing suction filtration when solid is fully separated out; using petroleum ether and ethyl acetate to recrystallize filter cakes, and obtaining crystals, namely 2-cyano-2-(3-chlorine-2-nitrobenzophenone)tert-butyl acetate; performing heating reflux on the obtained crystals and hydrochloric acid and acetic acid, cooling and pouring the mixture into water, performing suction filtration after solid is fully separated out, and obtaining 3-chlorine-2-nitrophenyl-acetic acid; performing stirring and heating reaction on the 3-chlorine-2-nitrophenyl-acetic acid, the potassium carbonate and the solvent N,N-dimethylformamide for 0.5 to 4 hours, and reclaiming the N,N-dimethylformamide through reduced pressure distillation; and pouring a residual liquid into water, using trichloromethane for extraction, fully removing the trichloromethane, and obtaining solid, namely the 3-chlorine-2-nitrotoluene. The preparation method has low energy consumption, small number of byproducts and high reaction yield, and the total yield of the 3-chlorine-2-nitrotoluene is more than 80 percent.

Description

technical field [0001] The invention relates to a preparation method of nitro compounds, in particular to a preparation method of 3-chloro-2-nitrotoluene. Background technique [0002] 3-Chloro-2-nitrotoluene can be used as intermediates of nipyrrolicin, its analogues 7-indole carboxylic acid and quinoxaline-zengrin, etc., and has extremely wide uses. In recent years, it has been reported that it is used to prepare new cardiovascular drugs, making its development prospect more broad. At present, this compound mainly depends on imports in China, which is expensive. The synthetic method of existing 3-chloro-2-nitrotoluene is as follows: [0003] 1) Using 2,6-dichloroaniline as a raw material, 2-cyano-2-(3'-chloro-2'-nitrophenyl)methyl acetate was prepared through diazotization, substitution reaction and condensation reaction. [0004] 2) 3-Chloro-2-nitrophenylacetic acid was obtained by hydrolysis and decarboxylation of methyl 2-cyano-2-(3'-chloro-2'-nitrophenyl)acetate. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C205/12C07C201/12
Inventor 杜葩
Owner SHANGHAI INST OF TECH