Synthetic method of topramezone intermediate 1,2-dimethyl-3-methylsulfanyl-benzene

A kind of technology of dimethyl anisole and oxaflutole

Active Publication Date: 2019-12-03
JIANGSU FLAG CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method has a high yield and is easy to operate, but it is difficult to deal with the "three wastes" produced, the price of raw materials is high, and the solvent has a variety of side reactions in addition to participating in th...

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  • Synthetic method of topramezone intermediate 1,2-dimethyl-3-methylsulfanyl-benzene
  • Synthetic method of topramezone intermediate 1,2-dimethyl-3-methylsulfanyl-benzene

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Embodiment 1

[0024] (1) Put 300g of 10%wt hydrochloric acid into a 500mL four-necked bottle; add 50g (0.41mol) of 2,3-dimethylaniline dropwise while stirring, and solids will precipitate during the dropwise addition; heat up to about 50°C and stir after dropping 30 minutes. Cool the reaction solution to -5°C~0°C, add dropwise sodium nitrite aqueous solution (29g sodium nitrite dissolved in 50g water) (0.42mol), and control the dropwise reaction temperature between -5°C~0°C. After the dropwise addition, keep stirring at -5°C to 0°C for 1 hour to obtain a diazonium salt solution.

[0025] (2) Add 433.2g (1.24mol) of 20% sodium methyl mercaptide aqueous solution to another 1L four-necked bottle, control it not to exceed 35°C, add the above-mentioned diazonium salt solution dropwise, and drop it for about 1 hour; continue to keep warm and stir after dropping Reaction 1h.

[0026] (3) Post-treatment: add dropwise 30% hydrochloric acid to adjust the pH of the reaction solution to about 6, let ...

Embodiment 2

[0028] (1) Put 200g of 20%wt sulfuric acid into a 1L four-necked bottle; add 50g (0.41mol) of 2,3-dimethylaniline dropwise while stirring, and solids will precipitate during the dropping process; heat up to about 50°C and stir after dropping 30 minutes. Cool the reaction solution to -10°C ~ -5°C, add dropwise sodium nitrite aqueous solution (56.6g sodium nitrite dissolved in 100g water) (0.82mol), control the dropwise reaction temperature between -10°C ~ -5°C ; After the dropwise addition, keep stirring at -10°C to -5°C for 1 hour to obtain a diazonium salt solution.

[0029] (2) Add 881.5 g (2.05 mol) of 20% potassium methyl mercaptide aqueous solution to another 2L four-necked bottle, control the reaction temperature at 20-35°C, add the above-mentioned diazonium salt solution dropwise, and finish dropping in about 2 hours; Continue to insulate and stir the reaction for 2h.

[0030] (3) Post-treatment: add dropwise 30% hydrochloric acid to adjust the pH of the reaction solu...

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Abstract

The invention relates to the field of organic synthesis, in particular to a synthetic method of a topramezone intermediate 1,2-dimethyl-3-methylsulfanyl-benzene. The method comprises the following steps: (1) reacting 2,3-dimethylaniline or a salt thereof with sodium nitrite in an acidic environment to generate a corresponding diazonium salt; and (2) reacting the diazonium salt with a methyl mercaptide to generate the 1,2-dimethyl-3-methylsulfanyl-benzene. The synthetic method of the topramezone intermediate 1,2-dimethyl-3-methylsulfanyl-benzene provided by the invention has low costs and lessthree wastes (waste gas, waste water and industrial residue), uses the sodium nitrite to replace expensive nitrous acid ester, uses the methyl mercaptide to replace dimethyl sulfide with a strong smell, has good atom economy, avoids generation of methyl mercaptide with a smell difficult to control, and avoids the problems of solvent recovery and environmental problems in the recovery process caused by the use of a large amount of the dimethyl sulfide.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for synthesizing 2,3-dimethylanisole, an intermediate of fenflumezone. Background technique [0002] The English name of 2,3-dimethylanisole sulfide is 1,2-Dimethyl-3-methylsulfanyl-benzene, which is an important intermediate for the synthesis of the corn post-emergence herbicide oxentrazone, and is also used in the synthesis of other pesticides and medicines . The reported synthetic methods can be divided into 2,3-dimethylbromobenzene method and 2,3-dimethylaniline method according to the raw materials. [0003] Journal of Organic Chemistry, 2010, 75(3): 660-665 reported that 2,3-dimethylbromobenzene was prepared as Grignard reagent, and then reacted with dimethyl disulfide to obtain 2,3-dimethylbenzylsulfide Ether, yield 96%. The method has a high yield, but the raw materials are not easy to obtain, the reaction conditions are harsh, the reaction process is dangerou...

Claims

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Application Information

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IPC IPC(8): C07C319/14C07C321/28C07C245/20
CPCC07C245/20C07C319/14C07C321/28
Inventor 卜龙张璞钱梓伟侯远昌王凤云
Owner JIANGSU FLAG CHEM IND
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