CN110305010B - Preparation method of 2, 5-dimethylphenylacetic acid - Google Patents
Preparation method of 2, 5-dimethylphenylacetic acid Download PDFInfo
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- CN110305010B CN110305010B CN201910644785.9A CN201910644785A CN110305010B CN 110305010 B CN110305010 B CN 110305010B CN 201910644785 A CN201910644785 A CN 201910644785A CN 110305010 B CN110305010 B CN 110305010B
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- dimethylbenzyl
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/15—Preparation of carboxylic acids or their salts, halides or anhydrides by reaction of organic compounds with carbon dioxide, e.g. Kolbe-Schmitt synthesis
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F3/00—Compounds containing elements of Groups 2 or 12 of the Periodic System
- C07F3/02—Magnesium compounds
Abstract
The invention relates to the field of organic synthesis, in particular to a method for synthesizing 2, 5-dimethylphenyl acetic acid, which comprises the following steps: 2, 5-dimethylbenzyl halide reacts with magnesium to generate Grignard reagent 2, 5-dimethylbenzyl magnesium halide; 2, 5-dimethyl benzyl magnesium halide reacts with carbon dioxide to generate 2, 5-dimethyl phenylacetic acid. The invention has the advantages that the use of expensive noble metal catalyst and/or virulent cyaniding reagent is avoided in the synthetic process of the 2, 5-dimethylphenylacetic acid, the used reagent is environment-friendly, the cost is reduced, the process is simplified, the reaction steps are shortened, the yield is higher, the defects of the prior art are overcome, and the method is suitable for large-scale industrial production.
Description
Technical Field
The invention relates to the field of organic synthesis, in particular to a preparation method of 2, 5-dimethylphenylacetic acid.
Background
2, 5-dimethyl phenylacetic acid is an important fine chemical intermediate, which is widely applied to the fields of medicines and pesticides, in particular, is a key intermediate of a novel pesticide spirotetramat, and the pesticide is the only pesticide with bidirectional systemic conductivity so far.
Regarding the synthesis technology of 2, 5-dimethylphenylacetic acid, the following methods are mainly available in reference to domestic and foreign documents:
1.2, 5-dimethylbenzyl chloride was used as a starting material in Bulletin of the Chemical Society of Japan 1975,48(2),497-504 by Kazuhiko et al, and 2, 5-dimethylbenzyl acetic acid was synthesized by a two-step reaction of cyanation and hydrolysis in the following reaction scheme. The method has the advantages of 38 percent of total yield in three steps, lower yield and extremely toxic cyaniding reagent.
2. A synthesis method of 2, 5-dimethylphenylacetic acid disclosed in bayer patent CN1918103, the reaction scheme is as follows, p-xylene is converted into 2-chloro-1- (2, 5-dimethylphenyl) ethanone (I) by using chloroacetyl chloride, the ketone is prepared into corresponding ketal of formula (III) by using diol of formula (II), then the ketal of formula (III) is rearranged to obtain a mixture of corresponding hydroxyalkyl 2, 5-dimethylphenylacetic acid of formula (IV) and bis (2, 5-dimethylphenylacetic acid) diester of formula (V), and finally the mixture is hydrolyzed to obtain 2, 5-dimethylphenylacetic acid. The method has long synthesis steps and complicated process.
3. Japanese patent JP2008291008 discloses a preparation method for preparing 2, 5-dimethylphenylacetic acid. The reaction process is as follows, 2, 5-dimethyl acetophenone is used as an initial raw material, and 2, 5-dimethyl phenylacetic acid is synthesized through coupling and hydrolysis reaction. The process produces a large amount of sulfur-containing waste and may also produce volatile sulfides with very foul odors, which are very environmentally unfriendly.
4. A preparation method for preparing 2, 5-dimethylphenylacetic acid is disclosed in United states science and technology Co., Ltd, CN 102140062A. The reaction process is as follows, p-xylene is used as an initial raw material, and 2, 5-dimethyl phenylacetic acid is synthesized through chloromethylation and palladium-catalyzed CO addition reaction. The method needs valuable catalysts such as tetraphenylphosphonium palladium and the like, has higher cost and has low feasibility of industrialization.
5. A preparation method for preparing 2, 5-dimethylphenylacetic acid is disclosed in southeast university patent CN 103804176A. The reaction process is as follows, p-xylene is used as an initial raw material, and 2, 5-dimethyl phenylacetic acid is synthesized through bromomethylation and CO addition reaction catalyzed by noble metal. The process also requires the use of bis-triphenylphosphine palladium dichloride, [ RhCl (COD)2]2And noble metal catalysts limit the industrial production.
In conclusion, the existing preparation methods of 2, 5-dimethylphenylacetic acid respectively have the problems of large toxicity of raw materials, more synthesis steps, more complex reaction types, high price of catalysts, low yield of synthesized products and the like.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: provides a synthesis method of 2, 5-dimethylphenyl acetic acid with mild reaction, short steps and no use of expensive/toxic raw materials.
The technical scheme for solving the technical problems is as follows:
a method for synthesizing 2, 5-dimethylphenyl acetic acid comprises the following steps:
(1)2, 5-dimethylbenzyl halide reacts with magnesium to generate Grignard reagent 2, 5-dimethylbenzyl magnesium halide;
(2)2, 5-dimethyl benzyl magnesium halide reacts with carbon dioxide to generate 2, 5-dimethyl phenylacetic acid;
the reaction formula of the above reaction is as follows:
Preferably, the molar ratio of the 2, 5-dimethylbenzyl halide to the magnesium in the step (1) is 1: 0.8 to 2.0; further, in the step (1), the molar ratio of the 2, 5-dimethylbenzyl halide to the magnesium is 1: 1.0 to 2.0; further, in the step (1), the molar ratio of the 2, 5-dimethylbenzyl halide to the magnesium is 1: 1.05 to 1.2.
Preferably, in the step (1), an initiator iodine, 1, 2-dibromoethane, an isopropyl grignard reagent and the like are further added, and the molar ratio of the initiator to the 2, 5-dimethylbenzyl halide is 1: 0.0001 to 0.05; further, the molar ratio of the initiator to the 2, 5-dimethylbenzyl halide is 1: 0.0005 to 0.01.
Preferably, the solvent used in step (1) includes ether solvents such as tetrahydrofuran, 2-methyltetrahydrofuran, and diethyl ether, or a mixed solvent of an ether solvent and toluene.
Preferably, in the step (1), the 2, 5-dimethylbenzyl halide is added to the rest of the reaction reagents in batches, the first addition is 10-20% of the total amount of the 2, 5-dimethylbenzyl halide, and the rest is added after the reaction solution turns to be off-white.
Preferably, the carbon dioxide used in the step (2) comprises carbon dioxide gas or dry ice.
Preferably, in the step (2), the molar ratio of the 2, 5-dimethylbenzyl magnesium halide to the carbon dioxide is 1: 0.9 to 20.0; further, in the step (2), the molar ratio of the 2, 5-dimethyl benzyl magnesium halide to the carbon dioxide is 1: 1.1 to 10.0; further, in the step (2), the molar ratio of the 2, 5-dimethylbenzyl magnesium halide to the carbon dioxide is 1: 5.0 to 10.0.
The Chinese naming of the compounds of the present invention conflicts with the structural formula, whichever is more.
The invention has the advantages that the use of expensive noble metal catalyst and/or virulent cyaniding reagent is avoided in the synthetic process of the 2, 5-dimethylphenylacetic acid, the used reagent is environment-friendly, the cost is reduced, the process is simplified, the reaction steps are shortened, the yield is higher, the defects of the prior art are overcome, and the method is suitable for large-scale industrial production.
Detailed Description
The invention is illustrated but not limited by the following examples. The technical solutions protected by the present invention are all the simple replacements or modifications made by the skilled person in the art.
Example 1:
in a 250mL dry four-neck flask, vacuum pumping and nitrogen replacement system three times, then under nitrogen protection, adding 60mL anhydrous tetrahydrofuran, 3.46g magnesium chips (molecular weight 24.3, 142.27mmol, 1.1eq) and a small particle of iodine (15mg) in sequence, heating to 60 ℃, slowly adding about one tenth of tetrahydrofuran solution of 2, 5-dimethyl benzyl chloride [20g 2, 5-dimethyl benzyl chloride (molecular weight 154.64, 129.33mmol, 1eq) dissolved in 30mL tetrahydrofuran ] dropwise, the temperature does not rise obviously, stirring for about 20 minutes at the temperature, at this time, the temperature is observed to rise obviously, and the reflux state is reached, and the yellow color in the solution fades and turns to grey. The remaining 2, 5-dimethylbenzyl chloride in tetrahydrofuran was slowly added dropwise over about 40 minutes. After the dropping, the temperature was maintained for 1 hour, and it was observed that the magnesium chips in the reaction solution had substantially disappeared. The reaction mixture was cooled to 20 ℃ and dried 56.91g of carbon dioxide gas (molecular weight 44, 1.29mol, 10eq) was slowly introduced, after which stirring was continued for 1 hour at about 20 ℃. Adding 50mL of saturated ammonium chloride solution for extraction and inactivation reaction, distilling under reduced pressure to remove tetrahydrofuran, extracting a water phase with 40mL of dichloromethane for three times, combining dichloromethane phases, evaporating dichloromethane by negative pressure to dryness to obtain 19.7g (with a molecular weight of 164.2, 21.24g theoretically) of white solid with the purity of 99.3 percent, namely the 2, 5-dimethylphenylacetic acid, and the mass yield of 92.10 percent.
(1H-NMR(CDCl3)δ:2.28(s,3H),2.31(s,3H),3.63(s,2H),7.01(m,2H),7.08(d,1H))。
Example 2:
in a 250mL dry four-neck flask, vacuum was applied and the system was replaced with nitrogen three times, then 60mL of anhydrous ether, 3.30g of magnesium turnings (molecular weight 24.3, 135.80mmol, 1.05eq) and a small amount of iodine (100mg) were added in sequence under nitrogen protection, the temperature was raised to 30 ℃, about one fifth of the ether solution of 2, 5-dimethylbenzyl bromide (25.75 g of 2, 5-dimethylbenzyl bromide (molecular weight 199.09, 129.33mmol, 1eq) was dissolved in 30mL of ether) was slowly added dropwise, the temperature did not rise significantly, and the mixture was stirred at this temperature for about 30 minutes, at which time the temperature was observed to rise significantly, reaching reflux, while the yellow color in the solution faded to off-white. The remaining 2, 5-dimethylbenzyl bromide in ether is slowly added dropwise, and the dropwise addition is finished in about 40 minutes. After the dropping, the temperature was maintained for 1 hour, and it was observed that the magnesium chips in the reaction solution had substantially disappeared. The reaction mixture was cooled to 20 ℃ and dried 56.91g of carbon dioxide gas (molecular weight 44, 1.29mol, 10eq) was slowly introduced, after which stirring was continued for 1 hour at about 20 ℃. Adding 50mL of saturated ammonium chloride solution for extraction and sterilization reaction, extracting with 60mL of ethyl acetate for three times, combining ethyl acetate phases, and distilling under reduced pressure to remove ethyl acetate to obtain 19.8g (the molecular weight is 164.2, 21.24g is obtained theoretically) of white solid with the purity of 99.1 percent, namely the 2, 5-dimethylphenylacetic acid, and the mass yield is 92.38 percent.
(1H-NMR(CDCl3)δ:2.28(s,3H),2.31(s,3H),3.63(s,2H),7.01(m,2H),7.08(d,1H))。
Example 3:
in a 250mL dry four-neck flask, vacuum was applied and the system was replaced with nitrogen three times, then 60mL of anhydrous ether, 3.77g of magnesium turnings (molecular weight 24.3, 155.20mmol, 1.2eq) and a small amount of iodine (50mg) were added in sequence under nitrogen protection, the temperature was raised to 60 ℃, about one fifth of the ether solution of 2, 5-dimethylbenzyl bromide (25.75 g of 2, 5-dimethylbenzyl bromide (molecular weight 199.09, 129.33mmol, 1eq) was dissolved in 30mL of ether) was slowly added dropwise, the temperature did not rise significantly, and stirring was carried out at this temperature for about 30 minutes, at which time the temperature was observed to rise significantly, reaching reflux, while the yellow color in the solution faded to off-white. The remaining 2, 5-dimethylbenzyl bromide in ether was slowly added dropwise over about 40 minutes. After the dropping, the temperature was maintained for 1 hour, and it was observed that the magnesium chips in the reaction solution had substantially disappeared. The reaction mixture was cooled to 20 ℃ and dried 28.45g of carbon dioxide (molecular weight 44, 0.65mol, 5eq) was slowly introduced, after which stirring was continued for 1 hour at about 20 ℃. Adding 50mL of saturated ammonium chloride solution for extraction and sterilization reaction, extracting with 60mL of ethyl acetate for three times, combining ethyl acetate phases, and distilling under reduced pressure to remove ethyl acetate to obtain 19.6g (the molecular weight is 164.2, 21.24g is obtained theoretically) of white solid with the purity of 99.3 percent, namely 2, 5-dimethylphenylacetic acid, and the mass yield is 91.63 percent.
(1H-NMR(CDCl3)δ:2.28(s,3H),2.31(s,3H),3.63(s,2H),7.01(m,2H),7.08(d,1H))。
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications are all within the scope of the present invention.
Claims (9)
1. A synthetic method of 2, 5-dimethylphenyl acetic acid is characterized by comprising the following steps:
(1)2, 5-dimethylbenzyl halide reacts with magnesium to generate Grignard reagent 2, 5-dimethylbenzyl magnesium halide;
(2)2, 5-dimethyl benzyl magnesium halide reacts with carbon dioxide to generate 2, 5-dimethyl phenylacetic acid;
the reaction formula of the above reaction is as follows:
wherein X is chlorine or bromine; and (2) adding the 2, 5-dimethylbenzyl halide into the rest of reaction reagents in batches in the step (1), wherein the adding amount of the first batch is 10-20% of the total amount of the 2, 5-dimethylbenzyl halide, and the rest is added after the reaction solution turns to be grey white.
2. The method for synthesizing 2, 5-dimethylphenylacetic acid according to claim 1, wherein the molar ratio of the 2, 5-dimethylbenzyl halide to the magnesium in the step (1) is 1: 0.8 to 2.0.
3. The method for synthesizing 2, 5-dimethylphenylacetic acid according to claim 2, wherein the molar ratio of the 2, 5-dimethylbenzyl halide to the magnesium in the step (1) is 1: 1.0 to 2.0.
4. The method for synthesizing 2, 5-dimethylphenyl acetic acid according to claim 1, wherein an initiator iodine, 1, 2-dibromoethane or an isopropyl grignard reagent is further added in the step (1), and the molar ratio of the initiator to the 2, 5-dimethylbenzyl halide is 1: 0.0001 to 0.05.
5. The method for synthesizing 2, 5-dimethylphenylacetic acid according to claim 1, wherein the solvent used in the step (1) is an ether solvent of tetrahydrofuran, 2-methyltetrahydrofuran or diethyl ether or a mixed solvent of the ether solvent and toluene.
6. The method for synthesizing 2, 5-dimethylphenylacetic acid according to claim 1, wherein the carbon dioxide used in the step (2) comprises carbon dioxide gas or dry ice.
7. The method for synthesizing 2, 5-dimethylphenyl acetic acid according to claim 1, wherein the molar ratio of the 2, 5-dimethylphenylmagnesium halide to the carbon dioxide in the step (2) is 1: 0.9 to 20.0.
8. The method for synthesizing 2, 5-dimethylphenyl acetic acid according to claim 7, wherein the molar ratio of the 2, 5-dimethylphenylmagnesium halide to the carbon dioxide in the step (2) is 1: 1.1 to 10.0.
9. The method for synthesizing 2, 5-dimethylphenyl acetic acid according to claim 8, wherein the molar ratio of the 2, 5-dimethylphenylmagnesium halide to the carbon dioxide in the step (2) is 1: 5.0 to 10.0.
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| CN112239402A (en) * | 2020-10-28 | 2021-01-19 | 爱斯特（成都）生物制药股份有限公司 | Preparation method of 2, 5-dimethoxy phenylacetic acid |
| CN112321413A (en) * | 2020-10-28 | 2021-02-05 | 爱斯特（成都）生物制药股份有限公司 | Preparation method of 2, 5-dimethoxy phenylacetic acid |
| CN115073383B (en) * | 2021-03-16 | 2023-07-18 | 四川大学 | Synthesis method of aryl acetic acid compound |
| CN114409524A (en) * | 2021-12-31 | 2022-04-29 | 上海柏狮生物科技有限公司 | Preparation method of 2, 6-dichlorophenylacetic acid |
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| CN1918103A (en) * | 2004-02-04 | 2007-02-21 | 拜尔农作物科学股份公司 | Method for producing 2,5-dimethylphenyl acetic acid |
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| CN104530002A (en) * | 2015-01-29 | 2015-04-22 | 天津梅花生物医药科技有限公司 | Bilastine compound and preparation method thereof |
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| CN1918103A (en) * | 2004-02-04 | 2007-02-21 | 拜尔农作物科学股份公司 | Method for producing 2,5-dimethylphenyl acetic acid |
| JP2008291008A (en) * | 2007-04-24 | 2008-12-04 | Daicel Chem Ind Ltd | Production method of 2,5-dimethylacetophenone derivative, and production method of 2,5-dimethylphenyl acetic acid obtained from 2,5-dimethylacetophenone derivative, and derivative thereof |
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