Synthesis method of pesticide intermediate 2, 6-dimethyl-1-indanone

Abstract

The invention belongs to the field of pesticides, and particularly relates to a synthesis method of a pesticide intermediate 2, 6-dimethyl-1-indanone. The preparation method comprises the following steps: 1) in a polar solvent, performing base catalysis on diethyl methylmalonate and p-methyl benzyl halide to obtain diester; (2) catalyzing the diester by strong inorganic acid at a relatively low temperature, and carrying out decarboxylation reaction to obtain phenylpropionic acid; 3) carrying out acyl halogenation on phenylpropionic acid to obtain phenylpropionyl halide; and 4) carrying out Friedel-Crafts reaction on the benzene propionyl halide under the action of a catalyst, and synthesizing to obtain the 2, 6-dimethyl-1-indanone. In the diester synthesis process, the raw materials diethyl methylmalonate and p-methyl benzyl halide react in the polar solvent under the catalysis of alkali, the reaction condition is mild, the reaction temperature can be reduced from 150 DEG C to 40-50 DEG C, the energy consumption in the reaction process is greatly reduced, the intrinsic safety of the process is improved, and the method is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of pesticides, and particularly relates to a method for synthesizing a pesticide intermediate 2,6-dimethyl-1-indanone. Background Art

[0002] 2,6-dimethyl-1-indanone is used as an intermediate for the synthesis of fine chemicals and active ingredients of agricultural chemicals. The synthesis method reported in the literature is as follows: p-methylbenzyl chloride is used as a raw material, and diethyl methylmalonate is reacted at a high temperature of 150°C under the catalysis of potassium carbonate to obtain an intermediate 1 diester, and the diester is refluxed in a hydrochloric acid / acetic acid system to obtain an intermediate 2-phenylpropionic acid. Intermediate 2 is cyclized in a polyphosphoric acid reaction system to obtain 2,6-dimethyl-1-indanone. In this synthesis method, the synthesis temperature of intermediate 1 is high, and intermediate 2 uses a mixed acid system of hydrochloric acid / acetic acid, which results in a large amount of waste acid and is difficult to recycle, making it unsuitable for industrial production; in the synthesis of intermediate 3, a large amount of polyphosphoric acid is used, and there are many impurities in the reaction process, and it is difficult to recycle the polyphosphoric acid after post-treatment, so it is difficult to achieve industrialization.

[0003] CN108329197A discloses that p-methylbenzyl chloride and methyl propionate are used as starting materials, reacted under the action of sodium methoxide to obtain intermediate 2-phenylpropionic acid methyl ester, and then subjected to saponification and acidification to obtain intermediate 2-phenylpropionic acid, and intermediate 2 is subjected to acyl chloride and aluminum chloride catalyzed cyclization in two steps to obtain 2,6-dimethyl-1-indanone. In the scheme described in the document, p-methylbenzyl chloride and sodium methoxide are prone to substitution reaction, resulting in little reaction with methyl propionate, low yield, and not suitable for industrial production.

[0004] In summary, the existing synthesis method of 2,6-dimethyl-1-indanone has problems such as high temperature reaction conditions, large amount of waste acid generation, difficulty in recycling polyphosphoric acid and low yield. It is urgent to develop a more efficient, environmentally friendly and suitable for industrial production synthesis method. Summary of the invention

[0005] In view of the problems existing in the synthesis process adopted by the current prior art, the purpose of the present invention is to provide a method for synthesizing the pesticide intermediate 2,6-dimethyl-1-indanone. The method of the present invention uses diethyl methylmalonate and p-methylbenzyl halide as starting materials, and obtains the product 2,6-dimethyl-1-indanone through condensation, decarboxylation, chlorination and catalytic ring closure reaction.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for synthesizing a pesticide intermediate 2,6-dimethyl-1-indanone, which uses diethyl methylmalonate and p-methylbenzyl halide as raw materials, and sequentially undergoes condensation, decarboxylation, acyl halide, and catalytic ring closure to obtain the product 2,6-dimethyl-1-indanone;

[0008] Specifically:

[0009] 1) In a polar solvent, diethyl methylmalonate and p-methylbenzyl halide are reacted with base to obtain a diester (intermediate 1);

[0010] 2) The diester is decarboxylated under a relatively low temperature condition with a strong inorganic acid as catalyst to obtain phenylpropionic acid (intermediate 2);

[0011] 3) Phenylpropionic acid is halogenated to obtain phenylpropionic acid halide (intermediate 3);

[0012] 4) Phenyl propionyl halide undergoes Friedel-Crafts reaction under the action of a catalyst to synthesize 2,6-dimethyl-1-indanone. The reaction formula is as follows:

[0013]

[0014] p-methylbenzyl halide is p-methylbenzyl chloride or p-methylbenzyl bromide;

[0015] The phenylpropionyl halide is phenylpropionyl chloride or phenylpropionyl bromide;

[0016] The strong inorganic acid is sulfuric acid, hydrochloric acid, phosphoric acid, and the preferred strong inorganic acid is sulfuric acid;

[0017] Furthermore, phenylpropanoyl halide undergoes Friedel-Crafts reaction under the action of a catalyst, and then undergoes hydrolysis to synthesize 2,6-dimethyl-1-indanone; the hydrolysis reagent is 5-10% hydrochloric acid solution; the molar ratio of the hydrolysis reagent to the catalyst is 1-2:1; the hydrolysis time is 2-4h; and the hydrolysis temperature is 5-40°C.

[0018] The polar solvent in the synthesis of intermediate 1 (diester) is one or more of methanol, ethanol, propylene glycol, tetrahydrofuran and dimethyltetrahydrofuran.

[0019] The base in the synthesis of intermediate 1 (diester) is an organic base or an inorganic base; the organic base is solid (liquid) sodium methoxide, solid (liquid) sodium ethoxide, sodium tert-butoxide, DBU; the organic base is solid sodium hydroxide, solid potassium hydroxide.

[0020] In the synthesis of intermediate 1 (diester), the reaction temperature is 40-80°C and the reaction time is 4-6h.

[0021] Preferably, under organic base catalysis, the reaction temperature is preferably 40-50°C, and under inorganic base catalysis, the reaction temperature is preferably 50-80°C.

[0022] In the synthesis of intermediate 1 (diester), the molar ratio of p-methylbenzyl halide to diethyl methylmalonate is 1-2:1, and the molar ratio of alkali to diethyl methylmalonate is 1.5-2:1.

[0023] The decarboxylation reaction in the synthesis of intermediate 2 (phenylpropionic acid) is carried out in a microchannel reactor under the catalysis of a strong inorganic acid with a concentration of 50-80%.

[0024] The microchannel reactor includes four reaction modules, the first reaction module is a material mixing preheating module, the second, third and fourth modules are reaction modules, the preheating module temperature is 30-50°C, and the reaction module temperature is 70-100°C. In the synthesis of intermediate 2 (phenylpropionic acid), two reaction materials, diester and strong inorganic acid aqueous solution, enter the microchannel reaction module at the same time, and the feed flow rate ratio of diester to strong inorganic acid is 1:2.5-1:5.

[0025] The acyl halide solvent in the synthesis of intermediate 3 (phenylpropanoyl halide) includes but is not limited to dichloromethane, dichloroethane, toluene, cyclohexane, xylene, benzene, and acetonitrile.

[0026] The acyl halide reagent includes but is not limited to triphosgene, thionyl chloride, phosphorus trichloride, phosphorus tribromide, NBS, and NCS, and triphosgene, thionyl chloride, and NBS are particularly preferred.

[0027] The molar ratio of the acyl halide reagent to phenylpropionic acid is 1.2-1.8:1.

[0028] Synthesis of intermediate 3 (phenylpropionyl halide), reaction temperature 55-90°C, reaction time 1-5h

[0029] The intermediate 3 (phenylpropionyl halide) in the synthesis of 2,6-dimethyl-1-indanone is reacted to form a ring under the catalysis of a strong Lewis acid or a protonic acid. The catalyst used is aluminum trichloride, ferric trichloride, zinc chloride, and boron trifluoride. Aluminum trichloride and ferric trichloride are particularly preferred. The molar ratio of the catalyst to the phenylpropionyl halide is 1-2:1.

[0030] Under solvent conditions, the intermediate 3 (phenylpropanoyl halide) in the synthesis of 2,6-dimethyl-1-indanone is reacted into a ring under the catalysis of a strong Lewis acid or a protonic acid, and the solvent is a dichloroethane solution.

[0031] The reaction temperature of the Friedel-Crafts reaction for synthesizing 2,6-dimethyl-1-indanone is 5-30°C and the reaction time is 2-8h.

[0032] Compared with the prior art, the advantages of the present invention are:

[0033] In the diester synthesis process of the present invention, the raw materials diethyl methylmalonate and p-methylbenzyl halide are reacted in a polar solvent under the catalysis of a base to obtain the diester. The reaction conditions are mild, and the reaction temperature can be reduced from 150° C. to 40-50° C., which greatly reduces the energy consumption of the reaction process, improves the intrinsic safety of the process, and is suitable for industrial production.

[0034] The decarboxylation process adopted in the synthesis process of phenylpropionic acid of the present invention is that the diester (intermediate 1) can be decarboxylated in a sulfuric acid system at a relatively low temperature (70-100 DEG C) through a microchannel reactor, and the conversion rate is above 98%. Compared with the traditional kettle reactor, the process has the advantages of short reaction time, low synthesis temperature, small equipment occupation volume, small equipment corrosion, high reaction safety factor, etc., and has broad prospects in industrial application.

[0035] The phenylpropionic acid (intermediate 2) of the present invention is subjected to acyl chlorination to obtain phenylpropionic acid chloride (intermediate 3); the intermediate 3 undergoes Friedel-Crafts reaction to form a ring under the action of a catalyst, replacing the catalysis of polyphosphoric acid. The new process has a high synthesis yield, a mature three-waste treatment process, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the mass spectrum of 2,6-dimethyl-1-indanone prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0037] Example 1

[0038] 1.1 Preparation of Intermediate 1 (Diester)

[0039] (8.7g, 0.05mmol) diethyl methylmalonate, (4.05g, 0.075mmol) sodium methoxide, (32g, 1mol) methanol were added to a 250mL flask, and (7.7g, 0.055mol) p-methylbenzyl chloride was added dropwise at a temperature of 45±2°C. The addition was completed in about 2h, and the reaction was kept warm for 4h. After the reaction was completed, the mixture was cooled to room temperature, 30g toluene and 45g water were added for extraction, and after the oil layer was extracted, the solvent was removed to obtain 13.8g of intermediate 1 (diester), with a yield of 99%.

[0040] 1.2 Preparation of intermediate 2 (phenylpropionic acid)

[0041] The microchannel reactor (FlowPlate Lab Microreactor by EHRFELD 0224-2-C-2004-F) was pre-fed with 80% sulfuric acid at a feed rate of 55.2 g / h, and the preheating plate temperature was controlled at 40°C. The feed pump of intermediate 1 was turned on, and the feed flow rate was controlled at 13.8 g / h; the temperature of the second reaction module was controlled at 70°C, the temperature of the third reaction module was 80°C, and the temperature of the fourth reaction module was 85°C by an external high and low temperature circulation machine; the materials were collected in a glass reaction bottle with stirring. The temperature of the reacted material was maintained at 40°C, 50 g of toluene was added for extraction, 50 g of water was added to the extracted oil layer for washing, and 8.6 g of intermediate 2 (phenylpropionic acid) was obtained by separation and desolventization, with a yield of 98%.

[0042] 1.3 Preparation of intermediate 3 (phenylpropionyl chloride)

[0043] Add 43g of dichloroethane to the obtained intermediate 2 (8.6g, 0.048mmol), stir and raise the temperature to 70°C, then add dropwise (6.9g, 0.058mmol) of acyl chloride reagent dichlorothionyl, and add dropwise for 4h. After the addition is completed, keep the temperature for 2h to obtain 52.4g of dichloroethane solution of intermediate 3, with a content of intermediate 3 of 17.9% and a yield of 99%.

[0044] 1.4 Preparation of 2,6-dimethyl-1-indanone

[0045] Add (6.8g, 0.051mmol) aluminum chloride to 50g dichloroethane, stir, then cool to 10℃, add 52.4g dichloroethane solution of intermediate 3 (phenylpropionyl chloride) dropwise at 10℃, then keep warm at 10℃ for 3h, after the end of the insulation, add 50g 5% hydrochloric acid aqueous solution dropwise at 25℃ within 3h, then keep warm and stir for 2h, extract with dichloroethane, desolventize, and distill to obtain 7.55g of refined 2,6-dimethyl-1-indanone with a content of 95.5%. The mass spectrum of 2,6-dimethyl-1-indanone is shown in Figure 1 The comprehensive yield of this process route is 90.2%.

[0046] Example 2

[0047] 2.1 Preparation of Intermediate 1 (Diester)

[0048] (8.7g, 0.05mmol) diethyl methylmalonate, (6.8g, 0.1mmol) sodium ethoxide, (46g, 1mol) ethanol were added to a 250mL flask, and (7.7g, 0.055mol) p-methylbenzyl chloride was added dropwise at a temperature of 45±2°C for about 2h. After the addition was completed, the mixture was kept warm for 4h. After the reaction was completed, the mixture was cooled to room temperature, 30g toluene and 45g water were added for extraction, and after the oil layer was extracted, the solvent was removed to obtain 13.7g of intermediate 1 (diester), with a yield of 98%.

[0049] 2.2 Preparation of intermediate 2 (phenylpropionic acid)

[0050] The microchannel reactor (FlowPlate Lab Microreactor by EHRFELD 0224-2-C-2004-F) was pre-fed with 70% sulfuric acid at a feed rate of 55.2 g / h, and the preheating plate temperature was controlled at 40°C. The feed pump of intermediate 1 was turned on, and the feed flow rate was controlled at 13.7 g / h; the temperature of the second reaction module was controlled at 80°C, the temperature of the third reaction module was 85°C, and the temperature of the fourth reaction module was 90°C by an external high and low temperature circulation machine; the materials were collected in a glass reaction bottle with stirring. The temperature of the reacted material was maintained at 40°C, 50g of toluene was added for extraction, 50g of water was added to the extracted oil layer for washing, and 8.56g of intermediate 2 (phenylpropionic acid) was obtained by separation and desolventization, with a yield of 97.6%.

[0051] 2.3 Preparation of intermediate 3 (phenylpropionyl chloride)

[0052] Add 20 g of dichloroethane to the obtained 8.56 g of intermediate 2 (phenylpropionic acid), stir and raise the temperature to 90°C, at this temperature, add dropwise (4.6 g, 0.016 mmol) of triphosgene, an acyl chloride reagent, and 20 g of a mixed solution of dichloroethane, and add dropwise for 4 hours. After the addition is completed, keep the temperature for 2 hours to obtain 31.8 g of a dichloroethane solution of intermediate 3, with a content of intermediate 3 of 31.8% and a yield of 98.5%.

[0053] 2.4 Preparation of 2,6-dimethyl-1-indanone

[0054] Add (7.6g, 0.047) ferric chloride to 20g dichloroethane, stir and dissolve, then cool to 10°C, add 31.8g dichloroethane solution of intermediate 3 (phenylpropionyl chloride) dropwise at 10°C, and then keep warm at 10°C for 1h. After the insulation, add 50g 5% hydrochloric acid aqueous solution dropwise within 3h at 25°C, and then keep warm and stir for 2h. Then extract, desolventize and distill to obtain 7.52g of refined 2,6-dimethyl-1-indanone with a content of 95.4%. The comprehensive yield of 2,6-dimethyl-1-indanone to raw material diethyl methylmalonate is 89.8% in this route.

[0055] Example 3

[0056] 3.1 Preparation of Intermediate 1 (Diester)

[0057] (8.7g, 0.05mmol) diethyl methylmalonate, (7.2g, 0.075mmol) sodium tert-butoxide, (74g, 1mol) tert-butanol were added to a 250mL flask, and (10.2g, 0.055mol) p-methylbenzyl bromide was added dropwise at 50±2°C for about 2h. The reaction was kept warm for 4h. After the reaction was completed, the mixture was cooled to room temperature, 30g toluene and 45g water were added for extraction, and after the oil layer was extracted, the solvent was removed to obtain 13.8g of intermediate 1, with a yield of 99%.

[0058] 3.2 Preparation of intermediate 2 (phenylpropionic acid)

[0059] The microchannel reactor (FlowPlate Lab Microreactor by EHRFELD 0224-2-C-2004-F) was pre-fed with 70% sulfuric acid at a feed rate of 45 g / h, and the preheating plate temperature was controlled at 50°C. The feed pump of intermediate 1 was turned on, and the feed flow rate was controlled at 13.8 g / h; the temperature of the second reaction module was controlled at 75°C, the temperature of the third reaction module was 85°C, and the temperature of the fourth reaction module was 90°C by an external high and low temperature circulation machine; the materials were collected in a glass reaction bottle with stirring. The temperature of the reacted material was maintained at 40°C, 50 g of toluene was added for extraction, 50 g of water was added to the extracted oil layer for washing, and 8.56 g of intermediate 2 (phenylpropionic acid) was obtained by separation and desolventization, with a yield of 97.6%.

[0060] 3.3 Preparation of intermediate 3 (phenylpropionyl bromide)

[0061] Add 20 g of dichloroethane to 8.56 g of the obtained intermediate 2, stir and raise the temperature to 90°C, at this temperature, add dropwise (7.3 g, 0.054 mmol) of phosphorus trichloride solution, an acyl chloride reagent, dropwise for 5 hours, and keep warm for 2 hours after the addition to obtain 29.3 g of dichloroethane solution of intermediate 3, with a content of intermediate 3 of 31.71% and a yield of 98.3%.

[0062] 3.4 Preparation of 2,6-dimethyl-1-indanone

[0063] Add ferric chloride (6.2 g, 0.045%) to 20 g of dichloroethane, stir and dissolve, then cool to 20°C, add 29.3 g of dichloroethane solution of intermediate 3 (phenylpropionyl bromide) dropwise at 20°C, and then keep warm at 20°C for 1 hour. After the insulation, add 50 g of 5% hydrochloric acid aqueous solution dropwise at 25°C within 3 hours, then keep warm and stir for 2 hours, extract, desolventize and distill to obtain 7.54 g of refined 2,6-dimethyl-1-indanone with a content of 95.3%, and the comprehensive yield of 2,6-dimethyl-1-indanone to raw material diethyl methylmalonate is 89.9% in this route.

[0064] Comparative Example 1

[0065] The difference from Example 1 is that the sulfuric acid concentration of the decarboxylation in step 2) is different, and the specific synthesis process is:

[0066] 4.1 Preparation of Intermediate 1 (Diester)

[0067] (8.7 g, 0.05 mmol) diethyl methylmalonate, (4.2 g, 0.075 mmol) potassium hydroxide, and (46 g, 1 mol) ethanol were added to a 250 mL flask, and (7.7 g, 0.055 mol) p-methylbenzyl chloride was added dropwise at 80±2°C for about 2 hours. The reaction was kept warm for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, 30 g toluene and 45 g water were added for extraction, and after the oil layer was extracted, the solvent was removed to obtain 13.8 g of intermediate 1, with a yield of 99%.

[0068] 4.2 Preparation of intermediate 2 (phenylpropionic acid)

[0069] The microchannel reactor was pre-fed with 40% sulfuric acid at a feed rate of 55.2 g / h, and the temperature of the preheating plate was controlled at 40°C. The feed pump of intermediate 1 was turned on, and the feed flow rate was controlled at 13.8 g / h; the temperature of the second reaction module was controlled at 70°C, the temperature of the third reaction module was 80°C, and the temperature of the fourth reaction module was 85°C by an external high and low temperature circulation machine; the materials were collected in a glass reaction bottle with stirring. After the reaction, the temperature of the material was maintained at 40°C, 50g of toluene was added for extraction, 50g of water was added to the extracted oil layer for washing, and 7.9g of intermediate 2 (phenylpropionic acid) was obtained by separation and desolventization, with a yield of 70%.

[0070] 4.3 Preparation of intermediate 3 (phenylpropionyl chloride)

[0071] Add 40 g of dichloroethane to the obtained intermediate 2 (7.9 g, 0.044 mmol), stir and raise the temperature to 70°C, then add dropwise (6.3 g, 0.053 mmol) of acyl chloride reagent dichlorothionyl, and add dropwise for 4 hours. After the addition is completed, keep the temperature for 2 hours to obtain 48.6 g of dichloroethane solution of intermediate 3, with a content of intermediate 3 of 17.75% and a yield of 99%.

[0072] 4.4 Preparation of 2,6-dimethyl-1-indanone

[0073] Aluminum trichloride (4.5 g, 0.034 mmol) was added to 50 g of dichloroethane and stirred. Then the temperature was lowered to 10°C, and 48.6 g of dichloroethane solution of intermediate 3 (phenylpropionyl chloride) was added dropwise at 10°C, and then kept warm for 1 hour at 10°C. After the insulation, 50 g of 5% acid water was added dropwise at 25°C within 3 hours, and then kept warm and stirred for 2 hours. After dichloroethane extraction, desolventization, and rectification, 5.39 g of refined 2,6-dimethyl-1-indanone with a content of 95.6% was obtained. The comprehensive yield of 2,6-dimethyl-1-indanone to raw material diethyl methylmalonate was 64.5%.

[0074] Comparative Example 2

[0075] The difference from Example 1 is that the temperature of decarboxylation in step 2) is different, and the specific synthesis process is:

[0076] 5.1 Preparation of Intermediate 1 (Diester)

[0077] (8.7 g, 0.05 mmol) diethyl methylmalonate, (4.2 g, 0.075 mmol) potassium hydroxide, and (46 g, 1 mol) ethanol were added to a 250 mL flask, and (7.7 g, 0.055 mol) p-methylbenzyl chloride was added dropwise at 80±2°C for about 2 hours. The reaction was kept warm for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, 30 g toluene and 45 g water were added for extraction, and after the oil layer was extracted, the solvent was removed to obtain 13.8 g of intermediate 1, with a yield of 99%.

[0078] 5.2 Preparation of Intermediate 2 (Phenylpropionic Acid)

[0079] The microchannel reactor was pre-fed with 80% sulfuric acid at a feed rate of 55.2 g / h, and the temperature of the preheating plate was controlled at 40°C. The feed pump of intermediate 1 was turned on, and the feed flow rate was controlled at 13.8 g / h; the temperature of the second reaction module was controlled at 65°C, the temperature of the third reaction module was 67°C, and the temperature of the fourth reaction module was 68°C by an external high and low temperature circulation machine; the materials were collected in a glass reaction bottle with stirring. After the reaction, the temperature of the material was maintained at 40°C, 50 g of toluene was added for extraction, 50 g of water was added to the extracted oil layer for washing, and 5.7 g of intermediate 2 (phenylpropionic acid) was obtained by separation and desolventization, with a yield of 65%.

[0080] 5.3 Preparation of intermediate 3 (phenylpropionyl chloride)

[0081] Add 40 g of dichloroethane to the obtained intermediate 2 (5.7 g, 0.032 mmol), stir and raise the temperature to 70°C, then add dropwise (5.0 g, 0.042 mmol) of acyl chloride reagent dichlorothionyl, and add dropwise for 4 hours. After the addition is completed, keep the temperature for 2 hours to obtain 46.2 g of dichloroethane solution of intermediate 3, with a content of intermediate 3 of 13.48% and a yield of 99%.

[0082] 5.4 Preparation of 2,6-dimethyl-1-indanone

[0083] Add (4.8g, 0.036mmol) aluminum chloride to 50g dichloroethane and stir. Then cool to 10℃, add 46.2g dichloroethane solution of intermediate 3 (phenylpropionyl chloride) dropwise at 10℃, then keep warm at 20℃ for 1h, add 50g 5% hydrochloric acid aqueous solution dropwise at 25℃, then keep warm and stir for 2h. After dichloroethane extraction, desolventization and rectification, 5.72g of refined 2,6-dimethyl-1-indanone was obtained, with a content of 95.0%. The yield of acyl chloride and cyclization was calculated to be 93%, and the comprehensive yield of 2,6-dimethyl-1-indanone to raw material diethyl methylmalonate was 68.1%.

[0084] As can be seen from the embodiment and comparative examples 1 and 2, the comparative example changes the sulfuric acid concentration and the reaction temperature of the microchannel reaction module in the decarboxylation conditions, resulting in a significant reduction in yield. Therefore, any change in the synthetic method of the present invention will significantly affect the synthetic effect, and therefore, the synthetic conditions and steps of the embodiment of the present invention can be coordinated to achieve the improvement of the process.

Claims

1. A method for synthesizing a pesticide intermediate 2,6-dimethyl-1-indanone, characterized in that: 1) In a polar solvent, diethyl methylmalonate and p-methylbenzyl halide are reacted by base catalysis to obtain a diester; 2) The diester is decarboxylated under a relatively low temperature condition with a strong inorganic acid as catalyst to obtain phenylpropionic acid; 3) Phenylpropionic acid is halogenated to obtain phenylpropionic acid halide; 4) Phenyl propionyl halide undergoes Friedel-Crafts reaction in the presence of a catalyst to synthesize 2,6-dimethyl-1-indanone.

2. The synthesis method according to claim 1, characterized in that Phenyl propionyl halide undergoes Friedel-Crafts reaction under the action of a catalyst, and then undergoes hydrolysis to synthesize 2,6-dimethyl-1-indanone; the hydrolysis reagent is a 5-10% hydrochloric acid solution; the molar ratio of the hydrolysis reagent to the catalyst is 1-2:1; the hydrolysis time is 2-4 hours; and the hydrolysis temperature is 5-40°C.

3. The synthesis method according to claim 1, characterized in that The base used in the synthesis of diesters is an organic base or an inorganic base.

4. The synthesis method according to claim 3, characterized in that The reaction temperature in the synthesis of diester is 40-80°C, the reaction time is 4-6h, the reaction temperature is 40-50°C under organic base catalysis, and the reaction temperature is 50-80°C under inorganic base catalysis.

5. The synthesis method according to claim 1, characterized in that In the synthesis of the diester, the molar ratio of p-methylbenzyl halide to diethyl methylmalonate is 1-2:1, and the molar ratio of alkali to diethyl methylmalonate is 1.5-2:

1.

6. The synthesis method according to claim 1, characterized in that The decarboxylation reaction in the synthesis of phenylpropionic acid is carried out in a microchannel reactor, the reaction temperature is 70-100°C, and the reaction time is 4-8 hours; the flow rate ratio of diester to strong inorganic acid in the synthesis of phenylpropionic acid is 1:2.5-1:5, and the concentration of strong inorganic acid is 50-80%.

7. The synthesis method according to claim 1, characterized in that The acyl halide reagent in the synthesis of phenylpropanoyl halide is one or more of triphosgene, thionyl chloride, phosphorus trichloride, phosphorus tribromide, NBS, and NCS; The molar ratio of the acyl halide reagent to phenylpropionic acid is 1.2-1.8:

1.

8. The synthesis method according to claim 1, characterized in that The acyl chlorination reaction temperature in the synthesis of phenylpropanoyl halide is 55-90°C and the reaction time is 1-5h.

9. The synthesis method according to claim 1, characterized in that The catalyst in the synthesis of 2,6-dimethyl-1-indanone is a strong Lewis acid or a protonic acid, and the molar ratio of the catalyst to the phenylpropanoyl halide is 1-2:

1.

10. The synthesis method according to claim 1, characterized in that The reaction temperature of the Friedel-Crafts reaction for synthesizing 2,6-dimethyl-1-indanone is 5-30°C and the reaction time is 2-8h.

Images