A kind of preparation method of acetosyringone

Abstract

The present application provides a preparation method of acetosyringone, and relates to the technical field of organic preparation. The method includes: ethyl acetate, 2,6-dimethoxyphenol, and acyl compounds are mixed, and the first reaction obtains the first intermediate; the organic solution of the first intermediate is mixed with the aqueous phase, extracted, liquid separation is performed to obtain an organic phase, the organic phase is dried to obtain a solid product, the solid product and ethanol are mixed, and recrystallization obtains a second intermediate; the second intermediate, a heteropolyacid supported catalyst, and a chlorinated organic solvent are mixed, and the second reaction obtains acetosyringone; the heteropolyacid supported catalyst includes a heteropolyacid carrier and a metal salt arranged on the surface of the heteropolyacid carrier or / and in the pore. The heteropolyacid carrier not only has a catalytic effect itself, but also the metal salt of its load can significantly improve the reaction activity, reduce the reaction temperature, and reuse after cleaning, which significantly reduces the cost of consumables.

Description

Technical Field

[0001] The present application relates to the technical field of organic matter preparation, and in particular to a method for preparing acetosyringone. Background Art

[0002] Acetosyringone plays a significant role in biology, agriculture, medicine and other fields. At present, although the synthesis of acetosyringone is simple and the raw materials are relatively cheap, the conversion efficiency is not high, and the large amount of waste phosphoric acid generated later is difficult to handle, making it difficult to apply to scale-up production. In addition, the acetyl chloride and AlCl3 used are also easily hydrolyzed in a humid environment to produce acid mist. Therefore, this process has high requirements for equipment safety and corrosion resistance in actual production, which is bound to increase related investment.

[0003] Based on this, it is urgent to provide a new method for preparing acetosyringone to solve the above problems. Summary of the invention

[0004] The purpose of the present application is to provide a method for preparing acetosyringone to solve the above problems.

[0005] To achieve the above objectives, the present application provides a method for preparing acetosyringone, comprising:

[0006] Mixing ethyl acetate, 2,6-dimethoxyphenol and an acyl compound, and performing a first reaction to obtain a first intermediate;

[0007] The organic solution of the first intermediate and the aqueous phase are mixed, extracted, separated to obtain an organic phase, the organic phase is dried to obtain a solid product, the solid product and ethanol are mixed, and recrystallized to obtain a second intermediate;

[0008] The second intermediate, the heteropolyacid supported catalyst, and the chlorine-containing organic solvent are mixed, and a second reaction is performed to obtain acetosyringone;

[0009] The heteropolyacid supported catalyst includes a heteropolyacid carrier and a metal salt disposed on the surface of the heteropolyacid carrier or / and in the pores.

[0010] Optionally, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0011] A. The heteropoly acid carrier includes one or more of phosphotungstic acid, phosphomolybdic acid, and silicotungstic acid;

[0012] B. The metal salt includes one or more of trifluoromethanesulfonate metal salt, non-rare earth transition metal element salt, and rare earth metal salt.

[0013] Optionally, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0014] A. The chemical formula of the metal trifluoromethanesulfonate is: M(OTf) X ;

[0015] Among them, M includes Bi 3+ , Cu 2+ ,La 3+ , Mn 2+ Sn 2+ and Tb 3+ One or more of;

[0016] B. The metal elements in the non-rare earth transition metal element salt include one or more of Fe, Co, Ni, and Zn.

[0017] Optionally, the mass ratio of the metal salt to the heteropolyacid carrier is 0.8-1.2:100.

[0018] Optionally, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0019] A. the acyl compound comprises one or more of acetic anhydride, acetamide, and butyl acetate;

[0020] B. The chlorine-containing organic solvent includes one or more of dichloromethane, chloroform (trichloromethane), 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane.

[0021] Optionally, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0022] A. The molar ratio of the ethyl acetate, the 2,6-dimethoxyphenol, and the acyl compound is 4-4.5:1:1.05-1.4;

[0023] B. The mass ratio of the second intermediate to the heteropolyacid supported catalyst is 26-33:2.5-3.5.

[0024] Optionally, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0025] A. The temperature of the first reaction is 55-60°C and the time is 10h-12h;

[0026] B. The temperature of the second reaction is 25-35°C and the time is 20h-24h.

[0027] Optionally, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0028] A. NaHCO3 solution is also added to the liquid separation;

[0029] B. after carrying out the second reaction, further carry out post-treatment, the post-treatment comprising:

[0030] The reactant obtained after the second reaction is subjected to solid-liquid separation to obtain a liquid phase, the liquid phase and an inorganic alkaline compound are mixed, and the aqueous phase is obtained by layering, the aqueous phase and an acidic compound are mixed to obtain an acid-adjusted aqueous phase, the acid-adjusted aqueous phase and ethyl acetate are mixed, and the acetosyringone is extracted.

[0031] Optionally, the pH value of the aqueous phase after acid adjustment is 4.6-5.

[0032] Optionally, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0033] A. The inorganic alkaline compound includes one or more of NaOH, KOH, and ammonia water;

[0034] B. The acidic compound includes an organic acid and / or an inorganic acid.

[0035] Compared with the prior art, the beneficial effects of this application include:

[0036] The preparation method of acetosyringone provided in the present application comprises the following steps: first, esterifying 2,6-dimethoxyphenol with an acyl compound to obtain a first intermediate, and then recrystallizing the intermediate; and then, converting the phenol ester into the phenol ketone through a classic Fries rearrangement reaction using a green and non-toxic heteropolyacid-supported catalyst, wherein the heteropolyacid carrier not only has a catalytic effect itself, but the metal salt supported thereon can also significantly enhance the reaction activity and reduce the reaction temperature, and can also be reused after cleaning, thereby significantly reducing the cost of consumables. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0038] Figure 1 This is the NMR image of acetosyringone provided in Example 1. DETAILED DESCRIPTION

[0039] As used herein:

[0040] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0041] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0042] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0043] In these examples, parts and percentages are by mass unless otherwise indicated.

[0044] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.

[0045] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0046] The present application provides a method for preparing acetosyringone, comprising:

[0047] Mixing ethyl acetate, 2,6-dimethoxyphenol and an acyl compound, and performing a first reaction to obtain a first intermediate;

[0048] The organic solution of the first intermediate and the aqueous phase are mixed, extracted, separated to obtain an organic phase, the organic phase is dried to obtain a solid product, the solid product and ethanol are mixed, and recrystallized to obtain a second intermediate;

[0049] The second intermediate, the heteropolyacid supported catalyst, and the chlorine-containing organic solvent are mixed, and a second reaction is performed to obtain acetosyringone;

[0050] The heteropolyacid supported catalyst includes a heteropolyacid carrier and a metal salt disposed on the surface of the heteropolyacid carrier or / and in the pores.

[0051] In some embodiments, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0052] A. The heteropoly acid carrier includes one or more of phosphotungstic acid, phosphomolybdic acid, and silicotungstic acid;

[0053] B. The metal salt includes one or more of trifluoromethanesulfonate metal salt, non-rare earth transition metal element salt, and rare earth metal salt.

[0054] In some embodiments, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0055] A. The chemical formula of the metal trifluoromethanesulfonate is: M(OTf) X ;

[0056] Among them, M includes Bi 3+ , Cu 2+ ,La 3+ , Mn 2+ Sn 2+ and Tb 3+ One or more of;

[0057] B. The metal elements in the non-rare earth transition metal element salt include one or more of Fe, Co, Ni, and Zn.

[0058] In some embodiments, the mass ratio of the metal salt to the heteropolyacid carrier is 0.8-1.2:100.

[0059] Optionally, the mass ratio of the metal salt to the heteropolyacid carrier can be 0.8:100, 0.9:100, 1.0:100, 1.1:100, 1.2:100 or any value between 0.8-1.2:100.

[0060] In some embodiments, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0061] A. the acyl compound comprises one or more of acetic anhydride, acetamide, and butyl acetate;

[0062] Preferably, the acyl compound includes acetic anhydride, and acetic anhydride is selected to replace conventional acetyl chloride to esterify the phenolic compound, which reduces the production cost and avoids the environmental pollution problem caused by the fuming of acetyl chloride. At the same time, after the reaction, only alkali solution is needed to wash away the remaining acetic anhydride and the by-product acetic acid after hydrolysis, which greatly simplifies the post-treatment step of the first step of the esterification reaction;

[0063] B. The chlorine-containing organic solvent includes one or more of dichloromethane, chloroform (trichloromethane), 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane.

[0064] In some embodiments, the chlorine-containing organic solvent includes dichloromethane, which has a low boiling point and is easy to separate the product subsequently.

[0065] In some embodiments, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0066] A. The molar ratio of the ethyl acetate, the 2,6-dimethoxyphenol, and the acyl compound is 4-4.5:1:1.05-1.4;

[0067] Optionally, the molar ratio of ethyl acetate, 2,6-dimethoxyphenol, and acyl compound can be 4:1:1.05, 4.1:1:1.05, 4.2:1:1.05, 4.3:1:1.05, 4.4:1:1.05, 4.5:1:1.05, 4:1:1.1, 4:1:1.2, 4:1:1.3, 4:1:1.4, 4.5:1:1.4, or any value between 4-4.5:1:1.05-1.4;

[0068] B. The mass ratio of the second intermediate to the heteropolyacid supported catalyst is 26-33:2.5-3.5.

[0069] Optionally, the mass ratio of the second intermediate to the heteropolyacid supported catalyst can be 26:2.5, 28:2.5, 30:2.5, 32:2.5, 33:2.5, 26:3, 26:3.5 or any value between 26-33:2.5-3.5.

[0070] It should be noted that conventional methods usually use Lewis acid as a catalyst, and the dosage is generally 1.5-3 times that of the reactant phenol ester, and it cannot be reused; while the catalyst of the present application is a strongly acidic heteropolyacid as a carrier, and is loaded with a strongly acidic organic acid salt. Both substances have catalytic effects themselves and are reusable, so only a small amount of addition is required to achieve efficient catalysis.

[0071] In some embodiments, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0072] A. The temperature of the first reaction is 55°C-60°C and the time is 10h-12h;

[0073] Optionally, the temperature of the first reaction can be 55°C, 56°C, 57°C, 58°C, 59°C, 60°C or any value between 55°C and 60°C, and the time can be 10h, 11h, 12h or any value between 10h and 12h;

[0074] B. The temperature of the second reaction is 25°C-35°C and the time is 20h-24h.

[0075] Optionally, the temperature of the second reaction can be 25°C, 30°C, 35°C or any value between 25°C and 35°C, and the time can be 20h, 21h, 22h, 23h, 24h or any value between 20h and 24h.

[0076] In some embodiments, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0077] A. NaHCO3 solution is also added to the liquid separation;

[0078] It should be noted that the addition of alkaline solutions such as NaHCO3 solution can remove unreacted acyl compounds and generated acetic acid. When no more bubbles are generated, it indicates that the acid has been completely removed.

[0079] B. after carrying out the second reaction, further carry out post-treatment, the post-treatment comprising:

[0080] The reactant obtained after the second reaction is subjected to solid-liquid separation to obtain a liquid phase, the liquid phase and an inorganic alkaline compound are mixed, and the aqueous phase is obtained by layering, the aqueous phase and an acidic compound are mixed to obtain an acid-adjusted aqueous phase, the acid-adjusted aqueous phase and ethyl acetate are mixed, and the acetosyringone is extracted.

[0081] It should be noted that in the post-treatment process, the reactant obtained after the second reaction needs to be firstly added with alkali to be converted into sodium phenolate so as to be precipitated from the organic phase, and then the obtained precipitate is dissolved in water, and then the phenolic substance is recovered by the method of acidification-extraction-evaporation of the organic solvent. In this way, the purity of the product is improved, and in this way, not only the unreacted second intermediate and the obtained acetosyringone are separated, but also the by-products that do not react with the alkali (mainly diphenols and triphenols converted from methoxy groups to hydroxyls, which have a solubility greater than that of monophenols) can be removed by being trapped in the organic phase.

[0082] In some embodiments, the pH value of the aqueous phase after acid adjustment is 4.6-5.

[0083] Optionally, the pH value of the aqueous phase after acid adjustment can be any value between 4.6 and 5.

[0084] It should be noted that when the pH value of the aqueous phase after acid adjustment is 4.6-5, the conversion efficiency and extraction efficiency of phenol are the highest.

[0085] In some embodiments, the method for preparing acetosyringone satisfies at least one of the following conditions:

[0086] A. The inorganic alkaline compound includes one or more of NaOH, KOH, and ammonia water;

[0087] B. The acidic compound includes an organic acid and / or an inorganic acid.

[0088] In some optional embodiments, the organic acid includes HCOOH and / or CH3COOH.

[0089] In some optional embodiments, the inorganic acid includes H2SO4 and / or H3PO4.

[0090] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0091] Example 1

[0092] This embodiment provides a method for preparing acetosyringone, comprising:

[0093] S1: Add 400 mL of ethyl acetate to a 1 L three-necked flask, then add 154 g (1 mol) of 2,6-dimethoxyphenol and dissolve it completely, then slowly drop 122 mL (1.3 mol) of acetic anhydride into the three-necked flask, and react at 60 °C for 10 h;

[0094] S2: After the reaction is completed, the mixed solution obtained in S1 is mixed with an excess of saturated NaHCO3 solution. When no more bubbles are generated, the mixed solution is separated, the organic phase is taken, and the ethyl acetate is evaporated to obtain a crude product, 40 mL of hot ethanol is added to dissolve it all, and recrystallized at a temperature of -10°C to obtain 104.5 g of the intermediate product 2,6-dimethoxyphenylacetate (CAS: 944-99-0);

[0095] S3: Preparation of heteropolyacid supported catalyst: 1 g of trifluoromethanesulfonate Bi(OTf)3 was dissolved in 50 g of pure water, and then 100 g of sieved phosphotungstic acid (HPWO) was slowly added to the above solution, and stirred for 1.5 h while adding, so that the trifluoromethanesulfonate solution evenly penetrated into the pores of the phosphotungstic acid. After completion, the emulsion was completely evaporated and the remaining solid was ground to obtain a heteropolyacid supported catalyst;

[0096] S4: Add 500 mL of dichloromethane to a 1 L three-necked flask, then add 2,6-dimethoxyphenylacetic acid ester (26.8 g) prepared in step S2 to the three-necked flask and completely dissolve it, then add 2.8 g (wt%≈10%) of the heteropolyacid supported catalyst prepared above, and react at a temperature of 25°C for 20 hours to obtain a crude product;

[0097] S5: Filter the crude product prepared in step S4, pour the reaction solution obtained after filtration into a saturated NaOH solution and stir, then stand for stratification, take the upper aqueous phase, add HCl to adjust the pH to 4.8, add ethyl acetate to extract three times, combine the organic phases extracted three times, evaporate to dryness, and obtain acetosyringone. The mass spectrum result of the acetosyringone is as follows: Figure 1 shown.

[0098] Example 2

[0099] The difference from Example 1 is that the trifluoromethanesulfonate in the heteropolyacid-supported catalyst is Cu(OTf)2, the amount of 2,6-dimethoxyphenylacetate used in step S4 is 30.6 g, and the amount of the heteropolyacid-supported catalyst used is 3.1 g.

[0100] Example 3

[0101] The difference from Example 1 is that the trifluoromethanesulfonate in the heteropolyacid-supported catalyst is La(OTf)3, the amount of 2,6-dimethoxyphenylacetate used in step S4 is 28.9 g, and the amount of the heteropolyacid-supported catalyst used is 2.9 g.

[0102] Example 4

[0103] The difference from Example 1 is that the trifluoromethanesulfonate in the heteropolyacid supported catalyst is Mn(OTf)2, the amount of 2,6-dimethoxyphenylacetate used in step S4 is 27.5 g, and the amount of the heteropolyacid supported catalyst used is 2.7 g.

[0104] Example 5

[0105] The difference from Example 1 is that the trifluoromethanesulfonate in the heteropolyacid supported catalyst is Sn(OTf)2, the amount of 2,6-dimethoxyphenylacetate used in step S4 is 32.4 g, and the amount of the heteropolyacid supported catalyst used is 3.4 g.

[0106] Example 6

[0107] The difference from Example 1 is that the trifluoromethanesulfonate in the heteropolyacid-supported catalyst is Tb(OTf)3, the amount of 2,6-dimethoxyphenylacetate used in step S4 is 30.8 g, and the amount of the heteropolyacid-supported catalyst used is 2.9 g.

[0108] Comparative Example 1

[0109] The difference from Example 1 is that the heteropolyacid supported catalyst is replaced by phosphotungstic acid.

[0110] Comparative Example 2

[0111] The difference from Example 1 is that the heteropolyacid supported catalyst is replaced by trifluoromethanesulfonate Bi(OTf)3.

[0112] Comparative Example 3

[0113] The difference from Example 1 is that the amount of the heteropolyacid supported catalyst used is 1 g.

[0114] Comparative Example 4

[0115] The difference from Example 1 is that the mixed solution obtained in step S1 is directly recrystallized.

[0116] The purity and conversion rate of the acetosyringone prepared in the above examples and comparative examples were tested, and the specific data are shown in Table 1.

[0117] Table 1 Test data

[0118]

[0119]

[0120] analyze:

[0121] As shown in Table 1, by using acetic anhydride as the acylating agent, adopting a suitable heteropolyacid supported catalyst as the catalyst for the rearrangement of phenol esters, and controlling the reaction conditions, the product can be obtained most efficiently.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0123] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing acetosyringone, characterized in that: include: Ethyl acetate, 2,6-dimethoxyphenol and an acyl compound are mixed and reacted to obtain a first intermediate; The organic solution of the first intermediate and the aqueous phase are mixed, extracted, separated to obtain an organic phase, the organic phase is dried to obtain a solid product, the solid product and ethanol are mixed, and recrystallized to obtain a second intermediate; The second intermediate, the heteropolyacid supported catalyst, and the chlorine-containing organic solvent are mixed, and a second reaction is performed to obtain acetosyringone; The heteropolyacid supported catalyst includes a heteropolyacid carrier and a metal salt disposed on the surface of the heteropolyacid carrier or / and in the pores.

2. The method for preparing acetosyringone according to claim 1, characterized in that: At least one of the following conditions is met: A. The heteropoly acid carrier includes one or more of phosphotungstic acid, phosphomolybdic acid, and silicotungstic acid; B. The metal salt includes one or more of trifluoromethanesulfonate metal salt, non-rare earth transition metal element salt, and rare earth metal salt.

3. The method for preparing acetosyringone according to claim 2, characterized in that: At least one of the following conditions is met: A. The chemical formula of the metal trifluoromethanesulfonate is: M(OTf) X ; Among them, M includes Bi 3+ , Cu 2+ ,La 3+ , Mn 2+ Sn 2+ and Tb 3+ One or more of; B. The metal elements in the non-rare earth transition metal element salt include one or more of Fe, Co, Ni, and Zn.

4. The method for preparing acetosyringone according to claim 1, characterized in that: The mass ratio of the metal salt to the heteropolyacid carrier is 0.8-1.2:

100.

5. The method for preparing acetosyringone according to claim 1, characterized in that: At least one of the following conditions is met: A. the acyl compound comprises one or more of acetic anhydride, acetamide, and butyl acetate; B. The chlorine-containing organic solvent includes one or more of dichloromethane, chloroform, 1,2-dichloroethane, and 1,1,2,2-tetrachloroethane.

6. The method for preparing acetosyringone according to claim 1, characterized in that: At least one of the following conditions is met: A. The molar ratio of the ethyl acetate, the 2,6-dimethoxyphenol, and the acyl compound is 4-4.5:1:1.05-1.4; B. The mass ratio of the second intermediate to the heteropolyacid supported catalyst is 26-33:2.5-3.

5.

7. The method for preparing acetosyringone according to claim 1, characterized in that: At least one of the following conditions is met: A. The temperature of the first reaction is 55°C-60°C and the time is 10h-12h; B. The temperature of the second reaction is 25°C-35°C and the time is 20h-24h.

8. The method for preparing acetosyringone according to any one of claims 1 to 7, characterized in that: At least one of the following conditions is met: A. NaHCO3 solution is also added to the liquid separation; B. after carrying out the second reaction, further carry out post-treatment, the post-treatment comprising: The reactant obtained after the second reaction is subjected to solid-liquid separation to obtain a liquid phase, the liquid phase and an inorganic alkaline compound are mixed, and the aqueous phase is obtained by layering, the aqueous phase and an acidic compound are mixed to obtain an acid-adjusted aqueous phase, the acid-adjusted aqueous phase and ethyl acetate are mixed, and the acetosyringone is extracted.

9. The method for preparing acetosyringone according to claim 8, characterized in that: The pH value of the aqueous phase after acid adjustment is 4.5-5.

10. The method for preparing acetosyringone according to claim 8, characterized in that: At least one of the following conditions is met: A. The inorganic alkaline compound includes one or more of NaOH, KOH, and ammonia water; B. The acidic compound includes an organic acid and / or an inorganic acid.

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