A method for synthesizing m-hydroxybenzoic acid from triacetyl triaminobenzoic acid

Abstract

The application provides a method for synthesizing phloroglucinol from triacetylated triaminobenzoic acid, wherein N,N,N-triacetyl-2,4,6-triaminobenzoic acid is used as raw material, the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is heated in an acidic solution, and a plurality of reactions such as deacetylation, hydrolysis and deacidification are simultaneously realized in one-pot operation to directly obtain phloroglucinol, so that simple, efficient, safe and mild synthesis is realized, and a solid foundation is laid for large-scale preparation of phloroglucinol. The reaction process of the synthesis route produces less by-products, and environmental pollution is reduced.

Description

Technical Field

[0001] This invention relates to the fields of chemical engineering and materials, and mainly to a method for synthesizing phloroglucinol from triacetyltriaminobenzoic acid. Background Technology

[0002] Phloroglucinol is an important antispasmodic drug and is also used as an intermediate in the synthesis of drugs for treating cardiovascular diseases and hepatobiliary diseases such as chronic hepatitis. It also possesses antibacterial, antiviral, and antitumor properties, as well as anti-inflammatory, hemostatic, and uterine-contracting effects, resulting in a large market demand. Furthermore, as a pharmaceutical and chemical raw material and synthetic intermediate, it has important applications in dyeing and rubber synthesis, azo composite inks, plastic capsule production, textile and leather dyeing, and as a substitute for silver iodide in artificial rainmaking. Although phloroglucinol is widely distributed in nature, found in plants, microorganisms, and other organisms, directly isolating it from these natural resources is not an easy task.

[0003] Currently, the methods for synthesizing phloroglucinol include: (1) oxidation of 1,3,5-triisopropylbenzene; (2) hydrolysis of 1,3,5-trihalobenzene; (3) microbial synthesis; and (4) alkaline hydrolysis of dichlorophenol. However, these synthetic routes all have problems such as high cost, low overall yield, long synthetic routes, many by-products, complex separation, high pollution, and difficulty in industrialization.

[0004] Therefore, there is an urgent need in this field for a simple and efficient synthetic route to prepare phloroglucinol, thereby reducing costs and environmental pollution. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for synthesizing phloroglucinol from triacetylated triaminobenzoic acid, achieving a simple, efficient, safe, low-pollution, and low-cost synthesis of phloroglucinol. Details are as follows:

[0006] This invention provides a method for synthesizing phloroglucinol from triacetylated triaminobenzoic acid, the synthesis method comprising:

[0007] Step 1: Using N,N,N-triacetyl-2,4,6-triaminobenzoic acid as shown in structural formula II as the reactant, the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is heated in an acidic solution to obtain the reaction solution;

[0008] Step 2: Crystallize and filter the solution after the reaction to obtain phloroglucinol as shown in structural formula I;

[0009]

[0010] The acidic solution is a sulfuric acid solution, a phosphoric acid solution, a hydrochloric acid solution, an ammonium chloride solution, a trifluoroacetic acid solution, or a methanesulfonic acid solution.

[0011] Optionally, when the acidic solution is a sulfuric acid solution, the mass percentage of sulfuric acid in the sulfuric acid solution is 5-30%;

[0012] The mass ratio of the sulfuric acid solution to the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:1.

[0013] The heating reaction temperature is 40–85°C, and the heating reaction time is 0.5–7 h.

[0014] The crystallization temperature is -1 to 4°C, and the crystallization time is 2 to 8 hours.

[0015] Optionally, when the acidic solution is a phosphoric acid solution, the mass percentage of phosphoric acid in the phosphoric acid solution is 5-45%;

[0016] The mass ratio of the phosphoric acid solution to the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:1.

[0017] The heating reaction temperature is 40–95°C, and the heating reaction time is 0.5–7 h.

[0018] The crystallization temperature is -1 to 4°C, and the crystallization time is 2 to 8 hours.

[0019] Optionally, when the acidic substance is a hydrochloric acid solution, the volume percentage of hydrochloric acid in the hydrochloric acid solution is 5-10%.

[0020] The mass ratio of the hydrochloric acid solution to the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:1.

[0021] The heating reaction temperature is 40–95°C, and the heating reaction time is 0.5–7 h.

[0022] The crystallization temperature is -1 to 4°C, and the crystallization time is 2 to 8 hours.

[0023] Optionally, when the acidic substance is an ammonium chloride solution, the mass percentage of ammonium chloride in the ammonium chloride solution is 5-30%;

[0024] The mass ratio of the ammonium chloride solution to the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:1.

[0025] The heating reaction temperature is 40–95°C, and the heating reaction time is 0.5–7 h.

[0026] The crystallization temperature is -1 to 4°C, and the crystallization time is 2 to 8 hours.

[0027] Optionally, when the acidic substance is a trifluoroacetic acid solution, the mass percentage of trifluoroacetic acid in the trifluoroacetic acid solution is 5-20%.

[0028] The mass ratio of the trifluoroacetic acid solution to the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:1.

[0029] The heating reaction temperature is 40–95°C, and the heating reaction time is 0.5–7 h.

[0030] The crystallization temperature is -1 to 4°C, and the crystallization time is 2 to 8 hours.

[0031] Optionally, when the acidic substance is a methanesulfonic acid solution, the mass percentage of methanesulfonic acid in the methanesulfonic acid solution is 5-20%.

[0032] The mass ratio of the methanesulfonic acid solution to the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:1.

[0033] The heating reaction temperature is 40–95°C, and the heating reaction time is 0.5–10 h;

[0034] The crystallization temperature is -1 to 4°C; the crystallization time is 2 to 8 hours.

[0035] This invention provides a method for synthesizing phloroglucinol. The method uses N,N,N-triacetyl-2,4,6-triaminobenzoic acid as the reactant, reacts it in an acidic aqueous solution under heating, and then crystallizes and filters the resulting solution to obtain phloroglucinol. Compared with the prior art, this invention has at least the following advantages:

[0036] The synthetic route provided by this invention uses N,N,N-triacetyl-2,4,6-triaminobenzoic acid as a raw material, and simultaneously achieves multiple steps such as deacetylation, hydrolysis and deacidification in a one-pot operation. The reaction produces few by-products and causes little environmental pollution. The method is simple to operate, and the solvents and wastewater used can be recycled and treated. It achieves a simple, efficient, safe and mild synthesis, laying a solid foundation for the large-scale preparation of phloroglucinol. Attached Figure Description

[0037] Figure 1 A flowchart of the method for synthesizing phloroglucinol from triacetyltriaminobenzoic acid in an embodiment of the present invention is shown;

[0038] Figure 2The 1H NMR spectrum of N,N,N-triacetyl-2,4,6-triaminobenzoic acid provided in an embodiment of the present invention is shown.

[0039] Figure 3 The carbon NMR spectrum of N,N,N-triacetyl-2,4,6-triaminobenzoic acid provided in an embodiment of the present invention is shown.

[0040] Figure 4 The high-resolution mass spectrum of N,N,N-triacetyl-2,4,6-triaminobenzoic acid provided in the embodiments of the present invention is shown.

[0041] Figure 5 The following is a hydrogen nuclear magnetic resonance spectrum of phloroglucinol provided in an embodiment of the present invention;

[0042] Figure 6 The carbon NMR spectrum of phloroglucinol provided in an embodiment of the present invention is shown.

[0043] Figure 7 The infrared spectrum of phloroglucinol provided in an embodiment of the present invention is shown.

[0044] Figure 8 The high-resolution mass spectrum of phloroglucinol provided in the embodiments of the present invention is shown. Detailed Implementation

[0045] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0046] For experiments not specifically described in the examples, the procedures or conditions should be followed according to conventional experimental procedures described in the prior art. Reagents and other instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0047] This invention provides a method for synthesizing phloroglucinol from triacetylated triaminobenzoic acid. Figure 1 A flowchart illustrating the method for synthesizing phloroglucinol from triacetylated triaminobenzoic acid in an embodiment of the present invention is shown, as follows: Figure 1 As shown, the synthesis method includes:

[0048] S1. Using N,N,N-triacetyl-2,4,6-triaminobenzoic acid as shown in structural formula II as the reactant, the N,N,N-triacetyl-2,4,6-triaminobenzoic acid is heated in an acidic solution to obtain the reaction solution;

[0049] S2. Crystallize and filter the solution after the reaction to obtain phloroglucinol as shown in structural formula I;

[0050]

[0051] The acidic solution is a sulfuric acid solution, phosphoric acid solution, hydrochloric acid solution, ammonium chloride solution, trifluoroacetic acid solution, or methanesulfonic acid solution.

[0052] In specific implementation, N,N,N-triacetyl-2,4,6-triaminobenzoic acid (Structure II) with a mass ratio of 10:1 to 4:1 is mixed with an acidic solution and reacted continuously at a heating temperature of 40 to 95°C for 0.5 to 7 hours to finally obtain the transformation process of phloroglucinol (Structure I). This process involves multiple intermediates and functional group transformations.

[0053] First, the acetyl functional group in N,N,N-triacetyl-2,4,6-triaminobenzoic acid can be deacetylated under both acidic and alkaline conditions, releasing the original amino functional group. The specific acid or alkaline strength depends on the substrate structure. After extensive experimental research, this invention discovered that N,N,N-triacetyl-2,4,6-triaminobenzoic acid can be deacetylated under heating conditions at pH < 5, yielding a triaminobenzoic acid intermediate. However, due to the heating time and the continuity of the intermediate reaction, the production of triaminobenzoic acid was not directly observed in the intermediate product; instead, the presence of the intermediate trihydroxybenzoic acid was observed. The inventors interpret this phenomenon as follows: the polyaminobenzene ring undergoes isomerization in acidic solution, transforming from a free amino structure to an imine-enamine structure. The resulting imine-enamine structure undergoes an exchange reaction with water under high temperature, and the deacetylated amino group is captured by the acidic environment to form an ammonium salt compound, thus escaping the reaction. This process occurs almost simultaneously with the deprotection process of deacetylation protection, so the presence of triaminobenzoic acid as an intermediate is not observed; instead, trihydroxybenzoic acid is directly observed.

[0054] Furthermore, due to its unstable structure, trihydroxybenzoic acid can spontaneously detach one mole of CO2 in an acidic solution environment and transform into phloroglucinol. Heating accelerates this forward reaction. During the overall reaction process, timed observation of the products revealed that in the initial stage, the products consisted predominantly of triaminobenzoic acid and the reactant N,N,N-triacetyl-2,4,6-triaminobenzoic acid. As the reaction progressed, in the intermediate stage, the products were a mixture of trihydroxybenzoic acid and phloroglucinol. Finally, as the reaction entered the final stage, only phloroglucinol remained as the final product.

[0055]

[0056] The above reaction process can be understood as follows: N,N,N-triacetyl-2,4,6-triaminobenzoic acid, when heated in an acidic environment, first undergoes deacetylation to generate the first intermediate, triaminobenzoic acid. Due to continued heating and the presence of the acidic environment, the amino group in triaminobenzoic acid undergoes an isomerization transformation from a free amino structure to an imine-enamine structure. The transformed imine-enamine structure undergoes an exchange reaction with water at high temperature, thereby removing the amino group and converting the first intermediate, triaminobenzoic acid, into the second intermediate, trihydroxybenzoic acid. The removed amino group is captured by the acidic environment to form an ammonium salt compound, thus escaping the reaction. When the second intermediate, trihydroxybenzoic acid, is further heated in an acidic environment, the carboxyl group releases a mole of CO2, transforming into phloroglucinol.

[0057] Furthermore, since the target product, phloroglucinol, is a polyhydroxy compound with strong hydrophilicity, it is difficult for it to form a crystal lattice, especially under heating conditions. This poses challenges for the separation and collection of the target product from the post-reaction solution. This invention involves cooling the post-reaction solution. Under low-temperature conditions, the target product, phloroglucinol, gradually forms a crystal lattice and crystallizes, precipitating from the post-reaction solution. Specifically, the cooling temperature is maintained between -1 and 4°C, and the crystallization time is controlled between 2 and 8 hours. Further filtration of the crystallized target product allows for simple and efficient collection, achieving a 100% recovery rate.

[0058] The method for synthesizing resorcinol from triacetylated triaminobenzoic acid provided in this invention uses N,N,N-triacetyl-2,4,6-triaminobenzoic acid as the reactant. It innovatively achieves multiple steps of deacetylation, hydrolysis, and deacidification of N,N,N-triacetyl-2,4,6-triaminobenzoic acid in a one-pot operation without changing the reaction conditions (continuous heating in an acidic environment). Specifically, in a one-pot operation, triaminobenzoic acid and trihydroxybenzoic acid are successively converted, with trihydroxybenzoic acid ultimately completing the conversion to resorcinol. This one-step experimental design yields resorcinol, achieving a simple, efficient, safe, and mild synthesis. It can significantly reduce the time and economic costs required for the synthesis of resorcinol, laying a solid foundation for the large-scale preparation of resorcinol. This synthetic route produces fewer byproducts during the reaction process, reducing environmental pollution.

[0059] In some embodiments, when the acidic solution used in the reaction is sulfuric acid, the mass percentage of sulfuric acid in the solution is controlled at 5-30%. This sulfuric acid solution can be diluted with water or ethyl acetate. Furthermore, the mass ratio of the dilute sulfuric acid solution to the reactant N,N,N-triacetyl-2,4,6-triaminobenzoic acid is controlled at 10:1-4:1 to ensure the weakly acidic environment required for the reaction to proceed normally. Additionally, the heating temperature of the N,N,N-triacetyl-2,4,6-triaminobenzoic acid reaction in the sulfuric acid solution is controlled at 40-85°C, and the time is controlled at 0.5-7 hours. This allows for control of a high yield of phloroglucinol and a low content of byproducts.

[0060] Furthermore, in the process of collecting the target product phloroglucinol from the solution after the reaction, the crystallization of phloroglucinol was carried out at a low temperature of -1 to 4°C, and the crystallization time was controlled within 2 to 8 hours.

[0061] In some embodiments, when the acidic solution used in the reaction is a phosphoric acid solution, the mass percentage of phosphoric acid in the phosphoric acid solution is controlled at 5-30%. This phosphoric acid solution can be diluted with water or ethyl acetate. Furthermore, the mass ratio between the amount of dilute phosphoric acid solution and the reactant N,N,N-triacetyl-2,4,6-triaminobenzoic acid is controlled at 10:1-4:1 to ensure the weakly acidic environment required for the normal reaction. Additionally, the heating temperature of N,N,N-triacetyl-2,4,6-triaminobenzoic acid in the phosphoric acid solution is controlled at 40-95°C, and the time is controlled at 0.5-7 hours. This allows for control of a high yield of phloroglucinol and a low content of byproducts.

[0062] Furthermore, in the process of collecting the target product phloroglucinol from the solution after the reaction, the crystallization of phloroglucinol was carried out at a low temperature of -1 to 4°C, and the crystallization time was controlled within 2 to 8 hours.

[0063] In some embodiments, when the acidic solution used in the reaction is hydrochloric acid, the mass percentage of hydrochloric acid in the solution is controlled at 5-10%. This hydrochloric acid solution can be diluted with water or ethyl acetate. Furthermore, the mass ratio of the dilute hydrochloric acid solution to the reactant N,N,N-triacetyl-2,4,6-triaminobenzoic acid is controlled at 10:1-4:1 to ensure the weakly acidic environment required for the reaction to proceed normally. Additionally, the heating temperature of the N,N,N-triacetyl-2,4,6-triaminobenzoic acid reaction in the hydrochloric acid solution is controlled at 40-95°C, and the time is controlled at 0.5-7 hours. This allows for control of a high yield of phloroglucinol and a low content of byproducts.

[0064] Furthermore, in the process of collecting the target product phloroglucinol from the solution after the reaction, the crystallization of phloroglucinol was carried out at a low temperature of -1 to 4°C, and the crystallization time was controlled within 2 to 8 hours.

[0065] In some embodiments, when the acidic solution used in the reaction is an ammonium chloride solution, the mass percentage of ammonium chloride in the ammonium chloride solution is controlled at 5-30%. This ammonium chloride solution can be diluted with water or ethyl acetate. Furthermore, the mass ratio of the ammonium chloride solution to the reactant N,N,N-triacetyl-2,4,6-triaminobenzoic acid is controlled at 10:1-4:1 to ensure the weakly acidic environment required for the normal reaction. Additionally, the heating temperature of the N,N,N-triacetyl-2,4,6-triaminobenzoic acid reaction in the ammonium chloride solution is controlled at 40-95°C, and the time is controlled at 0.5-7 hours. This allows for control of a high yield of phloroglucinol and a low content of byproducts.

[0066] Furthermore, in the process of collecting the target product phloroglucinol from the solution after the reaction, the crystallization of phloroglucinol was carried out at a low temperature of -1 to 4°C, and the crystallization time was controlled within 2 to 8 hours.

[0067] In some embodiments, when the acidic solution used in the reaction is a trifluoroacetic acid solution, the mass percentage of trifluoroacetic acid in the solution is controlled at 5-30%. This trifluoroacetic acid solution can be diluted with water or ethyl acetate. Furthermore, the mass ratio between the amount of dilute trifluoroacetic acid solution and the reactant N,N,N-triacetyl-2,4,6-triaminobenzoic acid is controlled at 10:1-4:1 to ensure the weakly acidic environment required for the normal reaction. Additionally, the heating temperature of N,N,N-triacetyl-2,4,6-triaminobenzoic acid in the trifluoroacetic acid solution is controlled at 40-95°C, and the time is controlled at 0.5-7 hours. This allows for control of a high yield of phloroglucinol and a low content of byproducts.

[0068] Furthermore, in the process of collecting the target product phloroglucinol from the solution after the reaction, the crystallization of phloroglucinol was carried out at a low temperature of -1 to 4°C, and the crystallization time was controlled within 2 to 8 hours.

[0069] In some embodiments, when the acidic solution used in the reaction is a methanesulfonic acid solution, the mass percentage of methanesulfonic acid in the methanesulfonic acid solution is controlled at 5-30%. This methanesulfonic acid solution can be diluted with water or ethyl acetate, and the mass ratio between the amount of dilute methanesulfonic acid solution and the reactant N,N,N-triacetyl-2,4,6-triaminobenzoic acid is controlled at 10:1-4:1 to ensure the weakly acidic environment required for the normal reaction. Furthermore, the heating temperature of N,N,N-triacetyl-2,4,6-triaminobenzoic acid in the methanesulfonic acid solution is controlled at 40-85°C, and the time is controlled at 0.5-7 hours. This allows for control of a high yield of phloroglucinol and a low content of byproducts.

[0070] Furthermore, in the process of collecting the target product phloroglucinol from the solution after the reaction, the crystallization of phloroglucinol was carried out at a low temperature of -1 to 4°C, and the crystallization time was controlled within 2 to 8 hours.

[0071] It should be noted that the reaction raw material N,N,N-triacetyl-2,4,6-triaminobenzoic acid used in the embodiments of the present invention can be derived from the intermediate product in the preparation of the insensitive explosive TATB disclosed in CN 111995527 A. Specifically, the method for obtaining it is as follows: 2,4,6-trinitrotoluene undergoes hydrogen reduction, in-situ acylation with acetic anhydride, and oxidation to obtain N,N,N-triacetyl-2,4,6-triaminobenzoic acid. Specifically, 2,4,6-trinitrotoluene undergoes hydrogen reduction to obtain 2,4,6-triaminotoluene; 2,4,6-triaminotoluene undergoes in-situ acylation with acetic anhydride to obtain 2,4,6-triacetaminotoluene; and 2,4,6-triacetaminotoluene undergoes oxidation to obtain N,N,N-triacetyl-2,4,6-triaminobenzoic acid. The oxidizing agent can be potassium permanganate or potassium dichromate.

[0072] For example, 2,4,6-trinitrotoluene I (TNT) was completely dissolved in ethyl acetate in a reactor. A certain mass of Pd / C catalyst was added, the reactor was evacuated, and nitrogen was purged. This process was repeated several times, and finally, the reactor was evacuated again to ensure no air residue remained. The mixture was stirred on a magnetic stirrer, and hydrogen was introduced to continue the reaction. After the reaction was completed, the Pd / C catalyst was filtered off to obtain a 2,4,6-triaminotoluene solution. Acetic anhydride was added dropwise to the 2,4,6-triaminotoluene solution under stirring to carry out an acylation reaction. A large amount of flocculent precipitate appeared in the reaction system. After filtration, the precipitate was washed and dried to obtain 2,4,6-triacetaminotoluene. The 2,4,6-triacetaminotoluene solution was added dropwise to a potassium permanganate oxidant system to carry out an oxidation reaction to obtain N,N,N-triacetyl-2,4,6-triaminobenzoic acid. Figure 2 The 1H NMR spectrum of N,N,N-triacetyl-2,4,6-triaminobenzoic acid provided in an embodiment of the present invention is shown. Figure 3 The carbon NMR spectrum of N,N,N-triacetyl-2,4,6-triaminobenzoic acid provided in an embodiment of the present invention is shown. Figure 4 The high-resolution mass spectrum of N,N,N-triacetyl-2,4,6-triaminobenzoic acid provided in the embodiments of the present invention is shown.

[0073] To enable those skilled in the art to better understand the present invention, the following specific embodiments illustrate a method for synthesizing phloroglucinol from triacetyltriaminobenzoic acid provided by the present invention.

[0074] Example 1

[0075] N,N,N-Triacetyl-2,4,6-triaminobenzoic acid (100 mmol, 29.3 g) was dispersed in 130 g of 5% sulfuric acid (6.5 g, 123.5 g deionized water), and heated to 85 °C for 1 hour until all reactants were completely dissolved in the solution. After the reaction was complete, the resulting solution was placed in a freezer at -1 °C to cool and crystallize. The solid product, phloroglucinol I (11.6 g, 97%), was collected by filtration. The solvent used was recovered by rotary evaporation and reused in other batches of the reaction.

[0076] Figure 5 The following is a hydrogen nuclear magnetic resonance spectrum of phloroglucinol provided in an embodiment of the present invention. Figure 6 The carbon NMR spectrum of phloroglucinol provided in an embodiment of the present invention is shown. Figure 7 The infrared spectrum of phloroglucinol provided in an embodiment of the present invention is shown. Figure 8 The high-resolution mass spectrum of phloroglucinol provided in the embodiments of the present invention is shown.

[0077] 1H NMR spectrum: 1 H-NMR(400MHz,DMSO-D6)δ(ppm):8.95,5.67.

[0078] Carbon NMR spectrum: 13 C-NMR(101MHz,DMSO-D6)δ(ppm):159.38,94.55.

[0079] Infrared spectrum: 3208 cm⁻¹ -1 1621cm -1 1504cm -1 1415cm -1 1331cm -1 1298cm -1 1153cm -1 1006cm -1 997cm -1 813cm-1 799cm -1 666cm -1 579cm -1 518cm -1 .

[0080] High-resolution mass spectrum: HR-MS (ESI): 125.024444 [MH]-(C6H5O3, required 125.024418).

[0081] Example 2

[0082] The implementation content of this embodiment is similar to that of Embodiment 1 above, except that the acidic solution used is a 5% (w / w) dilute ethyl phosphate solution.

[0083] Example 3

[0084] The implementation content of this embodiment is similar to that of Embodiment 1 above, except that the acidic solution used is a 5% volume fraction of dilute hydrochloric acid ethyl acetate solution.

[0085] Example 4

[0086] The implementation content of this embodiment is similar to that of Embodiment 1 above, except that the acidic solution used is a 30% mass fraction ammonium chloride aqueous solution.

[0087] Example 5

[0088] The implementation content of this embodiment is similar to that of Embodiment 1 above, except that the acidic solution used is a 10% (w / w) aqueous solution of methanesulfonic acid.

[0089] In Examples 2-5 above, the 1H NMR spectrum, 1C NMR spectrum, IR spectrum, and high-resolution mass spectrum of the target product phloroglucinol obtained are respectively compared with those of the attached... Figure 5-8 The same applies, and will not be repeated in Examples 2-5.

[0090] It should be noted that the steps and methods in the various embodiments of this application are not limited to the corresponding embodiments, and the operational details and precautions of each embodiment are corresponding to each other.

[0091] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0092] The above provides a detailed description of a method for synthesizing phloroglucinol from triacetyltriaminobenzoic acid provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above examples is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for synthesizing phloroglucinol from triacetylated triaminobenzoic acid, characterized in that, The synthesis method includes: Step 1: Using N´,N´´,N´´´-triacetyl-2,4,6-triaminobenzoic acid as shown in structural formula II as the reactant, the N´,N´´,N´´´-triacetyl-2,4,6-triaminobenzoic acid is heated in an acidic solution to obtain the reaction solution; Step 2: Crystallize and filter the solution after the reaction to obtain phloroglucinol as shown in structural formula I; The acidic solution is a sulfuric acid solution, a phosphoric acid solution, a hydrochloric acid solution, an ammonium chloride solution, a trifluoroacetic acid solution, or a methanesulfonic acid solution; The heating reaction temperature is 40–85°C, and the heating reaction time is 0.5–7 h. The crystallization temperature is -1 to 4°C, and the crystallization time is 2 to 8 hours.

2. The method according to claim 1, characterized in that, When the acidic solution is a sulfuric acid solution, the mass percentage of sulfuric acid in the sulfuric acid solution is 5-30%; The mass ratio of the sulfuric acid solution to the N´,N´´,N´´´-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:

1.

3. The method according to claim 1, characterized in that, When the acidic solution is a phosphoric acid solution, the mass percentage of phosphoric acid in the phosphoric acid solution is 5-45%; The mass ratio of the phosphoric acid solution to the N´,N´´,N´´´-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:

1.

4. The method according to claim 1, characterized in that, When the acidic substance is a hydrochloric acid solution, the volume percentage of hydrochloric acid in the hydrochloric acid solution is 5-10%. The mass ratio of the hydrochloric acid solution to the N´,N´´,N´´´-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:

1.

5. The method according to claim 1, characterized in that, When the acidic substance is an ammonium chloride solution, the mass percentage of ammonium chloride in the ammonium chloride solution is 5-30%; The mass ratio of the ammonium chloride solution to the N´,N´´,N´´´-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:

1.

6. The method according to claim 1, characterized in that, When the acidic substance is a trifluoroacetic acid solution, the mass percentage of trifluoroacetic acid in the trifluoroacetic acid solution is 5-20%. The mass ratio of the trifluoroacetic acid solution to the N´,N´´,N´´´-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:

1.

7. The method according to claim 1, characterized in that, When the acidic substance is a methanesulfonic acid solution, the mass percentage of methanesulfonic acid in the methanesulfonic acid solution is 5-20%. The mass ratio of the methanesulfonic acid solution to the N´,N´´,N´´´-triacetyl-2,4,6-triaminobenzoic acid is 10:1 to 4:1.

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