A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran

Abstract

The present invention belongs to the technical field of biomass catalytic conversion, and specifically relates to a method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran. Aiming at the problems existing in the existing reaction for preparing 3-acetamido-5-acetylfuran, such as the cumbersome reaction process, the complex and costly catalyst preparation process, and environmental pollution, etc., in this method, arginine or proline is used as a hydrogen bond acceptor, and alcohols such as glycerol and acids such as lactic acid are used as hydrogen bond donors to prepare a natural deep eutectic solvent by heating and stirring at a certain temperature. Then, D-glucosamine is fully stirred and mixed with the natural deep eutectic solvent, and the reaction is carried out at a certain temperature and normal pressure. Finally, the crude product after the reaction is filtered, extracted, rotary evaporated, and crystallized to obtain pure 3-acetamido-5-acetylfuran. This method uses the natural deep eutectic solvent as the reaction solvent and catalyst, and can achieve the directional synthesis of 3-acetamido-5-acetylfuran without introducing other co-solvents and co-catalysts.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass catalytic conversion, and particularly relates to a method for preparing a nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran. Background Art

[0002] Nitrogen-containing chemicals are widely used in the fields of food, medicine, chemical industry, etc., and the market demand is huge. Taking the typical nitrogen-containing fine chemical 3-acetamido-5-acetylfuran as an example, it is widely used in the pharmaceutical and chemical fields due to its unique chemical structure and biological properties. For example, the anti-cancer drug Proximicin A contains the 3-acetamido-5-acetylfuran structural unit. However, the traditional preparation of nitrogen-containing chemicals relies on the Haber reaction, which has high energy consumption and harsh reaction conditions during the reaction process. In addition, it is difficult to introduce a nitrogen-containing group at the C3 position of the furan ring in the traditional preparation route, so the preparation of 3-acetamido-5-acetylfuran is relatively difficult. Therefore, it is particularly important to explore a green and efficient preparation route for 3-acetamido-5-acetylfuran.

[0003] At present, researchers are gradually deepening the research on the preparation of 3-acetamido-5-acetylfuran from biomass resources chitin and its monomer D-glucosamine through biomass conversion. Chitin, as the second largest biomass resource after cellulose, has a large reserve and is relatively easy to obtain. Its unique biological nitrogen fixation amount reaches 7wt%, which is an ideal nitrogen source. Converting it into nitrogen-containing fine chemicals can not only achieve the dual goals of carbon fixation and nitrogen fixation, but also provide a feasible solution for the sustainable utilization of marine resources and the efficient treatment of marine garbage, meeting the requirements of green chemistry and atom economy. In previous literature reports, Omari et al. used boric acid and sodium chloride as catalysts to convert D-glucosamine into 3-acetamido-5-acetylfuran by microwave heating at 220°C; Yan et al. used imidazolium ionic liquid and boric acid to catalyze the conversion of D-glucosamine into 3-acetamido-5-acetylfuran; Zang et al. used amino acid ionic liquid, ethanolamine ionic liquid, pyridyl ionic liquid, pyrazinyl ionic liquid, etc. to catalyze the conversion of D-glucosamine into 3-acetamido-5-acetylfuran. Chen et al. used choline chloride-based deep eutectic solvent, ammonium chloride, and bio-enzymatic-chemical method to catalyze the preparation of 3-acetamido-5-acetylfuran from D-glucosamine.

[0004] Analysis of the currently reported preparation routes of 3-acetamido-5-acetylfuran reveals that these methods mostly use ionic liquids as catalysts or react under high temperature and pressure. In addition, there are also bio-chemical catalysis methods. There are problems such as complex preparation of ionic liquid catalysts, high costs, and difficulty in large-scale application; harsh reaction conditions, lack of green environmental protection; low catalytic efficiency, poor reaction selectivity, and low yield. Therefore, exploring an efficient and green route for the conversion of D-glucosamine to 3-acetamido-5-acetylfuran has profound scientific significance and broad application prospects. Summary of the Invention

[0005] Aiming at the problems existing in the existing reaction for the preparation of 3-acetamido-5-acetylfuran, such as cumbersome reaction process, complex and costly catalyst preparation process, and environmental pollution, the present invention provides a method for catalytically preparing 3-acetamido-5-acetylfuran using a ternary natural deep eutectic solvent.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0008] Step 1: Stir D-glucosamine and a ternary natural deep eutectic solvent at room temperature and mix them evenly to obtain a mixed solution, wherein the ternary natural deep eutectic solvent includes a hydrogen bond acceptor, an alcohol hydrogen bond donor, and an acid hydrogen bond donor. The hydrogen bond acceptor is a natural component, proline or arginine. The alcohol hydrogen bond donor is any one of glycerol, ethylene glycol, 1,3-butanediol, and 1,4-butanediol. The acid hydrogen bond donor is one of lactic acid, formic acid, acetic acid, malic acid, and citric acid;

[0009] Step 2: Heat and stir the mixed solution to generate a mixed liquid containing the crude product of 3-acetamido-5-acetylfuran;

[0010] Step 3: Filter the mixed liquid containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract and remove the extractant by vacuum distillation, and then crystallize in cold water to obtain the product 3-acetamido-5-acetylfuran.

[0011] Furthermore, the D-glucosamine in Step 1 is derived from the natural nitrogen-containing biomass chitin, which is rich in reserves in nature and is relatively easy to obtain. At the same time, using D-glucosamine as the raw material, the reaction is faster and the conversion rate is higher.

[0012] Furthermore, the preparation method of the ternary natural deep eutectic solvent in Step 1 is as follows:

[0013] The hydrogen bond acceptor, alcohol hydrogen bond donor, and acid hydrogen bond donor are stirred and heated at 80 °C to form a colorless transparent liquid, and then dried at 50 °C to obtain a ternary natural deep eutectic solvent. Compared with ionic liquids catalyzing this reaction, natural deep eutectic solvents are formed by hydrogen bond donors and hydrogen bond acceptors through intermolecular hydrogen bonding, are simple to prepare, have low costs, and are easy to use on a large scale. In addition, all components of natural deep eutectic solvents are natural ingredients, the reaction is relatively green, and the post-treatment is simple.

[0014] Furthermore, the molar ratio of the hydrogen bond acceptor, alcohol hydrogen bond donor, and acid hydrogen bond donor is 1:5:0.5 - 2. For example, proline: glycerol: lactic acid = 1:5:0.5 - 2; proline: glycerol: malic acid = 1:5:0.5 - 2; proline: ethylene glycol: formic acid = 1:5:0.5 - 2; proline: 1,3-butanediol: acetic acid = 1:5:0.5 - 2; proline: 1,4-butanediol: citric acid = 1:5:0.5 - 2; arginine: glycerol: lactic acid = 1:5:0.5 - 2; arginine: ethylene glycol: formic acid = 1:5:0.5 - 2; arginine: 1,3-butanediol: malic acid = 1:5:0.5 - 2; arginine: 1,4-butanediol: acetic acid = 1:5:0.5 - 2; arginine: glycerol: citric acid = 1:5:0.5 - 2, etc. The introduction of acid substances has an obvious promoting effect on the reaction of D-glucosamine, but too much introduction of acid will cause the reaction to be too violent, dehydrating to form a solid by-product, humin. Therefore, it is necessary to optimize the ratio of acid substances to hydrogen bond donors in natural deep eutectic solvents. Within this ratio range, the catalytic effect of natural deep eutectic solvents is excellent, the reaction can be more complete, and the yield of 3-acetamido-5-acetylfuran is significantly increased. In addition, natural deep eutectic solvents play a dual role of reaction solvent and catalyst in the reaction, and the reaction can occur without introducing other solvents and co-catalysts, and the reaction process is green and efficient.

[0015] Furthermore, the mass ratio of D-glucosamine to the ternary natural deep eutectic solvent in step 1 is 1:20. At this ratio, the reaction of D-glucosamine is relatively complete, and the selectivity and yield of the product are good.

[0016] Furthermore, the heating temperature in step 2 is 100 °C - 140 °C, the time is 0.5 h - 2 h, and the pressure is normal pressure. Within this reaction temperature and reaction time range, the reaction energy consumption is small, D-glucosamine can react completely, and the yield of 3-acetamido-5-acetylfuran is relatively high.

[0017] Furthermore, in step 3, extraction is carried out using a water-ethyl acetate mixed solvent, and the volume ratio of water to ethyl acetate is 1:5. The extraction speed is fast and the separation effect is good using this mixed solvent. The temperature for vacuum distillation is 60 °C.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) D - Glucosamine, as a monomer source of chitin - like biomass, is widely available, rich in reserves, and relatively easy to obtain. Converting and utilizing it to prepare high - value - added compounds has broad prospects. The present invention uses natural deep eutectic solvents to catalyze the preparation of 3 - acetamido - 5 - acetylfuran, and its production process has potential application value. At the same time, it realizes the dual goals of carbon fixation and nitrogen fixation, meeting the requirements of green chemistry.

[0020] (2) The target product of the present invention, 3 - acetamido - 5 - acetylfuran, is a nitrogen - containing heterocyclic compound with high added value. As an important nitrogen - containing furan intermediate, 3 - acetamido - 5 - acetylfuran is the parent structure of many drug molecules. For example, the anticancer drug Proximicin A contains the 3 - acetamido - 5 - acetylfuran structural unit, showing broad application prospects.

[0021] (3) The present invention uses ternary natural deep eutectic solvents, whose components are from natural ingredients, are green, non - toxic, simple to prepare, low in cost, and easy to post - process. The catalytic effect can be improved by simple design of natural deep eutectic solvent components and optimization of proportions.

[0022] (4) Natural deep eutectic solvents act as both reaction solvents and catalysts in the reaction. The directional synthesis of 3 - acetamido - 5 - acetylfuran can be achieved without introducing other solvents and co - catalysts, and the reaction process is efficient and green.

[0023] (5) The operation of the present invention is simple, the reaction conditions are mild, the reaction can occur at 100 - 140 °C under normal pressure, and the yield of the target product is high. Brief Description of the Drawings

[0024] Figure 1 is the 1 1H nuclear magnetic resonance spectrum of the product 3 - acetamido - 5 - acetylfuran of the present invention. Detailed Embodiments

[0025] In order to further illustrate the technical solution of the present invention, the present invention will be further described below through examples.

[0026] Example 1

[0027] A method for preparing the nitrogen - containing heterocyclic compound 3 - acetamido - 5 - acetylfuran, comprising the following steps:

[0028] Step 1: Mix the hydrogen bond acceptor proline, the alcohol hydrogen bond donor ethylene glycol, and the acid hydrogen bond donor formic acid in a molar ratio of 1:5:0.5, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural deep eutectic solvent, and then place it in a vacuum drying oven and dry at 50 °C for 24 h for standby;

[0029] Step 2: Weigh 1 g of D - glucosamine and 20 g of the natural deep eutectic solvent in a reaction vessel, stir, and mix evenly;

[0030] Step 3: Place the reaction vessel in an oil bath and heat and stir under normal pressure, set the reaction temperature to 100 °C, and the reaction time to 0.5 h. After the reaction, quickly cool the reaction solution in cold water to quench the reaction, generating a mixed solution containing the crude product of 3 - acetamido - 5 - acetylfuran;

[0031] Step 4: Filter the mixed solution containing the crude product of 3 - acetamido - 5 - acetylfuran to remove insoluble impurities, extract it three times with a water - ethyl acetate (volume ratio 1:5) mixed solvent, and then distill off the solvent under reduced pressure in a rotary evaporator and crystallize it in cold water to obtain 3 - acetamido - 5 - acetylfuran ( 1 The \(^1H\) nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic resonance technology, the yield of 3 - acetamido - 5 - acetylfuran is 54%.

[0032] Example 2

[0033] A method for preparing the nitrogen - containing heterocyclic compound 3 - acetamido - 5 - acetylfuran, comprising the following steps:

[0034] Step 1: Mix the hydrogen bond acceptor proline, the alcohol hydrogen bond donor glycerol, and the acid hydrogen bond donor lactic acid in a molar ratio of 1:5:1, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural deep eutectic solvent, and then place it in a vacuum drying oven and dry at 50 °C for 24 h for standby;

[0035] Step 2: Weigh 1 g of D - glucosamine and 20 g of the natural deep eutectic solvent in a reaction vessel, stir, and mix evenly;

[0036] Step 3: Place the reaction vessel in an oil bath and heat and stir under normal pressure, set the reaction temperature to 110 °C, and the reaction time to 1.5 h. After the reaction, quickly cool the reaction solution in cold water to quench the reaction, generating a mixed solution containing the crude product of 3 - acetamido - 5 - acetylfuran;

[0037] Step 4: Filter the mixture containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract it three times with a mixed solvent of water-ethyl acetate (volume ratio 1:5), then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize it in cold water to obtain 3-acetamido-5-acetylfuran ( 1 The \(^1\)H nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic resonance technology, the yield of 3-acetamido-5-acetylfuran is 61%.

[0038] Example 3

[0039] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0040] Step 1: Mix the hydrogen bond acceptor proline, the alcohol hydrogen bond donor 1,3-butanediol, and the acid hydrogen bond donor acetic acid in a molar ratio of 1:5:2, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural deep eutectic solvent, and then place it in a vacuum drying oven and dry it at 50 °C for 24 h for standby;

[0041] Step 2: Weigh 1 g of D-acetamido glucose and 20 g of the natural deep eutectic solvent in a reaction vessel, stir, and mix evenly;

[0042] Step 3: Place the reaction vessel in an oil bath and heat and stir it under normal pressure, set the reaction temperature to 120 °C, and the reaction time to 1 h. After the reaction is completed, quickly cool the reaction solution in cold water to quench the reaction, and generate a mixture containing the crude product of 3-acetamido-5-acetylfuran;

[0043] Step 4: Filter the mixture containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract it three times with a mixed solvent of water-ethyl acetate (volume ratio 1:5), then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize it in cold water to obtain 3-acetamido-5-acetylfuran ( 1 The \(^1\)H nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic resonance technology, the yield of 3-acetamido-5-acetylfuran is 52%.

[0044] Example 4

[0045] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0046] Step 1: Mix the hydrogen bond acceptor proline, the alcohol hydrogen bond donor 1,4-butanediol, and the acid hydrogen bond donor citric acid in a molar ratio of 1:5:1, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural eutectic solvent. Then place it in a vacuum drying oven and dry at 50 °C for 24 h for standby;

[0047] Step 2: Weigh 1 g of D-acetylglucosamine and 20 g of the natural eutectic solvent in a reaction vessel, stir, and mix evenly;

[0048] Step 3: Place the reaction vessel in an oil bath and heat and stir under normal pressure. Set the reaction temperature to 130 °C and the reaction time to 1.5 h. After the reaction is completed, quickly cool the reaction solution in cold water to quench the reaction, generating a mixed solution containing the crude product of 3-acetamido-5-acetylfuran;

[0049] Step 4: Filter the mixed solution containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract it three times with a water-ethyl acetate (volume ratio 1:5) mixed solvent, then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize in cold water to obtain 3-acetamido-5-acetylfuran ( 1 The 1H nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic technology, the yield of 3-acetamido-5-acetylfuran is 55%.

[0050] Example 5

[0051] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0052] Step 1: Mix the hydrogen bond acceptor proline, the alcohol hydrogen bond donor glycerol, and the acid hydrogen bond donor malic acid in a molar ratio of 1:5:0.5, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural eutectic solvent. Then place it in a vacuum drying oven and dry at 50 °C for 24 h for standby;

[0053] Step 2: Weigh 1 g of D-acetylglucosamine and 20 g of the natural eutectic solvent in a reaction vessel, stir, and mix evenly;

[0054] Step 3: Place the reaction vessel in an oil bath and heat and stir under normal pressure. Set the reaction temperature to 140 °C and the reaction time to 2 h. After the reaction is completed, quickly cool the reaction solution in cold water to quench the reaction, generating a mixed solution containing the crude product of 3-acetamido-5-acetylfuran;

[0055] Step 4: Filter the mixture containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract it three times with a water-ethyl acetate (volume ratio 1:5) mixed solvent, then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize it in cold water to obtain 3-acetamido-5-acetylfuran ( 1 The \(^1H\) nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic resonance technology, the yield of 3-acetamido-5-acetylfuran is 49%.

[0056] Example 6

[0057] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0058] Step 1: Mix the hydrogen bond acceptor arginine, the alcohol hydrogen bond donor glycerol, and the acid hydrogen bond donor lactic acid in a molar ratio of 1:5:1, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural eutectic solvent, and then place it in a vacuum drying oven and dry it at 50 °C for 24 h for standby;

[0059] Step 2: Weigh 1 g of D-acetamido glucose and 20 g of the natural eutectic solvent in a reaction vessel, stir, and mix evenly;

[0060] Step 3: Place the reaction vessel in an oil bath and heat and stir it under normal pressure, set the reaction temperature to 140 °C, and the reaction time to 2 h. After the reaction is completed, quickly cool the reaction solution in cold water to quench the reaction and generate a mixture containing the crude product of 3-acetamido-5-acetylfuran;

[0061] Step 4: Filter the mixture containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract it three times with a water-ethyl acetate (volume ratio 1:5) mixed solvent, then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize it in cold water to obtain 3-acetamido-5-acetylfuran ( 1 The \(^1H\) nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic resonance technology, the yield of 3-acetamido-5-acetylfuran is 56%.

[0062] Example 7

[0063] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0064] Step 1: Mix the hydrogen bond acceptor arginine, the alcohol hydrogen bond donor 1,3-butanediol, and the acid hydrogen bond donor malic acid in a molar ratio of 1:5:1.5, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural eutectic solvent. Then place it in a vacuum drying oven and dry at 50 °C for 24 h for later use;

[0065] Step 2: Weigh 1 g of D-acetylglucosamine and 20 g of the natural eutectic solvent in a reaction vessel, stir, and mix evenly;

[0066] Step 3: Place the reaction vessel in an oil bath and heat and stir at atmospheric pressure. Set the reaction temperature to 140 °C and the reaction time to 2 h. After the reaction is completed, quickly cool the reaction solution in cold water to quench the reaction, generating a mixed solution containing the crude product of 3-acetamido-5-acetylfuran;

[0067] Step 4: Filter the mixed solution containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract it three times with a water-ethyl acetate (volume ratio 1:5) mixed solvent, then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize it in cold water to obtain 3-acetamido-5-acetylfuran ( 1 The 1H nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic resonance technology, the yield of 3-acetamido-5-acetylfuran is 41%.

[0068] Example 8

[0069] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0070] Step 1: Mix the hydrogen bond acceptor arginine, the alcohol hydrogen bond donor 1,4-butanediol, and the acid hydrogen bond donor acetic acid in a molar ratio of 1:5:2, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural eutectic solvent. Then place it in a vacuum drying oven and dry at 50 °C for 24 h for later use;

[0071] Step 2: Weigh 1 g of D-acetylglucosamine and 20 g of the natural eutectic solvent in a reaction vessel, stir, and mix evenly;

[0072] Step 3: Place the reaction vessel in an oil bath and heat and stir at atmospheric pressure. Set the reaction temperature to 130 °C and the reaction time to 2 h. After the reaction is completed, quickly cool the reaction solution in cold water to quench the reaction, generating a mixed solution containing the crude product of 3-acetamido-5-acetylfuran;

[0073] Step 4: Filter the mixed solution containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract it three times with a mixed solvent of water-ethyl acetate (volume ratio 1:5), then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize it in cold water to obtain 3-acetamido-5-acetylfuran ( 1 The 1H nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic resonance technology, the yield of 3-acetamido-5-acetylfuran is 49%.

[0074] Example 9

[0075] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0076] Step 1: Mix the hydrogen bond acceptor arginine, the alcohol hydrogen bond donor ethylene glycol, and the acid hydrogen bond donor formic acid in a molar ratio of 1:5:1, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural eutectic solvent, and then place it in a vacuum drying oven and dry it at 50 °C for 24 h for standby;

[0077] Step 2: Weigh 1 g of D-acetamido glucose and 20 g of the natural eutectic solvent in a reaction vessel, stir, and mix evenly;

[0078] Step 3: Place the reaction vessel in an oil bath and heat and stir it under normal pressure, set the reaction temperature to 120 °C, and the reaction time to 1.5 h. After the reaction is completed, quickly cool the reaction solution in cold water to quench the reaction and generate a mixed solution containing the crude product of 3-acetamido-5-acetylfuran;

[0079] Step 4: Filter the mixed solution containing the crude product of 3-acetamido-5-acetylfuran to remove insoluble impurities, extract it three times with a mixed solvent of water-ethyl acetate (volume ratio 1:5), then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize it in cold water to obtain 3-acetamido-5-acetylfuran ( 1 The 1H nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic resonance technology, the yield of 3-acetamido-5-acetylfuran is 47%.

[0080] Example 10

[0081] A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, comprising the following steps:

[0082] Step 1: Mix the hydrogen bond acceptor arginine, the alcohol hydrogen bond donor glycerol, and the acid hydrogen bond donor citric acid in a molar ratio of 1:5:1, stir and heat at 80 °C for 0.5 h to form a colorless and transparent ternary natural eutectic solvent, and then place it in a vacuum drying oven and dry it at 50 °C for 24 h for standby;

[0083] Step 2: Weigh 1 g of D - acetamido - glucose and 20 g of natural eutectic solvent in a reaction vessel, stir, and mix evenly.

[0084] Step 3: Place the reaction vessel in an oil bath and heat - stir it under normal pressure. Set the reaction temperature at 110 °C and the reaction time at 1.5 h. After the reaction ends, quickly cool the reaction solution in cold water to quench the reaction, generating a mixed solution containing the crude product of 3 - acetamido - 5 - acetyl - furan.

[0085] Step 4: Filter the mixed solution containing the crude product of 3 - acetamido - 5 - acetyl - furan to remove insoluble impurities, extract it three times with a water - ethyl acetate (volume ratio 1:5) mixed solvent, then distill off the solvent under reduced pressure in a rotary evaporator, and crystallize it in cold water to obtain 3 - acetamido - 5 - acetyl - furan ( 1 The ¹H nuclear magnetic resonance spectrum is as Figure 1 shown). Analyzed by quantitative nuclear magnetic technology, the yield of 3 - acetamido - 5 - acetyl - furan is 39%.

[0086] The above shows and describes the main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above - mentioned exemplary embodiments, and without departing from the spirit or basic features of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non - restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention.

[0087] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran, characterized in that, It includes the following steps: Step 1: Stir D-glucosamine and a ternary natural eutectic solvent at room temperature until evenly mixed to obtain a mixed solution, where the ternary natural eutectic solvent includes a hydrogen bond acceptor, an alcohol hydrogen bond donor, and an acid hydrogen bond donor. The hydrogen bond acceptor is a natural component, proline or arginine. The alcohol hydrogen bond donor is any one of glycerol, ethylene glycol, 1,3-butanediol, and 1,4-butanediol. The acid hydrogen bond donor is one of lactic acid, formic acid, acetic acid, malic acid, and citric acid. The molar ratio of the hydrogen bond acceptor, the alcohol hydrogen bond donor, and the acid hydrogen bond donor is 1:5:0.5 - 2; Step 2: Heat and stir the mixed solution to generate a mixed solution containing the crude product of 3-acetamido-5-acetylfuran. The heating temperature is 100°C - 140°C, the time is 0.5 h - 2 h, and the pressure is atmospheric pressure; Step 3: After the mixed solution containing the crude product of 3-acetamido-5-acetylfuran is filtered, extracted, and subjected to vacuum distillation, it is crystallized in cold water to obtain the product 3-acetamido-5-acetylfuran.

2. The method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran according to claim 1, characterized in that, The D-glucosamine in Step 1 is derived from the natural nitrogen-containing biomass chitin.

3. A method for preparing a nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran according to claim 1, characterized in that, The preparation method of the ternary natural eutectic solvent in Step 1 is as follows: Stir and heat the hydrogen bond acceptor, the alcohol hydrogen bond donor, and the acid hydrogen bond donor at 80°C to form a colorless transparent liquid, and then dry it at 50°C to obtain the ternary natural eutectic solvent.

4. A method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran according to claim 1, wherein, The mass ratio of D-glucosamine to the ternary natural eutectic solvent in Step 1 is 1:

20.

5. The method for preparing the nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran according to claim 1, characterized in that, In Step 3, extraction is carried out using a water-ethyl acetate mixed solvent, and the volume ratio of water to ethyl acetate is 1:

5.

6. A method for preparing a nitrogen-containing heterocyclic compound 3-acetamido-5-acetylfuran according to claim 1, characterized in that, The temperature of vacuum distillation in Step 3 is 60°C.

Images