A process for the preparation of N-(2,2-dimethoxyethyl)-1H-imidazole-1-carboxamide (183660-46-0)

Abstract

The present application relates to the technical field of chemical material production, and particularly relates to a preparation method of N-(2,2-dimethoxyethyl)-1H-imidazole-1-formamide (183660-46-0); clean dichloromethane is added into a clean reaction kettle; the temperature of the reaction kettle is reduced to -5-5 DEG C, N,N'-carbonyldiimidazole is added; aminoacetaldehyde dimethyl acetal is added dropwise, and reaction is carried out for 2h; the temperature of the reaction kettle is increased, and stirring is continuously carried out at 18-25 DEG C for 12-16h, so that white suspension is obtained; normal heptane is slowly added dropwise at 18-25 DEG C, the dropwise adding time is 1-2h, stirring is continuously carried out at 18-25 DEG C for 2h, filtration is carried out under the protection of nitrogen, and the filter cake is washed once with a mixed solution of dichloromethane and normal heptane; dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazole-1-formamide are added, stirring is carried out at 20-25 DEG C for 30min, normal heptane is slowly added and stirred for 1h, the filter cake is collected, and drying is carried out; the fine operation of the product processing process is realized, the generation of by-products is effectively reduced, impurity wrapping and raw material residue are avoided, and the purity of the target product is improved.

Description

Technical Field

[0001] This invention relates to the field of chemical material production technology, and in particular to a method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0). Background Technology

[0002] N-(2,2-Dimethoxyethyl)-1H-imidazolium-1-carboxamide is an important nitrogen-containing heterocyclic organic intermediate. Its molecular structure contains both an imidazolium ring and an amide group, which are active functional groups. It has wide applications in the fields of pharmaceuticals, fine chemicals, and new material synthesis. It can be used as a key intermediate in the synthesis of antifungal drugs, antiviral drugs, and functional polymer materials.

[0003] Currently, the existing technologies for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) mostly employ a synthetic route that directly reacts imidazolium derivatives with amidating reagents in organic solvents. This type of method is the conventional approach for preparing such amide compounds in the industry. Generally, a single halogenated hydrocarbon or ether is used as the reaction solvent, and the reaction and combination of raw materials are achieved through simple temperature control and stirring. Some processes will use a single alkane solvent such as n-hexane or petroleum ether for simple crystallization treatment after the reaction, and then directly dry to obtain the finished product.

[0004] In the existing methods, the process parameters of N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide are poorly controlled, and the reaction and post-processing lack precise control, resulting in low product purity and poor quality stability. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide (183660-46-0), aiming to solve the technical problems of low product purity and poor quality stability caused by the extensive control of process parameters and lack of precise control of reaction and post-processing in existing methods for N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide.

[0006] To achieve the above objectives, the present invention employs a method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0), comprising the following steps: Under nitrogen protection at room temperature, add 5 times the weight of dichloromethane to a clean reactor and start stirring; Lower the temperature of the reactor to -5~5℃, and add 1 weight of N,N'-carbonyldiimidazole; Add 0.62 times its weight of aminoacetaldehyde dimethyl acetal dropwise over 1-2 hours. After the addition is complete, allow the reaction to proceed for 2 hours. The temperature of the reactor was raised to 15-23°C, and stirring was continued at 18-25°C for 12-16 hours to obtain a white suspension. At 18~25℃, 5 times the weight of n-heptane was slowly added dropwise over 1~2 hours. After the addition was complete, the mixture was stirred at 18~25℃ for another 2 hours. The mixture was then filtered under nitrogen protection. The filter cake was washed once with a mixed solution of dichloromethane and n-heptane to obtain crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide. Add 2 times the weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide, and stir at 20~25℃ for 30 min. Then slowly add 2 times the weight of n-heptane and continue stirring at 20~25℃ for 1 h. Filter under nitrogen protection, collect the filter cake, and dry to obtain high-purity N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product.

[0007] In the step of adding 5 times its weight of dichloromethane to a clean reactor under nitrogen protection at room temperature and starting the stirring: The room temperature range is 20~30℃.

[0008] In the step of lowering the reactor temperature to -5~5℃ and adding 1 times the weight of N,N'-carbonyldiimidazole: The molar equivalent of N,N'-carbonyldiimidazole is 1.0, and the temperature inside the reactor is kept stable at -5~5℃ without fluctuation during the feeding process.

[0009] In the step of adding 0.62 times its weight of aminoacetaldehyde dimethyl acetal over 1-2 hours, followed by a 2-hour reaction period after the addition is complete: The molar equivalent of aminoacetaldehyde dimethyl acetal is 0.95. The addition process adopts a constant rate dropping method, and the temperature of the reaction system is maintained at -5~5℃ throughout the process.

[0010] In the step of raising the temperature of the reaction vessel to 15~23℃ and continuing stirring at 18~25℃ for 12~16 hours to obtain a white suspension: The heating process adopts a gradient heating method, with the heating rate controlled at 2~5℃ / h and the stirring speed maintained at 200~500r / min.

[0011] In the step of slowly adding 5 times its weight of n-heptane dropwise at 18-25℃ for 1-2 hours, and then stirring at 18-25℃ for another 2 hours after the addition is complete, filtering under nitrogen protection, and washing the filter cake once with a mixed solution of dichloromethane and n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide: During the dropwise addition of n-heptane, the mixture is continuously stirred at a speed of 200-500 r / min.

[0012] In the step of slowly adding 5 times its weight of n-heptane dropwise at 18-25℃ for 1-2 hours, and then stirring at 18-25℃ for another 2 hours after the addition is complete, filtering under nitrogen protection, and washing the filter cake once with a mixed solution of dichloromethane and n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide: In a mixed solution of dichloromethane and n-heptane, the amount of dichloromethane is 0.35 times the weight of N,N'-carbonyldiimidazole, and the amount of n-heptane is 1 times the weight of N,N'-carbonyldiimidazole. The washing method is rinsing.

[0013] In the step of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide, stirring at 20-25°C for 30 minutes, then slowly adding 2 times its weight of n-heptane, continuing stirring at 20-25°C for 1 hour, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide product: During the stirring process, observe the state of the solution. Stop stirring when the crude product has completely dissolved and formed a clear solution.

[0014] In the step of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide, stirring at 20-25°C for 30 minutes, then slowly adding 2 times its weight of n-heptane, continuing stirring at 20-25°C for 1 hour, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide product: Heptane was added dropwise, and during the addition process, crystals were observed to gradually precipitate in the system.

[0015] In the step of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide, stirring at 20-25°C for 30 minutes, then slowly adding 2 times its weight of n-heptane, continuing stirring at 20-25°C for 1 hour, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide product: The drying process uses vacuum drying, with a drying temperature of 40~60℃ and a vacuum degree of -0.08~-0.1MPa, until the filter cake reaches a constant weight.

[0016] The present invention discloses a method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0), comprising the following steps: First, under nitrogen protection at room temperature, 5 times the weight of dichloromethane is added to a clean reaction vessel, and stirring is started; then, the temperature of the reaction vessel is lowered to -5~5℃, and 1 times the weight of N,N'-carbonyldiimidazole is added; 0.62 times the weight of aminoacetaldehyde dimethyl acetal is added dropwise over 1~2 hours, and after the addition is complete, the reaction is allowed to proceed for 2 hours; then, the temperature of the reaction vessel is raised to 15~23℃, and stirring is continued at 18~25℃ for 12~16 hours to obtain a white suspension; then, 5 times the weight of n-heptane is slowly added dropwise at 18~25℃ over 1~2 hours, and after the addition is complete, stirring is continued at 18~25℃. The mixture was stirred for 2 hours, filtered under nitrogen protection, and the filter cake was washed once with a mixed solution of dichloromethane and n-heptane to obtain crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide. Then, twice the weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide were added, and the mixture was stirred at 20-25°C for 30 minutes. Then, twice the weight of n-heptane was slowly added, and the mixture was stirred at 20-25°C for 1 hour. The mixture was filtered under nitrogen protection, the filter cake was collected, and dried to obtain high-purity N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide. This method achieved refined operation of the product processing, effectively reducing byproduct generation, avoiding impurity encapsulation and raw material residue, and improving the purity of the target product. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of the preparation method of N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) according to the present invention. Detailed Implementation

[0019] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0020] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0021] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0022] Please see Figure 1 , Figure 1 This is a flowchart illustrating the steps of a method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) according to the present invention. The present invention provides a method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0), comprising the following steps: S100: Under nitrogen protection at room temperature, add 5 times the weight of dichloromethane to a clean reactor and start stirring; S200: Lower the temperature of the reactor to -5~5℃ and add 1 weight of N,N'-carbonyldiimidazole; S300: Add 0.62 times the weight of aminoacetaldehyde dimethyl acetal dropwise over 1-2 hours. After the addition is complete, allow the reaction to proceed for 2 hours. S400: Heat the reactor to 15~23℃, and continue stirring at 18~25℃ for 12~16h to obtain a white suspension; S500: At 18~25℃, slowly add 5 times the weight of n-heptane dropwise over 1~2 hours. After the addition is complete, continue stirring at 18~25℃ for 2 hours. Filter under nitrogen protection and wash the filter cake once with a mixed solution of dichloromethane and n-heptane to obtain crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide. S600: Add 2 times the weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide, control the temperature at 20~25℃ and stir for 30 min, then slowly add 2 times the weight of n-heptane, continue stirring at 20~25℃ for 1 h, filter under nitrogen protection, collect the filter cake, dry it to obtain high-purity N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product.

[0023] Furthermore, under nitrogen protection at room temperature, five times the weight of dichloromethane is added to a clean reactor, and stirring is started: The room temperature range is 20~30℃.

[0024] Furthermore, in the step of lowering the reactor temperature to -5 to 5°C and adding 1 times the weight of N,N'-carbonyldiimidazole: The molar equivalent of N,N'-carbonyldiimidazole is 1.0, and the temperature inside the reactor is kept stable at -5~5℃ without fluctuation during the feeding process.

[0025] Furthermore, in the step of adding 0.62 times its weight of aminoacetaldehyde dimethyl acetal over 1-2 hours, followed by a 2-hour reaction after the addition is complete: The molar equivalent of aminoacetaldehyde dimethyl acetal is 0.95. The addition process adopts a constant rate dropping method, and the temperature of the reaction system is maintained at -5~5℃ throughout the process.

[0026] Furthermore, in the step of raising the temperature of the reaction vessel to 15~23℃ and continuing stirring at 18~25℃ for 12~16 hours to obtain a white suspension: The heating process adopts a gradient heating method, with the heating rate controlled at 2~5℃ / h and the stirring speed maintained at 200~500r / min.

[0027] Further, at 18-25°C, 5 times its weight of n-heptane was slowly added dropwise over 1-2 hours. After the addition was complete, stirring was continued at 18-25°C for 2 hours. The mixture was then filtered under nitrogen protection. The filter cake was washed once with a mixed solution of dichloromethane and n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide. During the dropwise addition of n-heptane, the mixture is continuously stirred at a speed of 200-500 r / min.

[0028] Further, at 18-25°C, 5 times its weight of n-heptane was slowly added dropwise over 1-2 hours. After the addition was complete, stirring was continued at 18-25°C for 2 hours. The mixture was then filtered under nitrogen protection. The filter cake was washed once with a mixed solution of dichloromethane and n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide. In a mixed solution of dichloromethane and n-heptane, the amount of dichloromethane is 0.35 times the weight of N,N'-carbonyldiimidazole, and the amount of n-heptane is 1 times the weight of N,N'-carbonyldiimidazole. The washing method is rinsing.

[0029] Further, in the steps of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide, stirring at 20~25℃ for 30 min, then slowly adding 2 times its weight of n-heptane, continuing stirring at 20~25℃ for 1 h, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide product: During the stirring process, observe the state of the solution. Stop stirring when the crude product has completely dissolved and formed a clear solution.

[0030] Further, in the steps of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide, stirring at 20~25℃ for 30 min, then slowly adding 2 times its weight of n-heptane, continuing stirring at 20~25℃ for 1 h, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide product: Heptane was added dropwise, and during the addition process, crystals were observed to gradually precipitate in the system.

[0031] Further, in the steps of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide, stirring at 20~25℃ for 30 min, then slowly adding 2 times its weight of n-heptane, continuing stirring at 20~25℃ for 1 h, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide product: The drying process uses vacuum drying, with a drying temperature of 40~60℃ and a vacuum degree of -0.08~-0.1MPa, until the filter cake reaches a constant weight.

[0032] In this embodiment, under nitrogen protection at room temperature (20~30℃), 5 times the weight of dichloromethane was added to a clean reactor, and stirring was started; the reactor temperature was lowered to -5~5℃, and 1 times the weight of N,N'-carbonyldiimidazole was added, wherein the molar equivalent of N,N'-carbonyldiimidazole was 1.0; 0.62 times the weight of aminoacetaldehyde dimethyl acetal was added dropwise, wherein the molar equivalent of aminoacetaldehyde dimethyl acetal was 0.95. The dropwise addition was carried out at a constant rate, and the reaction system temperature was maintained at -5~5℃ throughout the process. After 1-2 hours of addition, allow the reaction to proceed for 2 hours. Then, raise the reactor temperature to 15-23°C and continue stirring at 18-25°C for 12-16 hours to obtain a white suspension. The heating process uses a gradient heating method, with a heating rate controlled at 2-5°C / h, and the stirring speed maintained at 200-500 rpm. At 18-25°C, slowly add 5 times its weight of n-heptane dropwise over 1-2 hours. After the addition is complete, continue stirring at 18-25°C (200-500 rpm) for 2 hours under nitrogen protection. The filter cake was washed once with a mixed solution of 0.35 times its weight of dichloromethane and 1 times its weight of n-heptane to obtain crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide. During stirring, the solution state was observed, and stirring was stopped when the crude product was completely dissolved and a clear solution was formed. Then, 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide were added, and the mixture was stirred at 20-25°C for 30 minutes. Finally, 2 times its weight of n-heptane was slowly added. (Added dropwise), continue stirring at 20~25℃ for 1 hour, filter under nitrogen protection, collect the filter cake, and dry (using vacuum drying method, drying temperature of 40~60℃, vacuum degree of -0.08~-0.1MPa, drying until the filter cake has a constant weight), to obtain a high-purity N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide product; through the above method, the product processing process is refined, effectively reducing the generation of by-products, avoiding impurity encapsulation and raw material residue, and improving the purity of the target product.

[0033] Example 1: Preparation of crude product: Under nitrogen protection at 25℃, 50 kg of dichloromethane was added to the reactor. After stirring, the temperature was lowered to 0℃, and 10 kg of N,N'-carbonyldiimidazole was added. 6.2 kg of aminoacetaldehyde dimethyl acetal was slowly added dropwise at 0℃ for 1.5 h. After the addition was complete, the reaction was carried out at 0℃ for 2 h, and then the temperature was raised to 20℃ and stirred at 20℃ for 14 h to obtain a white suspension. 50 kg of n-heptane was slowly added dropwise at 20℃ for 1.5 h, and stirring was continued for 2 h after the addition was complete. The mixture was filtered under nitrogen protection, and the filter cake was washed once with a mixed solution of 3.5 kg of dichloromethane and 10 kg of n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide.

[0034] Refining: Take the above crude product HSDTM1, add 2 times the weight of dichloromethane, stir at 22°C for 30 min to dissolve the crude product, slowly add 2 times the weight of n-heptane, and continue stirring at 22°C for 1 h; filter under nitrogen protection, collect the filter cake and dry it to obtain N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product.

[0035] Example 2: Preparation of crude product: Under nitrogen protection at 20℃, 500 kg of dichloromethane was added to the reactor. After stirring, the temperature was lowered to -5℃, and 100 kg of N,N'-carbonyldiimidazole was added. 62 kg of aminoacetaldehyde dimethyl acetal was slowly added dropwise at -5℃ for 2 hours. After the addition was complete, the reaction was carried out at -5℃ for 2 hours, then the temperature was raised to 15℃ and stirred at 18℃ for 16 hours to obtain a white suspension. 500 kg of n-heptane was slowly added dropwise at 18℃ for 2 hours. After the addition was complete, stirring was continued for 2 hours. The mixture was filtered under nitrogen protection, and the filter cake was washed once with a mixed solution of 35 kg of dichloromethane and 100 kg of n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide. Purification: Take the above crude product HSDTM1, add 2 times the weight of dichloromethane, stir at 20°C for 30 min to dissolve the crude product, slowly add 2 times the weight of n-heptane, and continue stirring at 20°C for 1 h; filter under nitrogen protection, collect the filter cake and dry it to obtain N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product.

[0036] Example 3: Preparation of crude product: Under nitrogen protection at 30℃, 25 kg of dichloromethane was added to the reactor. After stirring, the temperature was lowered to 5℃, and 5 kg of N,N'-carbonyldiimidazole was added. 3.1 kg of aminoacetaldehyde dimethyl acetal was slowly added dropwise at 5℃ for 1 hour. After the addition was complete, the reaction was carried out at 5℃ for 2 hours, then the temperature was raised to 23℃ and stirred at 25℃ for 12 hours to obtain a white suspension. 25 kg of n-heptane was slowly added dropwise at 25℃ for 1 hour, and stirring was continued for 2 hours after the addition was complete. The mixture was filtered under nitrogen protection, and the filter cake was washed once with a mixed solution of 1.75 kg of dichloromethane and 5 kg of n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide. Purification: Take the above crude product HSDTM1, add 2 times the weight of dichloromethane, stir at 25°C for 30 min to dissolve the crude product, slowly add 2 times the weight of n-heptane, and continue stirring at 25°C for 1 h; filter under nitrogen protection, collect the filter cake and dry it to obtain N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product.

[0037] In the above embodiments, the obtained finished products were tested and found to have a purity of over 99% and a yield of over 85%.

[0038] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0039] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0), characterized in that, The steps include the following: Under nitrogen protection at room temperature, add 5 times the weight of dichloromethane to a clean reactor and start stirring; Lower the temperature of the reactor to -5~5℃, and add 1 weight of N,N'-carbonyldiimidazole; Add 0.62 times its weight of aminoacetaldehyde dimethyl acetal dropwise over 1-2 hours. After the addition is complete, allow the reaction to proceed for 2 hours. The temperature of the reactor was raised to 15-23°C, and stirring was continued at 18-25°C for 12-16 hours to obtain a white suspension. At 18~25℃, 5 times the weight of n-heptane was slowly added dropwise over 1~2 hours. After the addition was complete, the mixture was stirred at 18~25℃ for another 2 hours. The mixture was then filtered under nitrogen protection. The filter cake was washed once with a mixed solution of dichloromethane and n-heptane to obtain crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide. Add 2 times the weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide, and stir at 20~25℃ for 30 min. Then slowly add 2 times the weight of n-heptane and continue stirring at 20~25℃ for 1 h. Filter under nitrogen protection, collect the filter cake, and dry to obtain high-purity N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product.

2. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 1, characterized in that, Under nitrogen protection at room temperature, add 5 times the weight of dichloromethane to a clean reactor and start stirring: The room temperature range is 20~30℃.

3. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 1, characterized in that, In the step of lowering the reactor temperature to -5~5℃ and adding 1 times the weight of N,N'-carbonyldiimidazole: The molar equivalent of N,N'-carbonyldiimidazole is 1.0, and the temperature inside the reactor is kept stable at -5~5℃ without fluctuation during the feeding process.

4. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 1, characterized in that, In the step of adding 0.62 times its weight of aminoacetaldehyde dimethyl acetal dropwise over 1-2 hours, followed by a 2-hour reaction period after the addition is complete: The molar equivalent of aminoacetaldehyde dimethyl acetal is 0.

95. The addition process adopts a constant rate dropping method, and the temperature of the reaction system is maintained at -5~5℃ throughout the process.

5. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 1, characterized in that, In the step of raising the temperature of the reaction vessel to 15~23℃ and continuing stirring at 18~25℃ for 12~16 hours to obtain a white suspension: The heating process adopts a gradient heating method, with the heating rate controlled at 2~5℃ / h and the stirring speed maintained at 200~500r / min.

6. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 1, characterized in that, At 18-25℃, 5 times its weight of n-heptane was slowly added dropwise over 1-2 hours. After the addition was complete, stirring was continued at 18-25℃ for 2 hours. The mixture was then filtered under nitrogen protection. The filter cake was washed once with a mixed solution of dichloromethane and n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide. During the dropwise addition of n-heptane, the mixture is continuously stirred at a speed of 200-500 r / min.

7. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 6, characterized in that, At 18-25℃, 5 times its weight of n-heptane was slowly added dropwise over 1-2 hours. After the addition was complete, stirring was continued at 18-25℃ for 2 hours. The mixture was then filtered under nitrogen protection. The filter cake was washed once with a mixed solution of dichloromethane and n-heptane to obtain the crude product N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide. In a mixed solution of dichloromethane and n-heptane, the amount of dichloromethane is 0.35 times the weight of N,N'-carbonyldiimidazole, and the amount of n-heptane is 1 times the weight of N,N'-carbonyldiimidazole. The washing method is rinsing.

8. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 1, characterized in that, In the step of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide, stirring at 20~25℃ for 30 min, then slowly adding 2 times its weight of n-heptane, and continuing stirring at 20~25℃ for 1 h, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product: During the stirring process, observe the state of the solution. Stop stirring when the crude product has completely dissolved and formed a clear solution.

9. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 8, characterized in that, In the step of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide, stirring at 20~25℃ for 30 min, then slowly adding 2 times its weight of n-heptane, and continuing stirring at 20~25℃ for 1 h, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product: Heptane was added dropwise, and during the addition process, crystals were observed to gradually precipitate in the system.

10. The method for preparing N-(2,2-dimethoxyethyl)-1H-imidazolium-1-carboxamide (183660-46-0) as described in claim 9, characterized in that, In the step of adding 2 times its weight of dichloromethane and crude N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide, stirring at 20~25℃ for 30 min, then slowly adding 2 times its weight of n-heptane, and continuing stirring at 20~25℃ for 1 h, filtering under nitrogen protection, collecting the filter cake, drying, and obtaining high-purity N-(2,2-dimethoxyethyl)-1H-imidazol-1-carboxamide product: The drying process uses vacuum drying, with a drying temperature of 40~60℃ and a vacuum degree of -0.08~-0.1MPa, until the filter cake reaches a constant weight.

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