The invention relates to N, Napos; synthesis method of-[(4-diazo-4H-pyrazole-3, 5-diyl) bis (1, 2, 5-oxadiazole-4, 3-diyl)] dinitramide
N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide was prepared by [4+1] cycloaddition reaction and hydrolysis-nitration reaction, which solved the problems of low efficiency and single bridging structure of traditional synthesis methods, achieved a balance between high energy density and low sensitivity, and improved the thermal stability and safety of the material.
Patent Information
- Application Number
- CN202510940809.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-09
- Publication Date
- 2025-11-21
AI Technical Summary
Existing methods for synthesizing energetic materials are inefficient and have poor atom economy, making it difficult to achieve a balance between high energy density and low sensitivity. Traditional cycloaddition strategies have limited applications and offer only a single type of bridging structure.
N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide was prepared by combining a [4+1] cycloaddition reaction with hydrolysis and nitration, using the diazopyrazole ring as a bridging structure.
An energetic compound with high thermal stability, low sensitivity and high detonation performance was achieved, with a thermal decomposition temperature increased by 10.8℃ and a significant improvement in impact sensitivity and friction sensitivity.
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Figure CN120987933A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of energetic materials technology, specifically relating to a method for synthesizing N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide, an energetic compound with high thermal stability and low sensitivity, and its application in high energy density materials. Background Technology
[0002] Energetic materials, as core foundational materials in defense technology and civilian blasting, have always had their performance optimization revolving around the contradiction between "high energy density" and "low sensitivity." High energy density usually relies on the dense distribution of high-energy groups (such as nitro and nitramine groups) or the construction of strained ring structures (such as octagonal rings and cage-like rings) in the molecule. However, such structures are often accompanied by problems such as increased intramolecular stress, decreased thermal stability, and increased mechanical sensitivity (impact / friction sensitivity), leading to significant safety risks in practical applications.
[0003] Traditional synthetic methods often employ reactions such as oxidation, reduction, electrophilic substitution, and nucleophilic substitution for the synthesis of energetic materials. This results in low efficiency and poor atom economy in the synthesis of energetic materials. Developing a synthetic method for energetic compounds based on novel cycloaddition reaction strategies, which holds promise for achieving precise construction of the molecular framework while balancing energy density and stability, is a pressing technical challenge in the field of energetic materials.
[0004] Introducing bridging structures between two energetic units via cycloaddition strategies has been proven to significantly affect material properties. For example, Shreve et al., in their paper "1,3,4-Oxadiazole Bridges: A Strategy to Improve Energetics at the Molecular Level" (Angew. Chem. Int. Ed. 2021, 60, 5497-5504), used 1,3,4-oxadiazole as a bridging structure. The steric hindrance effect of the bridging unit reduced mechanical sensitivity, demonstrating the unique advantage of bridging strategies in balancing energy and stability. However, the application of cycloaddition strategies in the synthesis of energetic materials is currently limited to a few classic reactions, and the types of bridging structures are limited. Therefore, developing novel cycloaddition reaction systems and functional bridging modules holds promise for overcoming the efficiency bottleneck of traditional synthetic methods and providing a new pathway for designing next-generation energetic materials with "high energy and low sensitivity." Summary of the Invention
[0005] The main objective of this invention is to overcome the shortcomings and defects in the prior art and provide a method for preparing N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide, which solves the problem that existing cycloaddition reactions are rarely used in the field of energetic materials. This invention provides an energetic compound with high thermal stability, low sensitivity and high detonation performance by using the diazopyrazole ring as a bridging structure.
[0006] To achieve the above-mentioned technical objectives, the present invention employs the following technical solution:
[0007] A method for preparing N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide, comprising:
[0008] Step 1: Phenethyl isonitrile and 4,4′-(1,2,4,5-tetraazine-3,6-diyl)bis(1,2,5-oxadiazol-3-amine) undergo a [4+1] cycloaddition reaction in an organic solvent to give a diazapyridine intermediate;
[0009] Step 2: Hydrolyze the diazapyridine intermediate under concentrated hydrochloric acid to prepare 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine);
[0010] Step 3: Nitrate 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) under nitric acid conditions to obtain N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide.
[0011] Optionally, in step 1, the organic solvent is dimethyl sulfoxide.
[0012] Optionally, in step 2, the diazapyridine intermediate is dissolved in methanol and then hydrolyzed with hydrochloric acid; the hydrochloric acid is concentrated hydrochloric acid.
[0013] Optionally, in step 3, the nitric acid is concentrated nitric acid.
[0014] Optionally, the molar ratio between 4,4′-(1,2,4,5-tetraazine-3,6-diyl)bis(1,2,5-oxadiazol-3-amine) and phenethyl isonitrile is 1:(1.5-2).
[0015] Optionally, the molar ratio of the diazapyridine intermediate to hydrochloric acid is 1:(8-12).
[0016] Optionally, the molar ratio of 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) to nitric acid is 1:(1-1.2).
[0017] Optionally, step 1 specifically includes:
[0018] Phenethyl isonitrile was added to a dimethyl sulfoxide solution of 4,4′-(1,2,4,5-tetraazine-3,6-diyl)bis(1,2,5-oxadiazol-3-amine), and the mixture was stirred at 20–30 °C for 20–24 hours. The solution color changed from red to colorless. Water was added to the reaction system, the precipitate was collected and dried to obtain the diazapyridine intermediate.
[0019] Optionally, step 2 specifically includes:
[0020] The diazapyridine intermediate was dissolved in 10–30 mL of methanol, heated to 50–70 °C, and 4–5 mL of concentrated hydrochloric acid was added with stirring. The reaction was carried out for 10–15 hours. After the reaction was completed, the mixture was cooled to room temperature, the precipitate was collected, and the mother liquor was concentrated to obtain the crude product. The crude product was then recrystallized from boiling water to obtain 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine).
[0021] Optionally, step 3 specifically includes:
[0022] 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) was slowly added dropwise to 1–3 mL of concentrated nitric acid and reacted at 0–5 °C for 20–40 minutes. Then the temperature was raised to room temperature and stirring was continued for 1.5–2 hours. After the reaction was completed, the clear solution was poured into ice, and a precipitate was formed. The precipitate was collected and recrystallized from distilled water to obtain the target compound as a white solid.
[0023] Compared with the prior art, the advantages of the present invention are:
[0024] This invention utilizes tetrazine and phenylethyl isonitrile as raw materials, and through a previously unreported [4+1] cycloaddition reaction followed by hydrolysis and nitration, to obtain N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide via a three-step reaction. The energetic material N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide provided by this invention exhibits excellent high thermal stability, low sensitivity, and high detonation performance. Compared with RDX, its thermal decomposition temperature is increased by 10.8℃, its impact sensitivity is increased by 32.6J, and its friction sensitivity is increased by 240N. Attached Figure Description
[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:
[0026] Figure 1 The hydrogen nuclear magnetic resonance spectrum of the product obtained in Example 1 of this invention;
[0027] Figure 2 The nuclear magnetic resonance carbon spectrum of the product obtained in Example 1 of this invention;
[0028] Figure 3 The X-ray single-crystal diffraction pattern of the product obtained in Example 1 of this invention;
[0029] Figure 4 The image shows the DSC spectrum of the product obtained in Example 1 of this invention. Detailed Implementation
[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0031] The present invention provides a method for preparing N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide, which is achieved through the following steps:
[0032] Step 1: Add phenethyl isonitrile to 1-3 mL of 4,4′-(1,2,4,5-tetrazine-3,6-diyl)bis(1,2,5-oxadiazol-3-amine) in dimethyl sulfoxide, stir and react at 20-30°C for 20-24 hours. The solution color changes from red to colorless. Add water to the reaction system, collect the precipitate and dry it to obtain the diazapyridine intermediate. The molar ratio between the starting material 4,4′-(1,2,4,5-tetrazine-3,6-diyl)bis(1,2,5-oxadiazol-3-amine) and phenethyl isonitrile is 1:(1.5-2).
[0033] Step 2: Dissolve the diazaporide intermediate obtained in Step 1 in 10-30 mL of methanol, heat to 50-70 °C and add 4-5 mL of concentrated hydrochloric acid while stirring. React for 10-15 hours. After the reaction is complete, cool to room temperature, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine), wherein the molar ratio of diazaporide intermediate to hydrochloric acid is 1:(8-12).
[0034] Step 3: Slowly add the 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) obtained in Step 2 to 1–3 mL of nitric acid. React at 0–5 °C for 20–40 minutes, then raise the temperature to room temperature and continue stirring for 1.5–2 hours. After the reaction is complete, pour the clear solution into ice. A precipitate will form. Collect the precipitate and recrystallize it with distilled water to obtain a white solid target compound, wherein the molar ratio of 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) to nitric acid is 1:(1–1.2).
[0035] The present invention provides a method for preparing N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide, the reaction structure of which is as follows:
[0036]
[0037] In the reaction structural formula: acid 1 is concentrated hydrochloric acid, and acid 2 is concentrated nitric acid.
[0038] Note: 4,4′-(1,2,4,5-tetraazine-3,6-diyl)bis(1,2,5-oxadiazole-3-amine) is replaced by compound 1; diazapyridine intermediates are replaced by compound 2; 4,4′-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) is replaced by compound 3; N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide is replaced by compound 4.
[0039] The preparation method of compound 4 is carried out through the following steps:
[0040] Example 1
[0041] Step 1: Dissolve 100 mg of compound 1 in 2 mL of dimethyl sulfoxide solution, and add 100 mg of phenethyl isonitrile while stirring at 20 °C for 24 hours. When the reaction color changes from red to colorless, add 10 mL of water to the reaction system, collect the precipitate, and dry it to obtain 129 mg of white solid target compound 2, with a yield of 93%.
[0042] Step 2: Dissolve 129 mg of compound 2 obtained in step 1 in 10 mL of methanol, heat to 60 °C, add 3 mL of concentrated hydrochloric acid while stirring, react for 12 hours, cool to room temperature after the reaction is completed, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 43 mg of white powder containing solid compound 3, with a yield of 47%.
[0043] Step 3: 43 mg of compound 3 obtained in Step 2 was slowly added dropwise to 1 mL of nitric acid, and the reaction was carried out at 0 °C for 30 minutes. Then, the temperature was raised to room temperature and stirring was continued for 2 hours. After the reaction was completed, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 45 mg of white solid target compound 4, with a yield of 74%.
[0044] Figure 1 The hydrogen nuclear magnetic resonance spectrum of the product obtained in Example 1; Figure 2 The carbon NMR spectrum of the product obtained in Example 1; Figure 3 The X-ray single-crystal diffraction pattern of the product obtained in Example 1; Figure 4 The image shows the DSC spectrum of the product obtained in Example 1.
[0045] The spectral detection results and analysis are as follows (see details). Figure 1-4 ):
[0046] The product obtained in Example 1 was subjected to nuclear magnetic resonance (NMR) detection, and the detection data are as follows:
[0047] 1 H NMR (400MHz, DMSO) δ13.70(s,1H),6.39(s,4H),4.96(s,2H);
[0048] 13 C NMR (101MHz, DMSO) δ154.87,154.81,140.74,139.34,130.94,128.55,114.26;
[0049] HRMS(ESI):m / z calcd for C7H7N9O2 + H + :250.0795[M + H] + :found:250.0795.
[0050] Table 1 Physical properties and detonation performance
[0051]
[0052] The test data shows that the compound N,N′-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide prepared by this method has stable H atom peak positions in different chemical environments, no impurity peaks, high purity, and good separation.
[0053] Example 2
[0054] Step 1: Dissolve 200 mg of compound 1 in 4 mL of dimethyl sulfoxide solution, and add 200 mg of phenethyl isonitrile while stirring at 20 °C for 24 hours. When the reaction color changes from red to colorless, add 20 mL of water to the reaction system, collect the precipitate, and dry it to obtain 249 mg of white solid target compound 2, with a yield of 90%.
[0055] Step 2: Dissolve 215 mg of compound 2 obtained in step 1 in 20 mL of methanol, heat to 60 °C, add 5 mL of concentrated hydrochloric acid while stirring, react for 12 hours, cool to room temperature after the reaction is completed, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 71 mg of white powder containing solid compound 3, with a yield of 46%.
[0056] Step 3: 71 mg of compound 3 obtained in Step 2 was slowly added dropwise to 2 mL of nitric acid, and the reaction was carried out at 0 °C for 30 minutes. Then, the temperature was raised to room temperature and stirring was continued for 2 hours. After the reaction was completed, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 68 mg of white solid target compound 4, with a yield of 69%.
[0057] Example 3
[0058] Step 1: Dissolve 200 mg of compound 1 in 5 mL of dimethyl sulfoxide solution, and add 200 mg of phenethyl isonitrile while stirring at 10 °C for 22 hours. When the reaction color changes from red to colorless, add 20 mL of water to the reaction system, collect the precipitate, and dry it to obtain 230 mg of white solid target compound 2, with a yield of 83%.
[0059] Step 2: Dissolve 215 mg of compound 2 obtained in step 1 in 30 mL of methanol, heat to 70 °C, add 5 mL of concentrated hydrochloric acid while stirring, react for 12 hours, cool to room temperature after the reaction is complete, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 69 mg of white powder containing solid compound 3, with a yield of 45%.
[0060] Step 3: 50 mg of compound 3 obtained in Step 2 was slowly added dropwise to 1 mL of nitric acid, and the reaction was carried out at 0 °C for 20 minutes. Then, the temperature was raised to room temperature and stirring was continued for 2 hours. After the reaction was completed, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 40 mg of white solid target compound 4, with a yield of 57%.
[0061] Example 4
[0062] Step 1: Dissolve 200 mg of compound 1 in 5 mL of dimethyl sulfoxide solution, and add 200 mg of phenethyl isonitrile while stirring at 30 °C for 20 hours. When the reaction color changes from red to colorless, add 20 mL of water to the reaction system, collect the precipitate, and dry it to obtain 254 mg of white solid target compound 2, with a yield of 90%.
[0063] Step 2: Dissolve 215 mg of compound 2 obtained in step 1 in 25 mL of methanol, heat to 65 °C, add 5 mL of concentrated hydrochloric acid while stirring, react for 12 hours, cool to room temperature after the reaction is complete, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 72 mg of white powder containing solid compound 3, with a yield of 47%.
[0064] Step 3: 50 mg of compound 3 obtained in Step 2 was slowly added dropwise to 2 mL of nitric acid, and the reaction was carried out at 5 °C for 20 minutes. Then, the temperature was raised to room temperature and stirring was continued for 2 hours. After the reaction was completed, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 48 mg of white solid target compound 4, with a yield of 69%.
[0065] Example 5
[0066] Step 1: Dissolve 130 mg of compound 1 in 2.6 mL of dimethyl sulfoxide solution, and add 130 mg of phenethyl isonitrile while stirring at 18 °C for 22 hours. When the reaction color changes from red to colorless, add 15 mL of water to the reaction system, collect the precipitate, and dry it to obtain 160 mg of white solid target compound 2, with a yield of 88%.
[0067] Step 2: Dissolve 120 mg of compound 2 obtained in step 1 in 12 mL of methanol, heat to 64 °C, add 3.8 mL of concentrated hydrochloric acid while stirring, react for 11 hours, cool to room temperature after the reaction is complete, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 34 mg of white powder containing solid compound 3, with a yield of 40%.
[0068] Step 3: 40 mg of compound 3 obtained in Step 2 was slowly added dropwise to 1.3 mL of nitric acid, and the reaction was carried out at 1 °C for 28 minutes. Then, the temperature was raised to room temperature and stirring was continued for 2 hours. After the reaction was completed, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 38 mg of white solid target compound 4, with a yield of 68%.
[0069] Example 6
[0070] Step 1: Dissolve 160 mg of compound 1 in 3.2 mL of dimethyl sulfoxide solution, and add 160 mg of phenethyl isonitrile while stirring at 14 °C for 23 hours. When the reaction color changes from red to colorless, add 16 mL of water to the reaction system, collect the precipitate, and dry it to obtain 200 mg of white solid target compound 2, with a yield of 88%.
[0071] Step 2: Dissolve 140 mg of compound 2 obtained in step 1 in 14 mL of methanol, heat to 55 °C, add 6 mL of concentrated hydrochloric acid while stirring, react for 12 hours, cool to room temperature after the reaction is complete, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 32 mg of white powder containing solid compound 3, with a yield of 32%.
[0072] Step 3: 45 mg of compound 3 obtained in Step 2 was slowly added dropwise to 1.5 mL of nitric acid, and the reaction was carried out at 3 °C for 25 minutes. The temperature was then raised to room temperature and stirring was continued for 2 hours. After the reaction was complete, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 38 mg of the target compound 4 as a white solid, with a yield of 61%.
[0073] Example 7
[0074] Step 1: Dissolve 110 mg of compound 1 in 2.2 mL of dimethyl sulfoxide solution, and add 110 mg of phenethyl isonitrile while stirring at 10 °C for 24 hours. When the reaction color changes from red to colorless, add 11 mL of water to the reaction system, collect the precipitate, and dry it to obtain 140 mg of white solid target compound 2, with a yield of 89%.
[0075] Step 2: Dissolve 100 mg of compound 2 obtained in step 1 in 10 mL of methanol, heat to 70 °C, add 2 mL of concentrated hydrochloric acid while stirring, react for 18 hours, cool to room temperature after the reaction is complete, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 15.6 mg of white powder containing solid compound 3, with a yield of 22%.
[0076] Step 3: Slowly add 35 mg of compound 3 obtained in Step 2 to 1 mL of nitric acid and react at 0 °C for 30 minutes. Then, heat to room temperature and continue stirring for 2 hours. After the reaction is complete, pour the clear solution into ice. A precipitate forms. Collect the precipitate and recrystallize it with distilled water to obtain 27 mg of white solid target compound 4, with a yield of 55%.
[0077] Example 8
[0078] Step 1: Dissolve 190 mg of compound 1 in 3.8 mL of dimethyl sulfoxide solution, and add 190 mg of phenethyl isonitrile while stirring at 20 °C for 20 hours. When the reaction color changes from red to colorless, add 19 mL of water to the reaction system, collect the precipitate, and dry it to obtain 242 mg of white solid target compound 2, with a yield of 90%.
[0079] Step 2: Dissolve 170 mg of compound 2 obtained in step 1 in 10 mL of methanol, heat to 66 °C, add 4.8 mL of concentrated hydrochloric acid while stirring, react for 12 hours, cool to room temperature after the reaction is complete, collect the precipitate, concentrate the mother liquor to obtain crude product, and recrystallize by boiling water to obtain 45 mg of white powder containing solid compound 3, with a yield of 37%.
[0080] Step 3: 50 mg of compound 3 obtained in Step 2 was slowly added dropwise to 1.8 mL of nitric acid, and the reaction was carried out at 4 °C for 22 minutes. The temperature was then raised to room temperature and stirring was continued for 2 hours. After the reaction was complete, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 51 mg of the target compound 4 as a white solid, with a yield of 72%.
[0081] Example 9
[0082] Step 1: Dissolve 140 mg of compound 1 in 2.8 mL of dimethyl sulfoxide solution, and add 140 mg of phenethyl isonitrile while stirring at 16 °C for 21 hours. When the reaction color changes from red to colorless, add 14 mL of water to the reaction system, collect the precipitate, and dry it to obtain 170 mg of white solid target compound 2, with a yield of 86%.
[0083] Step 2: Dissolve 130 mg of compound 2 obtained in step 1 in 13 mL of methanol, heat to 50 °C, add 4 mL of concentrated hydrochloric acid while stirring, react for 15 hours, cool to room temperature after the reaction is complete, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 54 mg of white powder containing solid compound 3, with a yield of 42%.
[0084] Step 3: 42 mg of compound 3 obtained in Step 2 was slowly added dropwise to 1.4 mL of nitric acid, and the reaction was carried out at 2 °C for 26 minutes. Then, the temperature was raised to room temperature and stirring was continued for 1 hour. After the reaction was completed, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 33 mg of white solid target compound 4, with a yield of 57%.
[0085] Example 10
[0086] Step 1: Dissolve 170 mg of compound 1 in 3.4 mL of dimethyl sulfoxide solution, and add 130 mg of phenethyl isonitrile while stirring at 12 °C for 23 hours. When the reaction color changes from red to colorless, add 17 mL of water to the reaction system, collect the precipitate, and dry it to obtain 116 mg of white solid target compound 2, with a yield of 68%.
[0087] Step 2: Dissolve 150 mg of compound 2 obtained in step 1 in 15 mL of methanol, heat to 55 °C, add 4.5 mL of concentrated hydrochloric acid while stirring, react for 15 hours, cool to room temperature after the reaction is complete, collect the precipitate, concentrate the mother liquor to obtain the crude product, and recrystallize by boiling water to obtain 43 mg of white powder containing solid compound 3, with a yield of 40%.
[0088] Step 3: 48 mg of compound 3 obtained in Step 2 was slowly added dropwise to 2 mL of nitric acid, and the reaction was carried out at 3 °C for 24 minutes. Then, the temperature was raised to room temperature and stirring was continued for 3 hours. After the reaction was completed, the clear solution was poured into ice, and a precipitate formed. The precipitate was collected and recrystallized from distilled water to give 45 mg of white solid target compound 4, with a yield of 66%.
[0089] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.
Claims
1. A method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide, characterized in that, include: Step 1: Phenethyl isonitrile and 4,4'-(1,2,4,5-tetraazine-3,6-diyl)bis(1,2,5-oxadiazol-3-amine) undergo a [4+1] cycloaddition reaction in an organic solvent to give a diazapyridine intermediate; Step 2: Hydrolyze the diazapyridine intermediate under concentrated hydrochloric acid to prepare 4,4'-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine); Step 3: Nitrate 4,4'-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) under nitric acid conditions to obtain N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide.
2. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1, characterized in that, In step 1, the organic solvent is dimethyl sulfoxide.
3. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1 or 2, characterized in that, In step 2, the diazapyridine intermediate is dissolved in methanol and then hydrolyzed with hydrochloric acid. The hydrochloric acid mentioned is concentrated hydrochloric acid.
4. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1 or 2, characterized in that, In step 3, the nitric acid is concentrated nitric acid.
5. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1 or 2, characterized in that, The molar ratio between 4,4'-(1,2,4,5-tetraazine-3,6-diyl)bis(1,2,5-oxadiazol-3-amine) and phenethyl isonitrile is 1:(1.5-2).
6. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1 or 2, characterized in that, The molar ratio of the diazapyridine intermediate to hydrochloric acid is 1:(8-12).
7. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1 or 2, characterized in that, The molar ratio of 4,4'-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) to nitric acid is 1:(1-1.2).
8. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1 or 2, characterized in that, Step 1 specifically includes: Phenethyl isonitrile was added to a dimethyl sulfoxide solution of 4,4'-(1,2,4,5-tetraazine-3,6-diyl)bis(1,2,5-oxadiazol-3-amine), and the mixture was stirred at 20–30 °C for 20–24 hours. The solution color changed from red to colorless. Water was added to the reaction system, the precipitate was collected and dried to obtain the diazapyridine intermediate.
9. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1 or 2, characterized in that, Step 2 specifically includes: The diazapyridine intermediate was dissolved in 10–30 mL of methanol, heated to 50–70 °C, and 4–5 mL of concentrated hydrochloric acid was added with stirring. The reaction was carried out for 10–15 hours. After the reaction was completed, the mixture was cooled to room temperature, the precipitate was collected, and the mother liquor was concentrated to obtain the crude product. The crude product was then recrystallized from boiling water to obtain 4,4'-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine).
10. The method for preparing N,N'-[(4-diazo-4H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-4,3-diyl)]dinitroamide according to claim 1 or 2, characterized in that, Step 3 specifically includes: 4,4'-(4-amino-1H-pyrazole-3,5-diyl)bis(1,2,5-oxadiazole-3-amine) was slowly added dropwise to 1–3 mL of concentrated nitric acid and reacted at 0–5 °C for 20–40 minutes. Then the temperature was raised to room temperature and stirring was continued for 1.5–2 hours. After the reaction was completed, the clear solution was poured into ice, and a precipitate was formed. The precipitate was collected and recrystallized from distilled water to obtain the target compound as a white solid.