An imidazopyridazine fused-ring compound, its preparation method and application

Abstract

The application discloses an imidazopyridazine fused ring compound and a preparation method and application thereof. The imidazopyridazine fused ring compound has a tetrazolopyridazinotriazole skeleton, combines tetrazole and pyridazinotriazole, forms an energetic compound with high formation enthalpy, high detonation velocity and good thermal stability, and is more advantageous in energetic material application. The application provides a preparation method of the imidazopyridazine fused ring compound, and the synthesis method process involved has the characteristics of mild reaction condition, high yield, low production cost and easy treatment of waste gas, and the fused ring energetic compound with the tetrazolopyridazinotriazole skeleton can be synthesized through simple steps.

Description

Technical Field

[0001] This invention belongs to the field of energetic materials technology, specifically relating to an imidazopyridazine fused ring compound, its preparation method, and its application. Background Technology

[0002] Energetic materials possess strong destructive and striking capabilities, making them an important energy source for military weapons. In recent years, researchers both domestically and internationally have primarily utilized energetic fused rings composed of imidazoles, triazoles, tetraazoles, and azines as a framework to synthesize a series of energetic compounds with good detonation performance and low sensitivity. Fused ring energetic compounds have become one of the important research directions for novel energetic materials.

[0003] Nitrogen-rich fused-ring energetic compounds exhibit low sensitivity due to strong conjugation effects and intermolecular forces within the ring, while the high heat of formation released by ring breaking and CN / NN bond cleavage gives them excellent detonation performance, high enthalpy of formation, and energy density. Currently, nitrogen-rich fused-ring energetic compounds mainly utilize azoles (such as triazoles and tetraazoles) and azines (such as pyridazines, triazines, and tetraazines) as the backbone. New functional groups (such as ketones, amino groups, and cyano groups) are introduced through NH protonation, transforming them into energetic groups (such as nitramines, nitro groups, and nitroforms). Alternatively, nitration, oxidation, or diazotization reactions can induce cyclic rearrangement to synthesize more stable fused-ring compounds, followed by the conversion of the corresponding functional groups into energetic groups. Among these, triazoles have high nitrogen content, high heat of formation, and structural stability, while tetraazoles possess high detonation performance and high heat of formation, but are more sensitive than triazoles. Based on the advantages and disadvantages of triazoles and tetraazoles, there is a need to develop a novel nitrogen-rich fused-ring energetic compound. Summary of the Invention

[0004] To overcome the problems existing in the prior art, one objective of the present invention is to provide an imidazopyridazine fused-ring compound. A second objective of the present invention is to provide a method for preparing the above-mentioned imidazopyridazine fused-ring compound. A third objective of the present invention is to provide applications of the above-mentioned imidazopyridazine fused-ring compound.

[0005] Based on the advantages and disadvantages of triazoles and tetraazoles, this invention uses tetrazolium-triazole-azines as the framework, which not only ensures the detonation performance of tetraazoles such as high enthalpy of formation, but also gives full play to the thermal stability advantage of triazoles. The provided azole-azines-based nitrogen-rich fused-ring energetic materials have high enthalpy of formation, high detonation velocity and good thermal stability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of this invention provides an imidazopyridazine fused-ring compound, the general structural formula of which is shown in formula (I):

[0008] Ar is a triazole group; R1 is a hydroxyl or amino group.

[0009] Preferably, the structural formula of the imidazopyridazine fused-ring compound is shown in formula (II) or formula (III):

[0010]

[0011] The second aspect of this invention provides a method for preparing the imidazopyridazine fused-ring compound described in the first aspect. When R1 is a hydroxyl group, the preparation method 1 includes the following steps:

[0012] compound a The imidazopyridazine fused-ring compound was prepared by reacting it with a diazotizing reagent and a strong acid 1, followed by reacting it with a diazotizing reagent and a strong acid 2.

[0013] When R1 is an amino group, preparation method 2 includes the following steps:

[0014] The compound a is reacted with a diazotizing agent and a strong acid 3, and then an azide compound and acetic acid are added to the reaction system to carry out reaction 4, thereby obtaining the imidazopyridazine fused ring compound.

[0015] Preferably, the diazotizing agent includes at least one of sodium nitrite and potassium nitrite.

[0016] Preferably, the strong acid includes at least one of concentrated sulfuric acid and concentrated nitric acid.

[0017] Preferably, the azide compound includes at least one of tributyltin azide and sodium azide.

[0018] Preferably, the reaction temperature of reaction 1 is -10 to 10°C, and the reaction time is 2 to 3 hours.

[0019] More preferably, the reaction temperature of reaction 1 is -5 to 5°C.

[0020] Preferably, the preparation method 1 further includes: adding a strong acid to an aqueous solution containing compound a and a diazotizing reagent to carry out reaction 1.

[0021] More preferably, the volume ratio of the strong acid to water is (0.75 to 1.3):1.

[0022] More preferably, the steps of preparation method 1 include: adding concentrated sulfuric acid to an aqueous solution containing compound a and a diazotizing reagent at -10 to 10°C, reacting for 2 to 3 hours, and slowly raising the system to 15 to 25°C while stirring for 4 to 6 hours.

[0023] Preferably, the reaction temperature of reaction 2 is 50–80°C.

[0024] More preferably, the reaction temperature of reaction 2 is 55–70°C.

[0025] Preferably, the reaction time of reaction 2 is 30 to 120 minutes.

[0026] More preferably, the reaction time of reaction 2 is 45 to 90 minutes.

[0027] Preferably, the preparation method 1 further includes the following steps: after reaction 2, adding dilute sulfuric acid.

[0028] Preferably, the reaction temperature of reaction 3 is 10-25°C and the reaction time is 30-120 min.

[0029] More preferably, the reaction temperature of reaction 3 is 15–20°C, and the reaction time is 45–90 min.

[0030] Preferably, the preparation method 2 further includes: adding an aqueous solution of the diazotizing reagent to a strong acid and mixing, then adding compound a, and carrying out reaction 3.

[0031] More preferably, the aqueous solution of the diazotizing reagent is added to a strong acid and mixed at -10 to 0°C.

[0032] Preferably, reaction 4 is performed by reacting at -10 to 0°C for 20 to 40 minutes, followed by reacting at 15 to 25°C for 4 to 6 hours.

[0033] Preferably, in reaction 1, the molar ratio of compound a to the diazotizing agent is 1:(12-18).

[0034] More preferably, in reaction 1, the molar ratio of compound a to the diazotizing agent is 1:(13-16).

[0035] Preferably, in reaction 3, the molar ratio of compound a to the diazotizing agent is 1:(8-14).

[0036] More preferably, in reaction 3, the molar ratio of compound a to the diazotizing agent is 1:(10-12).

[0037] Preferably, the molar ratio of compound a to the azide compound is 1:(12-18).

[0038] The third aspect of the present invention provides the use of the imidazopyridazine fused-ring compound or its energetic salt described in the first aspect in energetic materials.

[0039] Preferably, the energetic salt is selected from ammonium salts, hydroxylamine salts, or hydrazine salts.

[0040] Preferably, the use of the imidazopyridazine fused-ring compound or its energetic salt in explosives.

[0041] The beneficial effects of this invention are:

[0042] (1) The present invention provides an imidazopyridazine fused ring compound having a tetrazolopyridazintriazole skeleton, which combines tetraazole and pyridazintriazole to form an energetic compound with high enthalpy of formation, high detonation velocity and good thermal stability, making it more advantageous in energetic material applications.

[0043] (2) The present invention provides a method for preparing the imidazopyridazine fused-ring compound. The synthetic method involved has the characteristics of mild reaction conditions, high yield, low production cost and easy waste gas treatment. The fused-ring energetic compound with a tetrazolopyridazine triazole skeleton can be synthesized through simple steps. Attached Figure Description

[0044] Figure 1 This is a crystal structure diagram of compound 2 of the present invention;

[0045] Figure 2 This is a crystal structure diagram of compound 3 of the present invention;

[0046] Figure 3 Here is the DSC diagram of compound 2 of the present invention;

[0047] Figure 4 Here is the DSC chromatogram of compound 3 of the present invention;

[0048] Figure 5 The infrared spectrum of compound 2 of the present invention;

[0049] Figure 6 This is the infrared spectrum of compound 3 of the present invention. Detailed Implementation

[0050] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels or prepared and isolated through simple synthesis; unless otherwise specified, the processes employed are conventional processes in the art.

[0051] This invention designs and synthesizes 8H-tetrazo[1,5-b][1,2,3]triazolo[4,5-d]pyridazin-6-ol (i.e., compound 2) and 9H-tetrazo[1,5-b][1,2,3]triazolo[4,5-d]pyridazin-6-amine (i.e., compound 3) with a tetrazolo[1,5-b][1,2,3]triazolo[4,5-d]pyridazin-6-amine as the backbone. The synthetic reaction formulas are as follows:

[0052]

[0053] The specific steps for synthesizing compounds 2 and 3 are as follows:

[0054] Step 1) Preparation of compound 2: Add compound 1 to NaNO2 solution, then slowly add concentrated sulfuric acid, and react at 0-10℃ for 2-3 hours. After the reaction is completed, heat at 60℃ for 1 hour. Compound 2 can be obtained by extraction with ethyl acetate, drying with anhydrous magnesium sulfate, and rotary evaporation.

[0055] Step 2) Preparation of compound 3: NaNO2 was slowly added to concentrated sulfuric acid, and then compound 1 was slowly added to the mixed solution. The temperature was maintained between 15 and 20°C. CH3COOH was added, the system was cooled to 0°C, NaN3 was added, and the mixture was stirred at room temperature for 4 to 6 hours. Compound 3 was obtained by extraction with ethyl acetate, drying with anhydrous magnesium sulfate, and rotary evaporation.

[0056] In a preferred embodiment of the present invention, in step (1), when mixing 1H-[1,2,3]triazolo[4,5-d]pyridazine-4,7-diamine and NaNO2 solution, the temperature should be below 0°C. When adding concentrated sulfuric acid, it should be added slowly, and the temperature should be controlled not to exceed 10°C. The reaction time is 2 to 3 hours. The molar ratio of NaNO2 to 1H-[1,2,3]triazolo[4,5-d]pyridazine-4,7-diamine is 1:14.9 to 15, and the amount of concentrated sulfuric acid is 10 ml.

[0057] In a preferred embodiment of the present invention, in step (1), the reaction temperature is 60°C and the reaction time is 1 hour after adding concentrated sulfuric acid and heating. The extraction solvent is ethyl acetate and the amount is 150 ml.

[0058] In a preferred embodiment of the present invention, in step (2), when mixing NaNO2 and concentrated sulfuric acid, the temperature should be below 0°C. When adding concentrated sulfuric acid, it should be added slowly, and the temperature should be controlled not to exceed 10°C. When adding 1H-[1,2,3]triazolo[4,5-d]pyridazine-4,7-diamine, the temperature should be maintained at 15-20°C, and the mixing time is 1 hour. The molar ratio of NaNO2 and 1H-[1,2,3]triazolo[4,5-d]pyridazine-4,7-diamine is 1:4.24, and the amount of concentrated sulfuric acid is 12.5 ml.

[0059] In a preferred embodiment of the present invention, in step (2), CH3COOH is added below 0°C, NaN3 is mixed with a small amount of deionized water and then slowly added dropwise to the reaction system, the reaction time is 4 to 6 hours, the amount of CH3COOH is 12.5 ml, the amount of NaN3 is 1.3 g, and the extraction solvent is ethyl acetate with a volume of 600 ml.

[0060] Example 1

[0061] This embodiment provides 8H-tetrazo[1,5-b][1,2,3]triazolo[4,5-d]pyridazin-6-ol (i.e., compound 2) with a tetrazo[pyridazin]triazole as the skeleton. The specific synthetic steps are as follows:

[0062]

[0063] S1, 1H-[1,2,3]triazolo[4,5-d]pyridazine-4,7-diamine (0.69 g, 4.6 mmol) and NaNO2 (4.75 g, 68.8 mmol) were dissolved in water (10 ml) and cooled to 0 °C in an ice-salt bath. 98% sulfuric acid (10 ml) was slowly added dropwise to the yellow suspension while maintaining the temperature below 10 °C. Gas (NO2) was released, and a pale yellow solid was also released. The system was slowly raised to room temperature and stirred for 4-6 h. The solution was then heated at 60 °C for 1 h, and the pale yellow solid disappeared, yielding a yellow solution.

[0064] S2. After cooling to room temperature, sulfuric acid (20%) was added, and the solution gradually turned pale yellow until no more obvious NO2 gas evolution was observed. The aqueous solution was extracted with ethyl acetate (150 ml), and the organic phase was dried with anhydrous magnesium sulfate. The removal of the solvent resulted in the formation of a white product, namely compound 2 (0.7 g, 3.9 mmol, 85%).

[0065] The crystal structure of compound 2 is shown in [reference needed]. Figure 1 The infrared spectrum of compound 2 is as follows: Figure 3 As shown; the density of compound 2, measured by a vacuum density meter, is 1.80 g·cm³. -1 Compound 2, as measured by DSC, has a decomposition temperature of 216.6℃ (e.g., ...). Figure 5 As shown in the figure, its enthalpy of formation is calculated to be 819.88 kJ·mol⁻¹. -1 The detonation velocity is 8304 m / s. -1 The detonation pressure is 26.7 GPa. While ensuring the high enthalpy of formation of compound 2, it also improves the thermal stability of the compound. It is a high-energy-density material with high enthalpy of formation and good thermal stability, and has great potential in the field of explosives.

[0066] Example 2

[0067] This embodiment provides 9H-tetrazo[1,5-b][1,2,3]triazolo[4,5-d]pyridazine-6-amine (i.e., compound 3), and its specific synthetic steps are as follows:

[0068]

[0069] S1. Place 12.5 ml of 98% sulfuric acid in a 100 ml three-necked flask and cool to 0 °C in an ice-salt bath. Dissolve 1 g of NaNO2 (14 mmol) in a small amount of water (3 ml) and slowly add it dropwise to the concentrated sulfuric acid while maintaining the temperature between 15 and 20 °C. A large amount of NO2 gas is released. After stirring for 10 min, add 0.5 g of 4,7-diamino-triazolo[4,5-d]pyridazine (1.28 mmol) in portions slowly to the mixture. Slowly raise the system to room temperature and keep stirring for 1-2 h. The solution gradually becomes clear until it becomes a pale yellow solution.

[0070] S2. Add CH3COOH (12.5 ml), and cool the system to 0°C again using an ice-salt bath. Weigh out NaN3 (1.3 g), dissolve it in water (8 ml) to prepare a solution, and slowly add it to the solution. The solution color will darken. Maintain the temperature below 0°C and stir for 30 min. Then stir at room temperature for 4-6 h. After the reaction is complete, pour the solution into ice water (50 ml), stir for a while, and then extract with ethyl acetate (600 ml). Dry the organic phase with anhydrous magnesium sulfate. Concentrate the solution under vacuum to about 2 ml, wash with a small amount of water, filter, and dry to obtain a pale yellow solid, namely compound 3 (0.1 g, 0.55 mmol, 42.9%).

[0071] The crystal structure of compound 3 is shown in [reference needed]. Figure 2 The infrared spectrum of compound 3 is as follows: Figure 4 As shown; the density of compound 3, measured by a vacuum density meter, is 1.786 g·cm³. -1 Compound 3, as measured by DSC, has a decomposition temperature of 318.0℃ (e.g., ...). Figure 6 As shown in the figure, its enthalpy of formation is calculated to be 685.71 kJ·mol⁻¹. -1 The detonation velocity is 8075 m / s. -1 With a detonation pressure of 23.5 GPa, it balances the detonation performance and formation enthalpy of the compound while ensuring the high thermal stability of compound 3. It is a high-energy-density material with good thermal stability and has great potential in the field of explosives.

[0072] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An imidazopyridazine fused ring compound, characterized by, The structural general formula of the imidazopyridazine fused ring compound is shown as formula (I): Formula (I); A specific structural formula of formula (I) is shown as formula (II) or formula (III): formula (II), formula (III).

2. The method for preparing the imidazopyridazine fused-ring compound according to claim 1, characterized in that, When formula (I) is selected from formula (II), the preparation method comprises the following steps: Compound a with diazotization reagent and strong acid, then with diazotization reagent and strong acid again, and after reaction 2, dilute sulfuric acid is added to produce the imidazopyridazine fused ring compound; When formula (I) is selected from formula (III), the preparation method comprises the following steps: The compound a is reacted with a diazotization reagent and a strong acid to obtain the imidazopyridazine fused ring compound.

3. The method for preparing the imidazopyridazine fused-ring compound according to claim 2, characterized in that, The diazotization reagent is at least one selected from sodium nitrite and potassium nitrite; And / or, the strong acid is at least one selected from concentrated sulfuric acid and concentrated nitric acid.

4. The method for preparing the imidazopyridazine fused-ring compound according to claim 2, characterized in that, The azide compound is at least one selected from tributyltin azide and sodium azide.

5. The method for preparing the imidazopyridazine fused-ring compound according to claim 2, characterized in that, The reaction temperature of the reaction 1 is -10-10℃, and the reaction time is 2-3h. And / or, the reaction temperature of the reaction 2 is 50-80℃, and the reaction time is 30-120 min.

6. The method for preparing the imidazopyridazine fused-ring compound according to claim 2, characterized in that, The reaction temperature of the reaction 3 is 10-25℃, and the reaction time is 30-120 min. And / or, the reaction 4 is: first reacting at -10-0℃ for 20-40 min, and then reacting at 15-25℃ for 4-6h.

7. The method for preparing the imidazopyridazine fused-ring compound according to claim 2, characterized in that, In the reaction 1, the molar ratio of the compound a to the diazotization reagent is 1:(12-18).

8. The method for preparing the imidazopyridazine fused-ring compound according to claim 2, characterized in that, In the reaction 3, the molar ratio of the compound a to the diazotization reagent is 1:(8-14).

9. Application of the imidazopyridazine fused ring compound or an energetic salt thereof in claim 1 in an energetic material.

Images