Imidazopyridazine fused ring compound as well as preparation method and application thereof

Abstract

The invention discloses an imidazopyridazine fused ring compound and a preparation method and application thereof.The imidazopyridazine fused ring compound has a tetrazolo-pyridazinotriazole skeleton, tetrazole and pyridazinotriazole are combined, and an energetic compound with high enthalpy of formation, high detonation velocity and good thermal stability is formed; therefore, the material has more advantages in energetic material application. The invention provides the preparation method of the imidazopyridazine fused ring compound, the related synthesis method has the characteristics of mild reaction conditions, high yield, low production cost and easy waste gas treatment, and the fused ring energetic compound with the tetrazolopyridazine triazole skeleton can be synthesized through simple steps.

Description

Technical Field

[0001] The invention belongs to the technical field of energetic materials, and specifically relates to an imidazopyridazine fused ring compound and a preparation method and application thereof. Background Art

[0002] Energetic materials have strong damage and strike capabilities and are an important energy source for military weapons. In recent years, researchers at home and abroad have mainly used energetic fused rings combined with imidazole, triazole, tetrazole and azine as the skeleton 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 of new energetic materials.

[0003] Nitrogen-rich fused ring energetic compounds have low sensitivity due to their strong conjugation effect and intermolecular forces within the ring. At the same time, the high heat of formation released by the breakage of the ring and the breakage of the CN and NN bonds makes them have good detonation performance, high formation enthalpy and energy density. At present, nitrogen-rich fused ring energetic compounds are mainly composed of azoles (such as triazoles and tetrazoles) and azines (such as pyridazine, triazine, tetrazine) as the skeleton, and new functional groups (such as keto, amino, cyano, etc.) are introduced through NH protonation and then converted into energetic groups (such as nitramine, nitro, nitroform, etc.); or the compounds are rearranged into rings to synthesize more stable fused ring compounds through nitration and oxidation or diazotization reactions, and then the corresponding groups are converted into energetic groups. Among them, triazole has a high nitrogen content and high heat of formation, and a stable structure, while tetrazolyl has high detonation performance and high heat of formation, but its sensitivity is higher than that of triazole. Based on the advantages and disadvantages of triazole and tetrazolyl, it is necessary to develop a new type of nitrogen-rich fused ring energetic compound. Summary of the invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, one of the purposes of the present invention is to provide an imidazopyridazine fused ring compound. The second purpose of the present invention is to provide a method for preparing the above-mentioned imidazopyridazine fused ring compound. The third purpose of the present invention is to provide an application of the above-mentioned imidazopyridazine fused ring compound.

[0005] Based on the advantages and disadvantages of triazole and tetrazole, the present invention uses tetrazolyl-triazoloazine compounds as the skeleton, which not only ensures the detonation performance such as high formation enthalpy of tetrazole compounds, but also can give full play to the thermal stability advantages of triazole compounds. The provided azole-triazine nitrogen-rich fused ring energetic material has high formation enthalpy, high detonation velocity and good thermal stability.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

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

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

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

[0010]

[0011] The second aspect of the present invention provides a method for preparing the imidazopyridazine fused ring compound of the first aspect, when R1 is a hydroxyl group, the preparation method 1 comprises the following steps:

[0012] Compound a reacting with a diazotizing agent and a strong acid 1, and then reacting with a diazotizing agent and a strong acid 2 to obtain the imidazopyridazine fused ring compound;

[0013] When R1 is amino, preparation method 2 comprises the following steps:

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

[0015] Preferably, the diazotizing agent comprises 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 the reaction 1 is -5 to 5°C.

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

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

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

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

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

[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 steps of the preparation method 2 further include: adding an aqueous solution of a diazotizing agent into a strong acid and mixing, and then adding compound a to carry out reaction 3.

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

[0032] Preferably, the reaction 4 is: first react at -10 to 0°C for 20 to 40 minutes, and then react at 15 to 25°C for 4 to 6 hours.

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

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

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

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

[0037] Preferably, the molar ratio of the 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 energy-containing salt is selected from ammonium salts, hydroxylamine salts or hydrazine salts.

[0040] Preferably, the imidazopyridazine fused ring compound or its energetic salt is used in explosives.

[0041] The beneficial effects of the present invention are:

[0042] (1) The present invention provides an imidazopyridazine fused ring compound having a tetrazopyridazinetriazole skeleton, and combining tetrazolyl and pyridazinetriazole to form an energetic compound with higher formation enthalpy, higher detonation velocity and good thermal stability, making it more advantageous in the application of energetic materials.

[0043] (2) The present invention provides a method for preparing the imidazopyridazine fused ring compound. The synthetic method and process 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 tetrazopyridazine triazole skeleton can be synthesized through simple steps. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0047] Figure 4 It is the DSC chart of compound 3 of the present invention;

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

[0049] Figure 6 It is the infrared spectrum of compound 3 of the present invention. DETAILED DESCRIPTION

[0050] The present invention is further described in detail below through specific examples. The raw materials used in the following examples, unless otherwise specified, can be obtained from conventional commercial sources or prepared and separated by simple synthesis; the processes used, unless otherwise specified, are conventional processes in the art.

[0051] The present 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 tetrazopyridazinetriazole as the skeleton, and the synthesis reaction formula thereof is as follows:

[0052]

[0053] The synthetic method of compound 2 and compound 3 has the following specific steps:

[0054] Step 1) Preparation of Compound 2: Compound 1 is added to a NaNO2 solution, and then concentrated sulfuric acid is slowly added dropwise, and the reaction is carried out at 0-10°C for 2-3 hours. After the reaction is completed, the reaction is heated at 60°C for 1 hour, and the compound 2 is obtained by extraction with ethyl acetate, drying with anhydrous magnesium sulfate, and rotary evaporation.

[0055] Step 2) Preparation of compound 3: Slowly add NaNO2 to concentrated sulfuric acid, then slowly add compound 1 to the mixed solution, maintain the temperature between 15 and 20°C, add CH3COOH, cool the system to 0°C, add NaN3, stir at room temperature for 4 to 6 hours, extract with ethyl acetate, dry with anhydrous magnesium sulfate, and rotary evaporate to obtain compound 3.

[0056] As 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, and when adding concentrated sulfuric acid, it should be added slowly, the temperature should be controlled not to exceed 10°C, and the reaction time is 2 to 3 hours; the molar ratio of NaNO2 and 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] As a preferred embodiment of the present invention, in step (1), the reaction temperature is 60° C. when concentrated sulfuric acid is added dropwise and heated, the reaction time is 1 hour, and the extraction solvent is ethyl acetate in an amount of 150 ml.

[0058] As 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 is 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] As 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 and the amount is 600 ml.

[0060] Example 1

[0061] This example provides 8H-tetrazo[1,5-b][1,2,3]triazolo[4,5-d]pyridazine-6-ol (i.e., compound 2) with tetrazopyridazinotriazole as the skeleton, and the specific synthesis 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, and the temperature was maintained at no more than 10°C. Gas (NO2) and a light yellow solid were precipitated at the same time. The system was slowly warmed to room temperature and stirred for 4-6 hours; the solution was heated at 60°C for 1 hour, the light yellow solid disappeared, and a yellow solution was obtained;

[0064] S2. After cooling to room temperature, sulfuric acid (20%) was added, and the color of the solution gradually changed to light 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 over anhydrous magnesium sulfate; 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 Figure 1 ; The infrared spectrum of compound 2 is as follows Figure 3 As shown; the density of compound 2 was measured by vacuum density instrument and its density was 1.80 g·cm -1 The decomposition temperature of compound 2 was 216.6°C ( Figure 5 As shown in Figure 2, the enthalpy of formation is calculated to be 819.88 kJ·mol -1 , the detonation speed is 8304m·s -1 The detonation pressure is 26.7 GPa. While ensuring the high formation enthalpy of compound 2, the thermal stability of the compound is improved. It is a high-energy density material with high formation enthalpy and good thermal stability, and has great potential in the field of explosives.

[0066] Example 2

[0067] This example provides 9H-tetrazo[1,5-b][1,2,3]triazolo[4,5-d]pyridazine-6-amine (ie, compound 3), and the specific synthesis steps are as follows:

[0068]

[0069] S1. 98% sulfuric acid (12.5 ml) was placed in a 100 ml three-necked flask and cooled to 0°C in an ice-salt bath. NaNO2 (1 g, 14 mmol) was dissolved in a small amount of water (3 ml) and slowly added dropwise to concentrated sulfuric acid, maintaining the temperature between 15 and 20°C. A large amount of NO2 gas was precipitated. After stirring for 10 min, 4,7-diamino-triazolo[4,5-d]pyridazine (0.5 g, 1.28 mmol) was slowly added to the mixture in batches. The system was slowly raised to room temperature and stirred for 1-2 h. The solution gradually became clear until it became a light yellow solution.

[0070] S2, add CH3COOH (12.5ml), cool the system to 0℃ again with ice-salt bath, weigh NaN3 (1.3g) and dissolve it in water (8ml) to make a solution and slowly add it to the solution, the color of the solution becomes darker, maintain the temperature not exceeding 0℃, keep warm and stir for 30min; then stir at room temperature for 4-6h. After the reaction is completed, pour the solution into ice water (50ml), stir for a while and extract with ethyl acetate (600ml), dry the organic phase with anhydrous magnesium sulfate; vacuum concentrate the solution to about 2ml, wash with a small amount of water, filter and dry to obtain a light yellow solid, i.e. compound 3 (0.1g, 0.55mmol, 42.9%).

[0071] The crystal structure of compound 3 is shown in Figure 2 ; The infrared spectrum of compound 3 is as follows Figure 4 As shown; the crystal density of compound 3 measured by vacuum density instrument is 1.786g·cm -1 The decomposition temperature of compound 3 was 318.0°C ( Figure 6 As shown in Figure 2, the calculated enthalpy of formation is 685.71 kJ·mol -1 , the detonation speed is 8075m·s -1 The detonation pressure is 23.5 GPa. While ensuring the high thermal stability of compound 3, the detonation performance and formation enthalpy of the compound are balanced. 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 implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An imidazopyridazine fused ring compound, characterized in that: The general structural formula of the imidazopyridazine fused ring compound is shown in formula (I): Wherein Ar is a triazole group; R1 is a hydroxyl group or an amino group.

2. The imidazopyridazine fused ring compound according to claim 1, characterized in that: The structural formula of the imidazopyridazine fused ring compound is as shown in formula (II) or formula (III):

3. The method for preparing the imidazopyridazine fused ring compound according to claim 1 or 2, characterized in that: When R1 is a hydroxyl group, the preparation method comprises the following steps: Compound a reacting with a diazotizing agent and a strong acid 1, and then reacting with a diazotizing agent and a strong acid 2 to obtain the imidazopyridazine fused ring compound; When R1 is amino, the preparation method comprises the following steps: The compound a is reacted with a diazotizing agent and a strong acid to perform reaction 3, and then an azide compound and acetic acid are added to the reaction system to perform reaction 4 to obtain the imidazopyridazine fused ring compound.

4. The method for preparing the imidazopyridazine fused ring compound according to claim 3, characterized in that: The diazotizing agent includes at least one of sodium nitrite and potassium nitrite; And / or, the strong acid includes at least one of concentrated sulfuric acid and concentrated nitric acid.

5. The method for preparing the imidazopyridazine fused ring compound according to claim 3, characterized in that: The azide compound includes at least one of tributyltin azide and sodium azide.

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

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

8. The method for preparing the imidazopyridazine fused ring compound according to claim 3, characterized in that: In the reaction 1, the molar ratio of the compound a to the diazotizing agent is 1:(12-18).

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

10. Use of the imidazopyridazine fused ring compound or its energetic salt according to claim 1 or 2 in energetic materials.

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