Application of electrochemistry in self-coupling of pyrimidine compound under catalyst-free condition, pyrimidine self-coupling compound, perchlorate derivative of pyrimidine self-coupling compound and preparation method and application of pyrimidine self-coupling compound and perchlorate derivative of pyrimidine self-coupling compound

Abstract

The invention relates to the technical field of energetic materials, in particular to application of electrochemistry in self-coupling of pyrimidine compounds under the catalyst-free condition, a pyrimidine self-coupling compound, a perchlorate derivative of the pyrimidine self-coupling compound and a preparation method and application of the pyrimidine self-coupling compound and the perchlorate derivative of the pyrimidine self-coupling compound. The invention provides an application of electrochemistry in self-coupling of pyrimidine compounds under a catalyst-free condition. The C-C self-coupling reaction of the pyrimidine compound is electrochemically driven under the condition of no catalyst, the product selectivity is high, the direct C-C self-coupling reaction of the pyrimidine ring in the pyrimidine compound is electrochemically driven under the condition of no catalyst, the bicyclic pyrimidyl energetic skeleton is constructed, and the product selectivity is high. Transition metal catalysis is not needed, reaction conditions are simple, product selectivity is high, side reactions are few, and the application range of electrochemistry in explosive synthesis is widened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energetic materials, and particularly relates to application of electrochemistry in self-coupling of pyrimidine compounds under catalyst-free conditions, pyrimidine self-coupling compounds, perchlorate derivatives thereof, and preparation methods and application thereof. BACKGROUND

[0002] As a typical six-membered aromatic nitrogen heterocycle, pyrimidine not only has good thermodynamic stability, but also has many modifiable sites. In addition, the wide application of pyrimidine derivatives in alkaloids, drugs and functional materials provides valuable molecular design concepts and synthesis strategies for energetic compound research.

[0003] At present, the C-H activation strategy of C-C bond in pyridine compounds mainly uses metal catalysts containing Pd, Ru, Rh, Ni and the like to activate C-H bond. For example, a related document discloses a method for oxidative dehydrogenation coupling to synthesize alkyl aryl pyridine compounds, which uses substituted aryl pyridine compounds and alkyl borate compounds as raw materials, and performs constant current electrolysis reaction in an organic solvent in the presence of a rhodium catalyst and an additive, to obtain alkyl aryl pyridine compounds, wherein the additive is selected from KPF6, n Bu4NPF6, n Bu4NOAc, NaOPiv, KOPiv, n Bu4NBF4 or NaBF4. However, due to the nitrogen sites in pyrimidine compounds, the catalyst is often poisoned to lose catalytic activity, which easily changes the mechanism and path of the reaction, increases the side reaction, and reduces the selectivity of the product. SUMMARY

[0004] In view of this, the present application aims to provide application of electrochemistry in C-C self-coupling of pyrimidine compounds under catalyst-free conditions, pyrimidine self-coupling compounds, perchlorate derivatives thereof, and preparation methods and application thereof. The present application uses electrochemistry to drive the C-C self-coupling reaction of pyrimidine compounds under catalyst-free conditions, and the selectivity of the product is high.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: The present application provides application of electrochemistry in self-coupling of pyrimidine compounds under catalyst-free conditions.

[0006] Preferably, the pyrimidine compounds include 2,4,6-triaminopyrimidine.

[0007] The present application also provides a pyrimidine self-coupling compound, which has the structure shown in formula I: Formula I.

[0008] The application further provides a preparation method of the pyrimidine self-coupling compound, comprising the following steps: mixing 2,4,6-triaminopyrimidine, an alkaline reagent and a solvent, and performing an electrochemical C-C bond coupling reaction to obtain the pyrimidine self-coupling compound.

[0009] Preferably, the molar ratio of the 2,4,6-triaminopyrimidine and the alkaline reagent is 1:0.5-100. The alkaline reagent comprises an inorganic alkaline reagent and / or an organic base. The solvent is water and / or an organic solvent, and the organic solvent comprises acetonitrile and / or an alcohol solvent.

[0010] Preferably, the electrochemical C-C bond coupling reaction is performed under the following conditions: the anode comprises one or more of graphite, tungsten oxide, silicon-based material and tin-based material; the cathode comprises one or more of platinum, graphite, carbon cloth and nickel foam; the temperature is 0-100 DEG C; the voltage is 0.1-5 V; and the time is 1-48 h.

[0011] The application further provides a perchlorate derivative of the pyrimidine self-coupling compound, which has the structure shown in formula II. Formula II.

[0012] The application further provides a preparation method of the perchlorate derivative of the pyrimidine self-coupling compound, comprising the following steps: recrystallizing the pyrimidine self-coupling compound in a perchloric acid solution to obtain the perchlorate derivative of the pyrimidine self-coupling compound.

[0013] Preferably, the mass concentration of the perchloric acid solution is 20-90%. The ratio of the amount of substance of the pyrimidine self-coupling compound to the volume of the perchloric acid solution is 1 mol:0.05-2.5 L. The recrystallization is performed at a temperature of 0-100 DEG C for 1 min-48 h.

[0014] The application further provides application of the pyrimidine self-coupling compound or the perchlorate derivative of the pyrimidine self-coupling compound in explosives, solid propellant adjuvants or combustion catalysts. The application provides application of electrochemistry in self-coupling of pyrimidine compounds without catalysts. The application directly drives C-C self-coupling reaction of a pyrimidine ring in a pyrimidine compound by electrochemistry without catalysts, and constructs a double-ring pyrimidine-based energetic skeleton. The product has high selectivity and few side reactions. The reaction condition is simple, and the application range of electrochemistry in explosive synthesis is expanded.

[0015] The pyrimidine self-coupling compound (denoted as HABP) provided by the application has a double-ring pyrimidine group energetic skeleton, is an excellent explosive molecular skeleton structure rich in nitrogen and heat-resistant and high-energy, and based on the HABP, an excellent energetic material HABPTP with excellent comprehensive performance can be obtained, and the HABPTP has a good application prospect in the preparation of explosives.

[0016] The application realizes the direct C-C self-coupling reaction of a pyrimidine ring by electrochemically driving C-H bond activation under the condition of no catalyst, constructs a C-C coupling energetic skeleton, and obtains a pyrimidine self-coupling compound, and the application range of electrochemistry in the synthesis of an energetic material skeleton is expanded. The preparation method of the pyrimidine self-coupling compound provided by the application has high product selectivity, is environment-friendly, has mild reaction conditions, high atom economy, can avoid the use of harmful redox agents and extreme reaction conditions, greatly reduces the production cost, and is suitable for industrial production.

[0017] The perchlorate derivative (denoted as HABPTP) of the pyrimidine self-coupling compound provided by the application has a double-ring pyrimidine group energetic skeleton, and the introduction of perchloric acid greatly improves the energetic performance, the HABPTP provided by the application has high density, high thermal decomposition temperature, high enthalpy of formation, large detonation velocity, high detonation pressure and low impact sensitivity, and exhibits excellent energetic performance, and the comprehensive performance is better than that of hexogen, and the HABPTP can be used as a high-energy explosive.

[0018] The pyrimidine self-coupling compound and perchloric acid are self-assembled to prepare the perchlorate derivative of the pyrimidine self-coupling compound, and the introduction of perchloric acid greatly enhances the energetic performance; and the preparation method provided by the application has simple process, simple operation, low production cost and is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Figure 1 is a single crystal test crystal structure analysis diagram of HABPTP·2H2O, wherein (a) is a HABP4 + Figure 1 is a single crystal test crystal structure analysis diagram of HABPTP·2H2O, wherein (a) is a HABP4 DETAILED DESCRIPTION

[0020] The application provides an application of electrochemistry in self-coupling of pyrimidine compounds under the condition of no catalyst. In the application, the pyrimidine compounds can include 2,4,6-triaminopyrimidine.

[0021] The application further provides a pyrimidine self-coupling compound having a structure shown in formula I. Formula I; The chemical name of the formula I is 2,2',4,4',6,6'-hexamino-[5,5'-bipyrimidine].

[0022] The present application also provides a preparation method of the pyrimidine self-coupling compound in the above technical solution, comprising the following steps: mixing 2,4,6-triaminopyrimidine, an alkaline reagent and a solvent, and performing an electrochemical C-C bond coupling reaction to obtain the pyrimidine self-coupling compound.

[0023] Unless otherwise specified, the materials and equipment used in the present application are commercially available in the art.

[0024] In the present application, the alkaline reagent can include an inorganic alkaline reagent and / or an organic base. In the present application, the inorganic alkaline reagent can include a hydroxide and / or a carbonate; the hydroxide can include an alkali metal hydroxide, which can specifically include sodium hydroxide and / or potassium hydroxide; the carbonate can include an alkali metal carbonate, which can specifically include sodium carbonate and / or potassium carbonate. In the present application, the organic alkaline reagent includes an organic amine, which can specifically include one or more of triethylamine, diethylamine and pyridine.

[0025] In the present application, the molar ratio of 2,4,6-triaminopyrimidine to the alkaline reagent can be 1:0.5-100, and can also be 1:1-10, which can specifically be 1:0.5, 1:1, 1:1.2, 1:1.5, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90 or 1:100.

[0026] In the present application, the solvent can be water and / or an organic solvent, and the organic solvent includes one or more of acetonitrile, an alcohol solvent, an amide solvent, dimethyl sulfoxide and an ionic liquid; the alcohol solvent can include methanol and / or ethanol; the amide solvent can include dimethylformamide and / or dimethylacetamide; the ionic liquid can include one or more of an imidazole ionic liquid, a pyrrole ionic liquid and a quaternary ammonium ionic liquid. In the present application, the concentration of the alkaline reagent in the solvent can be 0.1-20 M (mol / L), and can also be 2-10 M, which can specifically be 0.1 M, 0.5 M, 1 M, 1.5 M, 2 M, 3 M, 4 M, 5 M, 8 M, 10 M, 12 M, 15 M, 18 M, 19 M or 20 M.

[0027] In the present application, the mixing can include mixing the alkaline reagent with the solvent to obtain an alkali liquor, and mixing 2,4,6-triaminopyrimidine with the alkali liquor.

[0028] In the present application, the conditions of the electrochemical C-C bond coupling reaction can include: the anode comprises one or more of graphite, tungsten oxide, niobium tungsten oxide, silicon-based material and tin-based material, which can be specifically graphite; the present application does not have special limitations on the tungsten oxide, which can be any tungsten oxide known to those skilled in the art that can be used as an anode; the niobium tungsten oxide can include Nb 18 W 16 O 93 ; the silicon-based material can include one or more of silicon carbon, silicon monoxide and porous silicon material; the tin-based material can include one or more of tin metal, tin-based alloy, tin-based oxide and tin / carbon composite material, and the present application does not have special limitations on the tin-based alloy, tin-based oxide and tin / carbon composite material, which can be any tin-based alloy, tin-based oxide and tin / carbon composite material known to those skilled in the art that can be used as an anode; the cathode comprises one or more of platinum, graphite, carbon cloth and nickel foam, which can be specifically platinum; the temperature is 0-100℃, which can also be 20-50℃, and can be specifically 0℃, 10℃, 20℃, 25℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃; the voltage is 0.1-5V, which can also be 1.5-3V, and can be specifically 0.1V, 0.5V, 1V, 1.5V, 2V, 2.5V, 3V, 3.5V, 4V, 4.5V or 5V; the time is 1-48h, which can also be 15-30h, and can be specifically 1h, 5h, 10h, 15h, 20h, 24h, 30h, 35h, 40h, 45h or 48h. In the present application, the preparation route of the pyrimidine self-coupling compound is as follows: .

[0029] After the electrochemical C-C bond coupling reaction is completed, the present application can further include: concentrating the electrolyte obtained by the electrochemical C-C bond coupling reaction, then performing solid-liquid separation, washing the obtained solid component and drying to obtain a pyrimidine self-coupling compound. The present application does not have special limitations on the solid-liquid separation, which can be any solid-liquid separation method known to those skilled in the art, such as filtration, suction filtration or centrifugal separation. In the present application, the washing can include water washing and ethanol washing in sequence. In the present application, the temperature of the drying can be 15-100℃, which can also be 50-80℃, and can be specifically 15℃, 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃; the present application does not have special limitations on the time of the drying, which can be dried to a constant weight.

[0030] The present application also provides a perchlorate salt derivative of a pyrimidine self-coupling compound, which has the structure shown in formula II: Formula II; The chemical name of the formula II is 2,2',4,4',6,6'-hexamino-[5,5'-bipyrimidine]-1,1',3,3'-tetraium perchlorate.

[0031] The application further provides a preparation method of the perchlorate salt derivative of the pyrimidine self-coupling compound in the above technical solution, comprising the following steps: recrystallizing the pyrimidine self-coupling compound in the above technical solution in a perchloric acid solution to obtain the perchlorate salt derivative of the pyrimidine self-coupling compound.

[0032] In the application, the mass concentration of the perchloric acid solution can be 20-90%, and can also be 50-80%, and can be specifically 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%.

[0033] In the application, the ratio of the amount of substance of the pyrimidine self-coupling compound to the volume of the perchloric acid solution can be 1 mol:0.05-2.5 L, and can also be 1 mol:1-2.5 L, and can be specifically 1 mol:0.05 L, 1 mol:0.1 L, 1 mol:0.5 L, 1 mol:1 L, 1 mol:1.5 L, 1 mol:2 L or 1 mol:2.5 L.

[0034] In the application, the temperature of the recrystallization can be 0-100℃, and can also be 20-50℃, and can be specifically 0℃, 10℃, 20℃, 25℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃; the time of the recrystallization can be 1 min-48 h, and can also be 2-20 h, and can be specifically 1 min, 0.5 h, 1 h, 2 h, 5 h, 8 h, 10 h, 15 h, 20 h, 25 h, 30 h, 35 h, 40 h, 45 h or 48 h.

[0035] In the application, the preparation route of the perchlorate salt derivative of the pyrimidine self-coupling compound is as follows: .

[0036] The application further provides application of the pyrimidine self-coupling compound or the perchlorate salt derivative of the pyrimidine self-coupling compound in explosives.

[0037] In order to further illustrate the application, the application of the electrochemistry in the self-coupling of the pyrimidine compound under the condition of no catalyst, the pyrimidine self-coupling compound and the perchlorate salt derivative thereof, and the preparation method and application thereof are described in detail in the embodiments below, but they cannot be understood as limiting the protection scope of the application.

[0038] Example 1 2.2 Synthesis of 2,2',4,4',6,6'-hexamino-[5,5'-bipyrimidine] (HABP) Dissolve 2,4,6-triaminopyrimidine 20 mmol in 100 mL aqueous solution of triethylamine, use niobium tungsten oxide (chemical formula Nb 18 W 16 O 93 ) electrode as anode, platinum electrode as cathode, react at 90℃, 5V battery voltage for 48h, concentrate the obtained electrolyte and filter, sequentially wash the obtained solid component with water and ethanol, dry at 100℃ until constant weight to obtain HABP, 1.4g, yield 55%. Among them, the molar ratio of 2,4,6-triaminopyrimidine to triethylamine is 1:10.

[0039] 1 H NMR (400 MHz, D2SO4, 25℃): δ: 7.23(8H, NH2), 8.05(4H, NH2) ppm; 13 CNMR (100 MHz, D2SO4, 25℃): δ: 69.78, 149.54, 154.31 ppm; IR (KBr, cm -1 ):3491, 3465, 3349, 3184, 1607, 1557, 1478, 1429, 1016, 972, 801, 569, 555.HRMS (APCI - , m / z) calculated value C8H 11 N 10 - 247.1174, found 247.1175.

[0040] Example 2 2.2 Synthesis of 2,2',4,4',6,6'-hexamino-[5,5'-bipyrimidine] (HABP) Dissolve 2,4,6-triaminopyrimidine 20 mmol in 100 mL aqueous solution of potassium carbonate, use silicon / carbon (Si / C, Si content is 25wt%) electrode as anode, nickel electrode as cathode, react at room temperature, 1V battery voltage for 18h, concentrate the obtained electrolyte and filter, sequentially wash the obtained solid component with water and ethanol, dry at 50℃ until constant weight to obtain HABP, 1.275g, yield 50%. Among them, the molar ratio of 2,4,6-triaminopyrimidine to potassium carbonate is 1:1.

[0041] Example 3 Synthesis of 2,2',4,4',6,6'-hexaamino-[5,5'-bipyrimidine]-1,1',3,3'-tetraium perchlorate (HABPTP) HABP 2 mmol was recrystallized with 5 mL 90 wt% perchloric acid solution to obtain 1.36 g colorless transparent crystal HABPTP·2H2O with a yield of 99%. HABPTP·2H2O was heated under vacuum at 110 °C to constant weight to obtain anhydrous HABPTP.

[0042] 13 C NMR (100 MHz, D2O, 25 °C): δ: 72.37, 152.75, 157.41 ppm; IR (KBr, cm -1 ): 3313, 3107, 2820, 2728, 1716, 1623, 1526, 1412, 1087, 763, 754, 627, 539, 507.

[0043] Example 4 HABP 2 mmol was recrystallized with 5 mL 70 wt% perchloric acid solution to obtain 1.34 g colorless transparent crystal HABPTP·2H2O with a yield of 97%. HABPTP·2H2O was heated under vacuum at 110 °C to constant weight to obtain anhydrous HABPTP.

[0044] Example 5 Synthesis of 2,2',4,4',6,6'-hexaamino-[5,5'-bipyrimidine]-1,1',3,3'-tetraium perchlorate (HABPTP) HABP 2 mmol was recrystallized with 5 mL 50 wt% perchloric acid solution to obtain 0.76 g colorless transparent crystal HABPTP·2H2O with a yield of 55%. HABPTP·2H2O was heated under vacuum at 110 °C to constant weight to obtain anhydrous HABPTP.

[0045] Example 6 Synthesis of 2,2',4,4',6,6'-hexaamino-[5,5'-bipyrimidine]-1,1',3,3'-tetraium perchlorate (HABPTP) HABP 2 mmol was recrystallized with 5 mL 20 wt% perchloric acid solution to obtain 0.4 g colorless transparent crystal HABPTP·2H2O with a yield of 29%. HABPTP·2H2O was heated under vacuum at 110 °C to constant weight to obtain anhydrous HABPTP.

[0046] Test Example 1 Performance test of HABPTP (anhydrous) prepared by the present application.

[0047] P: density measured at room temperature using a gas pycnometer; T d : onset decomposition temperature; ΔH f : calculated heat of formation; D v : calculated detonation velocity by EXPLO5 / 6.02; P: calculated detonation pressure by EXPLO5 / 6.02; IS: impact sensitivity; FS: friction sensitivity.

[0048] The results of comparison of the energy and physicochemical properties of HABPTP and cyclotrimethylene trinitramine (RDX, "hexogen") are shown in Table 1.

[0049] Table 1 Comparison of the energy and physicochemical properties of HABPTP and RDX

[0050] Note: RDX data from the literature (Tang Y, Huang W, Imler GH, Parrish DA, Shreeve JM. Enforced Planar FOX-7-like Molecules: A Strategy for Thermally Stable and Insensitive π-Conjugated Energetic Materials. J Am Chem Soc. 2020; 142(15):7153-7160.) As can be seen from Table 1, the HABPTP provided by the present application has high density, high thermal decomposition temperature, high heat of formation, high detonation velocity, high detonation pressure and low friction sensitivity, and exhibits excellent energetic performance, and the comprehensive performance is superior to that of hexogen, indicating that the HABPTP provided by the present application can be used as a high-energy explosive.

[0051] Test Example 2 The crystallographic data and CCDC number of HABPTP·2H2O are shown in Table 2 and Figure 1 , wherein the red ball is the oxygen element, the green ball is the chlorine element, the blue ball is the nitrogen element, the gray ball is the carbon element, and the white ball is the hydrogen element.

[0052] Table 2 Crystallographic data and structure refinement of HABPTP·2H2O

[0053] X-ray single crystal diffraction analysis shows that HABPTP crystallizes in the form of a hydrate (HABPTP·2H2O) and belongs to the monoclinic system The space group contains four molecules per unit cell (Z=4). The single crystal density calculated at 170 K is 1.865 g / cm³. 3 The asymmetric unit contains two HABPTP molecules and four water molecules. For example... Figure 1 As shown in Figure a, the crystal contains abundant NH…O hydrogen bonds (1.794~2.413 Å). These extensive hydrogen bond interactions promote the molecular assembly of HABPTP·2H2O, while the extended hydrogen bond network contributes to the high thermal stability of HABPTP. Figure 1 As shown in Figure b, due to the strong steric hindrance between the pyrimidine rings, the two pyrimidine rings in the crystal structure are nearly perpendicularly aligned, with a dihedral angle of 84.89°. The supercell structure of HABPTP·2H2O shows that water molecules are distributed around the HABPTP compound array, acting as both proton acceptors and donors. Figure 1 (c)

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Application of electrochemistry in self-coupling of pyrimidine compounds without catalyst.

2. Use according to claim 1, characterized in that, The pyrimidine compounds include 2,4,6-triaminopyrimidine.

3. A pyrimidine self-coupling compound having a structure shown in formula I: Formula I.

4. A preparation method of the pyrimidine self-coupling compound of claim 3, comprising the following steps: mixing 2,4,6-triaminopyrimidine, a basic reagent and a solvent, and performing electrochemical C-C bond coupling reaction to obtain the pyrimidine self-coupling compound.

5. The preparation method according to claim 4, characterized in that, The molar ratio of the 2,4,6-triaminopyrimidine and the basic reagent is 1:0.5-100; The basic reagent includes inorganic basic reagent and / or organic basic reagent; The solvent is water and / or organic solvent, and the organic solvent includes acetonitrile and / or alcohol solvent.

6. The production method according to claim 4 or 5, characterized by, The conditions of the electrochemical C-C bond coupling reaction include: the anode includes one or more of graphite, tungsten oxide, silicon-based material and tin-based material; the cathode includes one or more of platinum, graphite, carbon cloth and nickel foam; the temperature is 0-100℃; the voltage is 0.1-5V; and the time is 1-48h.

7. A perchlorate derivative of the pyrimidine self-coupling compound having a structure shown in formula II: Formula II.

8. A preparation method of the perchlorate derivative of the pyrimidine self-coupling compound of claim 7, comprising the following steps: re-crystallizing the pyrimidine self-coupling compound of claim 1 in a perchloric acid solution to obtain the perchlorate derivative of the pyrimidine self-coupling compound.

9. The production method according to claim 8, characterized by, The mass concentration of the perchloric acid solution is 20-90%; The ratio of the amount of substance of the pyrimidine self-coupling compound to the volume of the perchloric acid solution is 1 mol:0.05-2.5L; The temperature of the re-crystallization is 0-100℃, and the time is 1min-48h.

10. Application of the pyrimidine self-coupling compound of claim 3 or the perchlorate derivative of the pyrimidine self-coupling compound of claim 7 in explosives, solid propellant adjuvants or combustion catalysts.

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