RU2775006C1 - Substituted (cyano-nno-azoxy)furazans and method for their preparation - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to substituted (cyano-NNO-azoxy)furazans of general formula

where R = NH₂ (Ia),

or

. The invention also relates to a process for the preparation of said compounds.

EFFECT: compounds of a new type of (cyano-NNO-azoxy)furazans of general formula (I) have been obtained, which can be used as effective energy-intensive fillers for solid fuels for ramjet engines.

4 cl, 3 ex, 1 tbl

Description

The present invention relates to the field of organic chemistry, namely, to the chemistry of energy-intensive heterocyclic compounds, specifically, to new, not described in the literature, substituted (cyano-NNO-azoxy)furazans of the general formula:

где

where

или

и к способу их получения.R=NH ₂ (Ia),

or

and how to obtain them.

Compounds of general formula I can find application as energy-intensive fillers of solid fuels for ramjet engines (ramjet engines).

Two structurally similar (cyano-NNO-azoxy) compounds are described in the literature (according to the SciFinder CAS database of the American Chemical Society), with the general formula:

где

where

(S.G. Zlotin, N.V. Airapetova, E.A. Vinogradova, A.I. Podgursky, Yu.A. Strelenko, O.A. Lukyanov, "New regiospecific methods for the synthesis of N'-cyanodiazene N-oxides" N.A. Troitskaya-Markova, O.G. Vlasova, T.I. Godovikova, S.G. Zlotin, O.A. Rakitin, Mendeleev Communications, Izv. 2017, 27, 448-450).

A similar high-energy (cyano-NNO-azoxy) compound is also described in the literature (according to the SciFinder CAS American Chemical Society database), formulas:

(V.I. Pepekin, L.M. Kostikova and V.P. Lebedev, Proceedings of 36th International Annual Conference of ICT, Karlsruhe, Germany, 2005, p. 95).

The described structurally similar (cyano-NNO-azoxy)compound Na is not a high-energy compound, compound IIb is low-melting (mp 76-77°C) and is characterized by a relatively low enthalpy of formation, and compound III has an oxidizer excess coefficient (α) higher than the optimal value of α=0.2-0.4, which makes the use of these compounds as energy-intensive fillers of solid fuels for ramjet engines ineffective.

The technical objective of the present invention is to find new, not described in the literature, compounds of the series (cyano-NNO-azoxy)furazans, characterized by a combination of high enthalpy of formation, the optimal excess ratio of the oxidizing agent and a melting point above 90 ° C, as well as the development of a method for their preparation.

The set technical task is achieved by new substituted (cyano-NNO-azoxy)furazans of the general formula, not described in the literature:

где

where

или

R=NH ₂ (Ia),

or

and how to get them.

The proposed compounds of general formula I are high-energy substances containing in their molecule both a (cyano-NNO-azoxy) group and other explosophoric substituents, which ensures a high enthalpy of formation and an optimal oxygen balance of these compounds.

или

заключающийся в том, что N-(4-нитрозофуразан-3-ил)-2,2,2-трифторацетамид (IV) подвергают взаимодействию с цианамидом и дибромизоциануровой кислотой (ДБИ) в апротонном органическом растворителе, полученный при этом 2,2,2-трифторо-N-{4-(циано-NNO-азокси)фуразан-3-ил}ацетамид (V) обрабатывают кислотой в полярном протонном органическом растворителе в присутствии воды, образующийся при этом 3-амино-4-(циано-NNO-азокси)фуразан (Ia) выделяют, далее при необходимости получения 3,3-(E)-диазен-1,2-диил-бис[4-(циано-NNO-азокси)фуразана] (Iб), соединение Ia обрабатывают дибромизоциануровой кислотой в апротонном органическом растворителе, либо, при необходимости получения 3-амино-4-{[4-(циано-NNO-азокси)-фуразан-3-ил]-NNO-азокси}фуразана (Iв), соединение Ia подвергают взаимодействию с N-(4-нитрозофуразан-3-ил)-2,2,2-трифторацетамидом (IV) и дибромизоциануровой кислотой в среде апротонного органического растворителя, полученный при этом 2,2,2-трифторо-N-(4-{[4-(циано-NNO-азокси)фуразан-3-ил]-NNO-азокси}фуразан-3-ил)ацетамид (VI) обрабатывают кислотой в полярном протонном органическом растворителе в присутствии воды с последующим выделением 3-амино-4-{[4-(циано-NNO-азокси)фуразан-3-ил]-NNO-азокси}фуразана (Iв).Also proposed is a method for obtaining substituted (cyano-NNO-azoxy)furazans of general formula I, where R=NH ₂ (Ia),

or

consisting in the fact that N-(4-nitrosofurazan-3-yl)-2,2,2-trifluoroacetamide (IV) is subjected to interaction with cyanamide and dibromoisocyanuric acid (DBI) in an aprotic organic solvent, thus obtained 2,2,2 -trifluoro-N-{4-(cyano-NNO-azoxy)furazan-3-yl}acetamide (V) is treated with acid in a polar protic organic solvent in the presence of water, resulting in the formation of 3-amino-4-(cyano-NNO- azoxy)furazan (Ia) is isolated, then, if necessary, obtaining 3,3-(E)-diazene-1,2-diyl-bis[4-(cyano-NNO-azoxy)furazan] (Ib), compound Ia is treated with dibromoisocyanuric acid in an aprotic organic solvent, or, if it is necessary to obtain 3-amino-4-{[4-(cyano-NNO-azoxy)-furazan-3-yl]-NNO-azoxy}-furazan (Ic), compound Ia is subjected to interaction with N -(4-nitrosofurazan-3-yl)-2,2,2-trifluoroacetamide (IV) and dibromoisocyanuric acid in an aprotic organic solvent, the resulting 2,2,2-trifluoro-N-(4-{[4- (cyano-NNO-azoxy)furazan-3-yl]-NNO-azo xy}furazan-3-yl)acetamide (VI) is treated with acid in a polar protic organic solvent in the presence of water, followed by isolation of 3-amino-4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO -azoxy}furazan (Ic).

The processes for obtaining target products Ia, Ib and Ic proceed according to the following scheme:

As an aprotic organic solvent at the stage of obtaining 2,2,2-trifluoro-N-[4-(cyano-NNO-azoxy)furazan-3-yl]acetamide (V) use, for example, diethyl ether, methylene chloride. The process is carried out at a temperature from 0 to 25°C.

As a polar protic organic solvent at the stage of obtaining 3-amino-4-(cyano-NNO-azoxy)furazan (Ia), for example, methanol is used, and as an acid, for example, trifluoroacetic acid. The process is carried out at a temperature of -20 to 0°C.

As an aprotic organic solvent in the preparation of 3,3-(E)-diazene-1,2-diylbis[4-(cyano-NNO-azoxy)furazan] (Ib) use, for example, methylene chloride, acetonitrile. The process is carried out at a temperature from 0 to 25°C.

As an aprotic organic solvent at the stage of obtaining 2,2,2-trifluoro-N-(4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}furazan-3-yl)acetamide (VI) use, for example, acetonitrile, methylene chloride. The process is carried out at a temperature from 0 to 25°C. As a polar protic organic solvent in the preparation of 3-amino-4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}furazan (Ic), for example, methanol is used, and as an acid such as trifluoroacetic acid. The process is carried out at a temperature of -20 to 0°C.

A measure of the efficiency of energy-intensive fillers of solid fuels for ramjet engines (ramjet) is the lowest volumetric calorific value (Q _v(low) , MJ/l). The higher this value, the more effective the compound as an energy-intensive filler of solid fuels for ramjet engines. The value of the lower volumetric heat of combustion of an energy-intensive filler is directly affected by its enthalpy of formation, density and excess coefficient of the oxidizer (α) (M.E. Reznikov, "Aviation fuels and lubricants (aviation chemmotology)", Military publishing house, Moscow, 2004, p. 323; D. B. Lempert, V. V. Raznoschikov, L. S. Yanovsky, "Evaluation of the influence of the elemental composition, density and enthalpy of formation of solid propellant dispersants on the flight range of an atmospheric aircraft", Journal of Applied Chemistry, 2019, 92, 1578-1583).

The technical result of the present invention is the creation of compounds of a new type (cyano-NNO-azoxy)furazans of general formula I and the development of a method for their preparation. Compounds Ia-c have high experimental values of the enthalpy of formation (742-1073 kcal/kg), good density (1.69-1.75 g/cm ³ ) and optimal values of the oxidizer excess coefficient (α) in the range from 0.29 to 0.36 (Table). Due to this combination of characteristics, (cyano-NNO-azoxy)furazans Ia-b in terms of lower volumetric calorific value (Q _v(low) ) are significantly superior to octogen (NMX), the most efficient energy-intensive filler of solid fuels for ramjet engines among standard components.

Thus, compounds of general formula I, which have high values of the volumetric calorific value (19.85–21.09 MJ/l), may be of interest as efficient energy-intensive fillers of solid fuels for ramjet engines.

The starting N-(4-nitrosofurazan-3-yl)-2,2,2-trifluoroacetamide (IV) was obtained from 3-amino-4-nitrosofurazan according to the published method (N.E. Leonov, M.S. Klenov, O.V. Anikin , A.M. Churakov, Y.A. Strelenko, A.A. Voronin, D.B. Lempert, N.V. Muravyev, I.V. Fedyanin, S.E. Semenov, V.A. Tartakovsky, "Synthesis of New Energetic Materials Based on Furazan Rings and Nitro-NNO-azoxy Groups", ChemistrySelect, 2020, 5, 12243-12249).

The starting dibromoisocyanuric acid (DBI) was prepared from cyanuric acid according to a published method (W. Gottardi, "Reaction of bromine with alkali cyanurates", Monatsh. Chem., 1967, 98, 507-512).

The invention is illustrated by the following non-limiting examples.

Example 1

Stage 1. Preparation of 2,2,2-trifluoro-N-[4-(cyano-NNO-azoxy)furazan-3-yl]acetamide (V).

To a solution of N-(4-nitrosofurazan-3-yl)-2,2,2-trifluoroacetamide (IV) (2.0 g, 9.52 mmol) in dry CH ₂ Cl ₂ (60 ml) at 0°C and stirring was added in one portion DBI (2.7 g, 9.52 mmol) and then a solution of cyanamide (0.4 g, 9.52 mmol) in dry Et ₂ O (20 ml) was added dropwise over 5 min. The resulting suspension was heated to 25°C and stirred at this temperature for 24 hours. The precipitate of cyanuric acid was filtered off, washed with CH ₂ Cl ₂ (2×50 ml) and the filtrate was evaporated to dryness. The resulting crude 2,2,2-trifluoro-N-[4-(cyano-NNO-azoxy)furazan-3-yl]acetamide (V) was used in the next step without further purification.

Stage 2. Obtaining 3-amino-4-(cyano-NNO-azoxy)furazan (Ia).

=50 Гц), -118 (N(O)=N-CN,

=880 Гц), -336 (NH₂,

=800 Гц). Спектр ЯМР ¹⁵N (ацетон-d₆, δ, м.д., 60.83 МГц): 35.0, 2.3 (атомы азота фуразанового цикла), -42.3 (N(O)=N-CN), -99.4 (N(O)=N-CN), -117.6 (N(O)=N-CN), -335.6 (NH₂). Пример 2. Получение 3,3-(E)-диазен-1,2-диилбис[4-(циано-NNO-азокси)-фуразана] (Iб).2,2,2-Trifluoro-N-[4-(cyano-NNO-azoxy)furazan-3-yl]acetamide (V) obtained in step 1 was dissolved in MeOH (16 ml), then water (6 ml) was added ) and trifluoroacetic acid (0.2 ml) and kept the reaction mixture at -20°C for 24 h. Then the reaction mixture was concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluent - petroleum ether-AcOEt (5:1)). The product fractions were combined and concentrated in vacuo at 35° C. to a volume of ~50 ml. The precipitate was filtered off, washed with cold hexane (2×25 ml) and dried in vacuo. 0.98 g (67%) of 3-amino-4-(cyano-NNO-azoxy)furazan (Ia) was obtained in the form of yellow crystals. DSC (5°C.min ^-1 ): T _pl. \u003d 117 ° С, T _{n. decomp.} =209°С. Elemental analysis for C ₃ H ₂ N ₆ O ₂ : Found: H, 1.35; C, 23.41; N, 54.44. C ₃ H ₂ N ₆ O ₂ . Calculated: H, 1.31; C, 23.38; N, 54.54. High Resolution Mass Spectrum (ESI): Found: m/z: 260.9288 [M+Ag] ⁺ . C ₃ H ₂ N ₆ O ₂ . Calculated: m/z: 260.9285 [M+Ag] ⁺ . IR spectrum (KBr), ν/cm ^-1 : 3463 s, 3361 s, 3211 w, 3158 w, 2208 w, 1635 s, 1584 m, 1500 m, 1453 s, 1420 m, 1359 s, 1218 m. 1H NMR spectrum (acetone-d ₆ , δ, ^ppm , 600.13 MHz): 6.65 (br. s, 2H, NH ₂ ). ^13С NMR spectrum (acetone-d ₆ , δ, ppm, 150.90 MHz): 109.8 (CN), 152.0 (br. s, С(4)), 152.1 (С(3)). ¹⁴ N NMR spectrum (acetone-d ₆ , δ, ppm, 43.37 MHz): -43 ( N (O)=N-CN,

=50 Hz), -118 (N(O)=NC N ,

\u003d 880 Hz), -336 (NH ₂ ,

=800 Hz). ¹⁵ N NMR spectrum (acetone-d ₆ , δ, ppm, 60.83 MHz): 35.0, 2.3 (nitrogen atoms of the furazan ring), -42.3 ( N (O)=N-CN), -99.4 (N (O )= N -CN), -117.6 (N(O)=NC N ), -335.6 (NH ₂ ). Example 2 Preparation of 3,3-(E)-diazene-1,2-diylbis[4-(cyano-NNO-azoxy)-furazan] (Ib).

=1000 Гц), -49 (N(O)=N-CN,

=40 Гц), -114 (N(O)=N-CN,

=750 Гц). Спектр ЯМР ¹⁵N (ацетон-d₆, δ, м.д., 60.83 МГц): 145.5 (N=N), 40.7, 34.7 (атомы азота фуразанового цикла), -48.7 (N(O)=N-CN), -87.2 (N(O)=N-CN), -112.3 (N(O)=N-CN).Finely ground _{DBI powder} ( 8.71 g, 30.37 mmol). The reaction mixture was stirred at 25°C for 24 hours the Precipitate was filtered off, washed with CH ₂ Cl ₂ (4×50 ml) and the filtrate was evaporated to dryness. The residue was purified by column chromatography on silica gel (eluent - petroleum ether-AcOEt (5:1)). 1.61 g (70%) of 3,3-(E)-diazene-1,2-diylbis[4-(cyano-NNO-azoxy)furazan] (Ib) was obtained in the form of orange crystals. DSC (5°C.min ^-1 ): T _pl. \u003d 90 ° С, T _{n. decomp.} =222°С. Elemental analysis for C ₆ N ₁₂ O ₄ : Found: C, 23.71; N, 55.15. C ₆ N ₁₂ O ₄ . Calculated: C, 23.69; N, 55.26. High Resolution Mass Spectrum (ESI): Found: m/z: 327.0060 [M+Na] ⁺ . C ₆ N ₁₂ O ₄ . Calculated: m/z: 327.0058 [M+Na] ⁺ . IR spectrum (KBr), ν/cm ^-1 : 2203 w, 1559 w, 1492 s, 1419 w, 1333 w, 1198 m. ^13С NMR spectrum (acetone-d ₆ , δ, ppm, 125.76 MHz): 109.5 (CN), 155.2 (br. s, С(4) and С(4')), 157.9 (С(3) and C(3')). ¹⁴ N NMR spectrum (acetone-d ₆ , δ, ppm, 43.37 MHz): 147 (N=N,

\u003d 1000 Hz), -49 ( N (O) \u003d N-CN,

=40 Hz), -114 (N(O)=NC N ,

=750 Hz). ¹⁵ N NMR spectrum (acetone-d ₆ , δ, ppm, 60.83 MHz): 145.5 (N=N), 40.7, 34.7 (nitrogen atoms of the furazan ring), -48.7 ( N (O)=N-CN) , -87.2 (N(O)= N -CN), -112.3 (N(O)=NC N ).

Example 3

Step 1. Preparation of 2,2,2-trifluoro-N-(4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}furazan-3-yl)acetamide (VI).

To a solution of N-(4-nitrosofurazan-3-yl)-2,2,2-trifluoroacetamide (IV) (5.5 g, 26.18 mmol) in a mixture of dry CH ₂ Cl ₂ (10 ml) and dry MeCN (10 ml) at 0°C and stirring, DBI (7.5 g, 26.18 mmol) was added in one portion, and then 3-amino-4-(cyano-NNO-azoxy)furazan (Ia) (2.0 g, 12.98 mmol) was added in small portions over 10 min . The resulting suspension was heated to 25°C and stirred at this temperature for 24 hours the Precipitate was filtered off, washed with CH ₂ Cl ₂ (3×50 ml) and the filtrate was evaporated to dryness. The resulting crude 2,2,2-trifluoro-N-(4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}furazan-3-yl)acetamide (VI) was used in the next step without further purification.

Stage 2. Preparation of 3-amino-4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}furazan (Ic).

=55 Гц), -59 (Fz-N(O)=N-Fz,

=75 Гц), -114 (N(O)=N-CN,

=900 Гц), -336 (NH₂,

=1200 Гц). Спектр ЯМР ¹⁵N (ацетон-d₆, δ, м.д., 60.83 МГц): 38.7, 35.7, 33.9, 1.4 (атомы азота фуразановых циклов), -47.1 (N(O)=N-CN), -58.8 (Fz-N(O)=N-Fz), -87.2, -89.4 (Fz-N(O)=N-Fz и N(O)=N-CN), -113.4 (N(O)=N-CN), -336.4 (NH₂).2,2,2-Trifluoro-N-(4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}-furazan-3-yl)acetamide (VI), obtained at the stage 1 was dissolved in MeOH (40 ml), then water (30 ml) and trifluoroacetic acid (1 ml) were added and the reaction mixture was kept at -20°C for 24 hours. The reaction mixture was then concentrated in vacuo. The residue was purified by column chromatography on silica gel (eluent - petroleum ether-AcOEt (5:1)). The product fractions were combined and concentrated in vacuo at 35° C. to a volume of ~50 ml. The precipitate was filtered off, washed with cold hexane (2×25 ml), dried in vacuo. 2.14 g (62%) of 3-amino-4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}furazan (Ic) was obtained in the form of yellow crystals. DSC (5°C.min ^-1 ): T _pl. \u003d 124 ° С, T _{n. decomp.} =193°C. Elemental analysis for C ₅ H ₂ N ₁₀ O ₄ : Found: H, 0.77; C, 22.61; N, 52.50. C ₅ H ₂ N ₁₀ O ₄ . Calculated: H, 0.76; C, 22.57; N, 52.63. High resolution mass spectrum (ESI): Found: m/z: 269.0488 [M+H] ⁺ . C ₅ H ₂ N ₁₀ O ₄ . Calculated: m/z: 260.0490 [M+H] ⁺ . IR spectrum (KBr), ν/cm ^-1 : 3467 s, 3336 s, 3251 w, 3187 w, 2203 w, 2191 w, 1630 s, 1564 w, 1541 m, 1507 s, 1489 s, 1451 m, 1430 Wed, 1402 Wed, 1357 Wed, 1330 Wed, 1221 Wed, 1169 Wed, 1109 Wed. 1Н NMR spectrum (acetone-d ₆ , δ, ^ppm , 600.13 MHz): 6.69 (br. s, 2Н, NH ₂ ). ^13С NMR spectrum (acetone-d ₆ , δ, ppm, 150.90 MHz): 109.7 (CN), 149.6 (С(3) or С(3')), 151.9 (С(3) or С(3 ')), 153.0 (br. s, C(4) or C(4')), 155.6 (br. s, C(4) or C(4')). ¹⁴ N NMR spectrum (acetone-d ₆ , δ, ppm, 43.37 MHz): -48 ( N (O)=N-CN,

\u003d 55 Hz), -59 (Fz- N (O) \u003d N-Fz,

=75 Hz), -114 (N(O)=NC N ,

\u003d 900 Hz), -336 (NH ₂ ,

=1200 Hz). ¹⁵ N NMR spectrum (acetone-d ₆ , δ, ppm, 60.83 MHz): 38.7, 35.7, 33.9, 1.4 (nitrogen atoms of furazan cycles), -47.1 ( N (O)=N-CN), -58.8 (Fz- N (O)=N-Fz), -87.2, -89.4 (Fz-N(O)= N -Fz and N(O)= N -CN), -113.4 (N(O)=NC N ), -336.4 (NH ₂ ).

Claims (7)

1. Substituted (cyano-NNO-azoxy)furazans of general formula (I)

where R \u003d NH ₂ (Ia),

or

. 2. Substituted (cyano-NNO-azoxy)furazans of general formula (I) according to claim 1 as energy-intensive fillers for solid fuels for ramjet engines. 3. A method for obtaining substituted (cyano-NNO-azoxy)furazans of general formula (I) according to claim 1, where R = NH ₂ (Ia),

, which consists in the fact that N-(4-nitrosofurazan-3-yl)-2,2,2-trifluoroacetamide (IV) is subjected to interaction with cyanamide and dibromoisocyanuric acid in an aprotic organic solvent, the resulting 2,2,2-trifluoro -N-{4-(cyano-NNO-azoxy)furazan-3-yl}acetamide (V) is treated with acid in a polar protic organic solvent in the presence of water, resulting in the formation of 3-amino-4-(cyano-NNO-azoxy) furazan (Ia) is isolated, then, if necessary, compound (Ia) is treated with dibromoisocyanuric acid in an aprotic organic solvent to obtain 3,3-(E)-diazen-1,2-di-ylbis[4-(cyano-NNO-azoxy)furazan ] (Ib). 4. A method for obtaining substituted (cyano-NNO-azoxy)furazans of general formula (I) according to claim 1, where R = NH ₂ (Ia),

, which consists in the fact that N-(4-nitrosofurazan-3-yl)-2,2,2-trifluoroacetamide (IV) is subjected to interaction with cyanamide and dibromoisocyanuric acid in an aprotic organic solvent, the resulting 2,2,2-trifluoro -N-{4-(cyano-NNO-azoxy)-furazan-3-yl}acetamide (V) is treated with acid in a polar protic organic solvent in the presence of water, resulting in the formation of 3-amino-4-(cyano-NNO-azoxy )furazan (Ia) is isolated, then, if necessary, compound (Ia) is reacted with N-(4-nitrosofurazan-3-yl)-2,2,2-trifluoroacetamide (IV) and dibromoisocyanuric acid in an aprotic organic solvent, obtained by 2,2,2-tri-fluoro-N-(4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}furazan-3-yl)acetamide (VI) is treated with acid in a polar protic organic solvent in the presence of water to obtain 3-amino-4-{[4-(cyano-NNO-azoxy)furazan-3-yl]-NNO-azoxy}furazan (Ic).