RU2817968C1 - 3-(5-nitratomethyl-1h-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole derivatives and method for production thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions relates to organic chemistry, specifically to 4-amino-3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-1,2,5-oxadiazole derivative of general formula I, where R¹=CH₂OH, and to a method for production thereof.

EFFECT: disclosed is 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole derivative of formula I as a component of energy-intensive plasticisers of mixed solid rocket fuels.

4 cl, 1 tbl, 2 ex

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, derivatives of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro -1,2,5-oxadiazole general structural formula:

where R=H (Ia) or CH ₂ ONO ₂ (Ib), and the method of their preparation.

Compounds of general formula I can find application as energy-intensive plasticizers for mixed solid rocket fuels (SRP) and other energy condensed systems.

A structurally similar 3-methyl-4-nitrofurazan is described in the literature (according to the SciFinder CAS American Chemical Society database) with the formula:

(Yu.M. Lotmentsev, N.N. Kondakova, A.V. Bakeshko, A.M. Kozeev, A.B. Sheremetev, “3-Alkyl-4-nitrofurazans - plasticizers for polymers”, Chem. Heterocycl. Compd., 2017, 53, 740-745).

Compound II is characterized by increased volatility and a low oxidant excess coefficient, which makes its use ineffective as an energy-intensive plasticizer for STRT and other energy condensed systems.

A structurally similar 4-nitro-3-(5-amino-1,2,4-oxadiazol-3-yl)furazan is also known (according to the SciFinder CAS American Chemical Society database) with the formula:

(Q. Wang, Y. Shao, M. Lu, "C ₈ N ₁₂ O ₈ : A Promising Insensitive High-Energy-Density Material", Cryst. Growth Des., 2018, 18, 6150-6154). Compound III is characterized by low thermal stability and a relatively low oxygen balance, which makes its use ineffective as an energy-intensive plasticizer for STRT and other energy condensed systems. The literature also describes the energy-intensive compound 3-nitratoethyl-N-nitramino-5-nitratomethylisoxazole with the structural formula:

(G.E. Cabrera, T.A. Reid, E.S. Johnson, J.A. Orlicki, N.Z. Burns, J.J. Sabatini, "Synthesis and Characterization of the Potential Energetic Propellant Plasticizer 3-Nitratoethyl-N-nitramino-5-nitratomethyl Isoxazole, ChemPlusChem, 2022, 87, e202200096).

Compound IV is characterized by low thermal stability and a negative enthalpy of formation, which makes its use ineffective as an energy-intensive SPT plasticizer.

The technical objective of the present invention is to find new compounds of a series of nitro-1,2,5-oxadiazoles containing a nitratomethyl-1,2,3-triazole fragment and characterized by a combination of a high onset temperature of intensive decomposition above 160°C, a positive enthalpy of formation (ΔH° _f >120 kcal/kg), moderate density (ρ>1.40 g/cm ³ ), high total nitrogen and oxygen content ([N+O]>75%) and optimal oxidant excess ratio (α>0.5), which will ensure the effectiveness of their use as energy-intensive plasticizers for STRT and other energy condensed systems, as well as the development of a method for their production.

The stated technical problem is achieved by new, not described in the literature, derivatives of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole with the general structural formula:

where R=H (Ia) or CH ₂ ONO ₂ (Ib), and the method of their preparation.

The proposed compounds of general formula I contain one or two explosophoric nitratomethyl groups, which allows increasing the density (ρ=1.43-1.49 g/cm ³ ), the total content of nitrogen and oxygen ([N+O]>75% ) and the coefficient of excess oxidant (α>0.50), and the presence of a thermostable aromatic 1,2,3-triazole ring in compounds I ensures their acceptable temperature for the onset of intensive decomposition (>160°C) and a high positive enthalpy of formation (ΔH° _f >120 kcal/kg). Compounds of general formula I can find application as energy-intensive plasticizers for STP and other energy-intensive condensed systems.

A method has also been proposed for the preparation of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole derivatives of general formula I, where R=H (Ia) or CH ₂ ONO ₂ (Ib), consisting in the fact that the derivative of 4-amino-3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-1,2,5-oxadiazole of the general formula:

where R ¹ =H or CH ₂ OH, is subjected to oxidation with concentrated hydrogen peroxide in the presence of concentrated sulfuric acid, resulting in derivatives 3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro -1,2,5-oxadiazole of the general formula:

where R ¹ has the above values, is subjected to interaction with a nitrating reagent, followed by isolation of the target product. The process of obtaining the target product Ia proceeds according to the following scheme 1:

The process of obtaining the target product Ib proceeds according to the following scheme 2:

Highly concentrated hydrogen peroxide is used as an oxidizing agent at stage 1 of the preparation of 3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (VI) derivatives (80-90%) in the presence of high concentration sulfuric acid (95-98%). The process is carried out at temperatures from 0 to 25°C, preferably at 15°C. For example, a mixture of anhydrous nitric acid with high concentration sulfuric acid (95-98%). The process is carried out at temperatures from 0 to 20°C.

The table presents the physicochemical and energetic characteristics of 3-(5-nitratomethyl-1P-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole derivatives (I) in comparison with known compounds (II-IV) and with the standard energy-intensive plasticizer STRT BuNENA (n-butylnitroxylnitramine).

Compounds Ia and Ib in terms of enthalpy of formation (ΔH° _f ), density (ρ), oxidant excess coefficient (α) and total content of nitrogen and oxygen ([N+O]) are significantly superior to such a standard energy-intensive plasticizer as n-butylnitroxyethylnitramine (BuNENA ) (see table). Also, compounds Ia and Ib in terms of the temperature at which intensive decomposition begins and the total content of nitrogen and oxygen ([N+O]) are significantly superior to the known energy-intensive compounds II-IV (see Table). The technical result of the present invention is the creation of energy-intensive derivatives of a new type of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole of general formula I, where R= H (Ia) or CH ₂ ONO ₂ (Ib), and development of a method for their production. Compounds Ia and Ib have high densities (ρ = 1.43 and 1.49 g/cm ³ , respectively), high total nitrogen and oxygen contents ([N+O] = 75.5 and 77.0%, respectively), optimal values of the oxidant excess coefficient (α=0.52 and 0.64, respectively), acceptable temperatures for the onset of intensive decomposition (167 and 161°C, respectively) and high positive enthalpies of formation (ΔH° _f =296 and 130 kcal/kg, respectively). Thanks to this combination of characteristics, derivatives of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (Ia and Ib) may be of interest as energy-intensive plasticizers SRT and other energy condensed systems.

The starting derivatives of 4-amino-3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-1,2,5-oxadiazole Va and Vb were obtained from 3-azido-4-aminofurazan and propargyl alcohol or 1,4-butynediol according to a published method (LV Batog, L.S. Konstantinova, V.Yu. Rozhkov, Yu.A. Strelenko, O.V. Lebedev and L.I. Khmel'nitskii, Synthesis of 4-R-3-(4- R ¹ -5-R ² -1,2,3-triazol-1-yl)furazans. 1. Azidofurazans in 1,3-dipolar cycloaddition reactions with substituted acetylenes, Chem. Compd., 2000, 36, 91- 100).

The invention is illustrated by the following examples, which do not limit its scope.

Example 1. Preparation of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (Ia).

Step 1. Preparation of 3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (VIa).

To a mixture of 85% aqueous hydrogen peroxide (6 ml) and 98% aqueous sulfuric acid (6 ml) at 15°C, 4-amino-3-(5-hydroxymethyl-1H-1,2,3-triazol- 1-yl)-1,2,5-oxadiazole (1.09 g, 6 mmol). The reaction mass was stirred at 18-20°C for 2.5 hours, then poured into crushed ice (30 g) and extracted with ethyl acetate (3×15 ml). The combined organic extracts were washed with cold distilled water (3×20 ml) and dried over MgSO ₄ . The desiccant was filtered off, the solvent was distilled off in vacuo, and the resulting residue was purified by column chromatography on SiO ₂ (eluent CHCl ₃ -EtOAc, 3:1). 0.76 g (61%) of 3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole was obtained as a light yellow oil. High resolution mass spectrum (ESI): Found: m/z: 213.0365 [M+H] ⁺ . _{C5H5N6O4 . ​ ​} Calculated: m/z: 213.0367 [M+H] ⁺ . IR spectrum (thin layer), ν/cm ^-1 : 3359, 2934, 1603, 1565, 1513, 1513, 1353, 1304, 1256, 1230, 1087, 1033, 978, 886, 824, 745. NMR spectrum ^1H (DMSO- _d6 , δ, ppm, 300 MHz): 4.78 (s, 2H, _CH2 ), 5.93 (br.s, 1H, OH), 8.01 (s, 1H, CH). ^13C NMR spectrum (DMSO- _d6 , δ, ppm, 75.5 MHz): 53.7 ( _CH2 ), 132.6 (C(5) triazole ring), 142.2 (C(3) furazan ring), 145.9 ( C(4) triazol cycle), 156.5 (C(4) furazan cycle). Elemental analysis for C ₅ H ₄ N ₆ O ₄ (%): Found: C, 28.14; N, 2.07; N, 39.38. _{C5H4N6O4 . ​ ​} Calculated: C, 28.31; N, 1.90; N, 39.62.

Step 2. Preparation of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (Ia).

A solution of 3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (0.91 g, 4 mmol) in dry MeCN (2.5 ml) was added dropwise to a stirred mixture of 100% HNO ₃ (4 ml) and 98% H ₂ SO ₄ (4 ml) at 0-5°C (ice cooling). At the end of the dropwise addition, the cooling bath was removed and the reaction mass was stirred at 15-20°C for 1.5 hours, then poured into crushed ice (30 g) and extracted with CH ₂ Cl ₂ (3×15 ml). The combined organic extracts were washed with cold distilled water (3×20 ml) and dried over MgSO ₄ . The desiccant was filtered off, the solvent was distilled off in vacuo, and the resulting residue was purified by column chromatography on SiO ₂ (eluent CHCl ₃ -EtOAc, 2:1). 0.82 g (80%) of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole was obtained as a light yellow oil. The yield in two stages was 49%. DSC (5°C/min): dec. 167°C. High resolution mass spectrum (ESI): Found: m/z: 280.0032 [M+Na] ⁺ . _{C5H3N7NaO6 . ​ ​} Calculated: m/z: 280.0037 C ₅ H ₃ N ₇ NaO ₆ [M+Na] ⁺ . ^1H NMR spectrum ( _CDCl3 , δ, ppm, 300 MHz): 5.82 (s, 2H, _CH2 ), 8.05 (s, 1H, CH). ^13C NMR spectrum ( _CDCl3 , δ, ppm, 75.5 MHz): 60.6 ( _CH2 ), 132.0 (C(5) triazole ring), 136.6 (C(3) furazan ring), 143.2 (C( 4) triazole cycle), 154.0 (C(4) furazan cycle). ¹⁴ N NMR spectrum (CDCl ₃ , δ, ppm, 21.7 MHz): -50.3 (ONO ₂ ), -40.5 (NO ₂ ). Elemental analysis for C ₅ H ₃ N ₇ O ₆ (%): Found: C, 23.53; N, 1.06; N, 37.85. _{C5H3N7O6 . ​ ​} Calculated: C, 23.36; N, 1.18; N, 38.13.

Example 2. Preparation of 3-(4,5-dinitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (Ib).

Step 1. Preparation of 3-(4,5-dihydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (VIb).

4-amino-3-(4,5-dihydroxymethyl-1H-1,2,3- triazol-1-yl)-1,2,5-oxadiazole (1.27 g, 6 mmol). The reaction mass was stirred at 18-20°C for 2.5 hours, then poured into crushed ice (30 g) and extracted with ethyl acetate (3×15 ml). The combined organic extracts were washed with cold distilled water (3×20 ml) and dried over MgSO ₄ . The desiccant was filtered off, the solvent was distilled off in vacuo, and the resulting residue was purified by column chromatography on SiO ₂ (eluent CHCl ₃ -EtOAc, 3:1). 0.97 g (67%) of 3-(4,5-dihydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole was obtained in the form of light white crystals , m.p. 112-113°C. High resolution mass spectrum (ESI): Found: m/z: 243.0470 [M+H] ⁺ . _{C6H7N6O5 . ​ ​} Calculated: m/z: 243.0472 C ₆ H ₇ N ₆ O ₅ [M+H] ⁺ . IR spectrum (KBr), ν/cm ^-1 : 3419, 3359, 1610, 1563, 1520, 1426, 1381, 1312, 1258, 1221, 1113, 1054, 1020, 1001, 824, 790. NMR spectrum ¹ H ( DMSO-d ₆ , δ, ppm, 300 MHz): 4.65 (s, 2H, CH ₂ ), 4.82 (s, 2H, CH ₂ ), 5.30 (br. s, 1H, OH), 5.90 (br. s, 1H, OH). ^13C NMR spectrum (DMSO- _d6 , δ, ppm, 75.5 MHz): 53.5 ( _CH2 ), 54.4 ( _CH2 ), 138.6 (C(5) triazole ring), 144.9 (C(3) furazan . cycle), 146.3 (C(4) triazole cycle), 156.6 (C(4) furazan cycle). Elemental analysis for C ₆ H ₆ K ₆ O ₅ (%): Found: C, 29.54; N, 2.62; N, 34.42. _{C6H6N6O5 . ​ ​} Calculated: C, 29.76; N, 2.50; N, 34.71.

Step 2. Preparation of 3-(4,5-dinitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (Ib).

A solution of 3-(4,5-dihydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole (0.97 g, 4 mmol) in dry MeCN (2 .5 ml) was added dropwise to a stirred mixture of 100% HNO ₃ (4 ml) and 98% H ₂ SO ₄ (4 ml) at 0-5°C (ice cooling). At the end of the dropwise addition, the cooling bath was removed and the reaction mass was stirred at 15-20°C for 1.5 hours, then poured into crushed ice (30 g) and extracted with CH ₂ Cl ₂ (3×15 ml). The combined organic extracts were washed with cold distilled water (3×20 ml) and dried over MgSO ₄ . The desiccant was filtered off, the solvent was distilled off in vacuo, and the resulting residue was purified by column chromatography on SiO ₂ (eluent CHCl ₃ -EtOAc, 2:1). 0.65 g (49%) of 3-(4,5-dinitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole was obtained as a light yellow oil . The yield in two stages was 33%. DSC (5°C/min): dec. 161°C. High resolution mass spectrum (ESI): Found: m/z: 333.0171 [M+H] ⁺ . _{C6H5N8O9 ,. ​ ​} Calculated: m/z: 333.0174 C ₆ H ₅ N ₈ O ₉ [M+H] ⁺ . ^1H NMR spectrum ( _CDCl3 , δ, ppm, 300 MHz): 5.77 (s, 2H, _CH2 ), 5.87 (s, 2H, _CH2 ). ^13C NMR spectrum ( _CDCl3 , δ, ppm, 75.5 MHz): 59.8 ( _CH2 ), 63.7 ( _CH2 ), 131.9 (C(5) triazole ring), 141.7 (C(3) furazan ring ), 143.1 (C(4) triazole ring), 154.2 (C(4) furazan ring). ¹⁴ N NMR spectrum (CDCl ₃ , δ, ppm, 21.7 MHz): -50.8 (ONO ₂ ), -47.7 (NO ₂ ). Elemental analysis for C ₆ H ₄ N ₈ O ₉ (%): Found: C, 21.94; N, 1.07; N, 33.46. _{C6H4N8O9 . ​ ​} Calculated: C, 21.70; N, 1.21; N, 33.74.

Claims (10)

1. 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole derivative of general formula I: where R= CH ₂ ONO ₂ . 2. Derivative of 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole of general formula I according to claim 1 as a component of energy-intensive mixed solid plasticizers rocket fuels (SRT). 3. A method for preparing the 3-(5-nitratomethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole derivative of general formula I according to claim 1, consisting in the oxidation of concentrated hydrogen peroxide in the presence of concentrated sulfuric acid of the 4-amino-3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-1,2,5-oxadiazole derivative of general formula V: where R ¹ = CH ₂ OH, with the formation of a 3-(5-hydroxymethyl-1H-1,2,3-triazol-1-yl)-4-nitro-1,2,5-oxadiazole derivative of general formula VI: where R ¹ has the above value, which is subjected to interaction with a nitrating reagent, followed by isolation of the target product. 4. The production method according to claim 3, characterized in that a mixture of anhydrous nitric acid and concentrated sulfuric acid is used as a nitrating agent.