Synthesis and thermal decomposition behavior of nitrogen- and oxygen-rich energetic material N-trinitromethyl-4,5-dicyano-2H-1,2,3-triazole

N-trinitromethyl-4,5-dicyano-2H-1,2,3-triazole was readily synthesized from 4,5-dicyano-2H-1,2,3-triazole. Its crystal structure was obtained for the first time and its crystalline density in 296 K was 1.729 g cm⁻³. It shows high nitrogen and oxygen content up to 77.6%, high calculated solid heat of formation (564 kJ mol⁻¹), and superior detonation pressure and detonation velocity (D = 8619 m s⁻¹, P = 30.8 GPa). This new hydrogen-absent explosive shows high impact and friction sensitivities (IS: 1.25 J, FS: 32 N), which is lower than commercial primary explosive 2-diazonium-4,6-dinitrophenol (DDNP) (IS: 1 J, FS: 5 N). The relationship between intermolecular interaction and sensitivity as well as thermal stability of the title compound was investigated by Hirshfeld surface analysis and fingerprint plot. Its thermodynamic properties were studied by non-isothermal kinetic methods based on the results of differential scanning calorimeter. It is interesting that apparent activation energy (E_a) at T_p1 (210.89–214.17 kJ mol⁻¹) is higher than those at T_p2 (133.90–134.87 kJ mol⁻¹). In addition, gaseous product of this new energetic compound was analyzed by the rapid scanning Fourier transform infrared spectroscopy from 20 to 200 °C and its detonation products was theoretically predicted. Based on the decomposition products, its decomposition mechanism was discussed under inert atmosphere. It is undoubted that these significant physicochemical properties make N-trinitromethyl-4,5-dicyano-2H-1,2,3-triazole a potential hydrogen-absent primary explosive.

     

Metal salts of the 4,5-dicyano-2H-1,2,3-triazole anion ([C4N5]-)

Diaminomaleodinitrile was reacted at low temperatures with in situ generated nitrous acid to form 4,5-dicyano-2H-1,2,3-triazole (1) in yields above 90%. Crystalline 1 was then reacted with one equivalent of a suitable alkali or alkaline earth metal base (typically a hydroxide or a carbonate) in a polar solvent to form the corresponding alkali and alkaline earth metal salts of 4,5-dicyano-2H-1,2,3-triazole (compounds 2-9). The thermal stability of the metal salts 2-9 was assessed by differential scanning calorimetry, which showed excellent thermal stabilities up to above 350 °C. Due to the energetic character of triazole-based salts, initial safety testing was used to assess the sensitivity of compounds 2-9 towards impact, friction, electrostatic discharge and fast heating. These results revealed very low sensitivities towards all four stimuli. Additionally, compounds 2-9 were characterized by mass spectrometry, elemental analysis, infrared and Raman spectroscopy and ((1)H, (13)C and (14)N) NMR spectroscopy. We also determined the solid state structure of the 4,5-dicyano-2H-1,2,3-triazole anion of one of the alkali metal salts (4: Monoclinic, P2(1)/c, a = 9.389(1) ?, b = 10.603(1) ?, c = 6.924(1) ?, β = 102.75(1)° and V = 1036.58(3) ?(3)) and one of the alkaline earth metal salts (6: Monoclinic, P2(1)/c, a = 9.243(1) ?, b = 15.828(2) ?, c = 6.463(1) ?, β = 90.23(1)° and V = 945.5(2) ?(3)). Furthermore, we noted the hydrolysis of one of the cyano groups of the 4,5-dicyano-2H-1,2,3-triazole anion in the strontium salt 8 to form the 5-cyano-2H-1,2,3-triazole-4-carboxylic acid derivative 8b, as confirmed by X-ray studies (8b: Monoclinic, P2(1)/n, a = 6.950(1) ?, b = 17.769(1) ?, c = 13.858(1) ?, β = 92.98(1)° and V = 1709.1(1) ?(3)). Lastly, we computed the NBO and Mülliken charges for the anion of compounds 2-9 and those of the anion of compound 8b.     

Synthesis of 2-amino-4,5-disubstituted 3,5-dicyano-4,5-dihydrofurans

A new reaction was found for the preparation of difficult-to-obtain polyfunctional dihydrofurans, viz., the reaction of tetracyanoethylated ketones with hydrogen peroxide in the presence of a base.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1027–1030, August, 1985.     

Ion chemistry of 1H-1,2,3-triazole

A combination of experimental methods, photoelectron-imaging spectroscopy, flowing afterglow-photoelectron spectroscopy and the flowing afterglow-selected ion flow tube technique, and electronic structure calculations at the B3LYP/6-311++G(d,p) level of density functional theory (DFT) have been employed to study the mechanism of the reaction of the hydroxide ion (HO-) with 1H-1,2,3-triazole. Four different product ion species have been identified experimentally, and the DFT calculations suggest that deprotonation by HO- at all sites of the triazole takes place to yield these products. Deprotonation of 1H-1,2,3-triazole at the N1-H site gives the major product ion, the 1,2,3-triazolide ion. The 335 nm photoelectron-imaging spectrum of the ion has been measured. The electron affinity (EA) of the 1,2,3-triazolyl radical has been determined to be 3.447 +/- 0.004 eV. This EA and the gas-phase acidity of 2H-1,2,3-triazole are combined in a negative ion thermochemical cycle to determine the N-H bond dissociation energy of 2H-1,2,3-triazole to be 112.2 +/- 0.6 kcal mol-1. The 363.8 nm photoelectron spectroscopic measurements have identified the other three product ions. Deprotonation of 1H-1,2,3-triazole at the C5 position initiates fragmentation of the ring structure to yield a minor product, the ketenimine anion. Another minor product, the iminodiazomethyl anion, is generated by deprotonation of 1H-1,2,3-triazole at the C4 position, followed by N1-N2 bond fission. Formation of the other minor product, the 2H-1,2,3-triazol-4-ide ion, can be rationalized by initial deprotonation of 1H-1,2,3-triazole at the N1-H site and subsequent proton exchanges within the ion-molecule complex. The EA of the 2H-1,2,3-triazol-4-yl radical is 1.865 +/- 0.004 eV.     

Photo- and thermal elimination of nitrogen from 4-phenyl- and 4,5-diphenyl-1,2,3-triazole

Phenylacetonitrile ( 2 ) (32%) and small amounts of benzyl methyl ether ( 3 ), benzonitrile ( 5 ) and methyl benzoate ( 6 ) were produced by irradiation of either 4-phenyl-1,2,3-triazole ( 1 ) or 4-phenyl-5-deutero-1,2,3-triazole ( 7 ) in methanol at 254 nm. In methylene chloride, irradiation of 1 produced 2 (15%) and small amounts of 3,6-diphenyl-1,2,4,5-tetrazine ( 8 ). Irradiation of 4,5-diphenyl-1,2,3-triazole ( 9 ) in methanol gave 2,4,5-triphenylimidazole ( 11 ) (4%) and trace amounts of diphenylacetonitrile ( 10 ), benzamide ( 12 ), and compounds 3 , 5 , and 6 . Irradiation of 2,3-diphenyl-2H-azirine ( 13 ) in methanol gave small amounts of 3 , benzaldehyde ( 4 ), and compounds 5 , 6 , 12 as well as 2,3,5,6-tetraphenylpyrazine ( 14 ) and in methylene chloride it gave 11 (16%) and small amounts of 4 , 5 , 14 , and acetophenone ( 15 ). On heating 4-phenyl-1,2,3-triazole ( 1 ) in n-hexadecane, elimination of nitrogen at 290° left phenylacetonitrile ( 2 ) as the only identified product. Similar pyrolysis of 4,5-diphenyl-1,2,3-triazole ( 9 ) produced 2,3,5,6-tetraphenylpyrazine ( 14 ) along with an intractable material. An efficient thermal isomerization of 2,3-diphenyl-2H-azirine ( 13 ) gave 2-phenylindole ( 17 ).     

Conversion of α-azoxyoximes to 2H-1,2,3-triazole N-oxide derivatives

Reaction of the syn isomers of -hydroxylaminooximes with nitrobenzene gives -azoxy-oximes, which undergo intramolecular cyclization to 2H-1,2,3-triazole N-oxide derivatives under the influence of hydrogen chloride.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 131–133, January, 1973.     

2-甲基-4,5-二硝基三唑-1-氧化物的合成及其结构表征

以乙二醛、甲基肼和盐酸羟胺为起始原料,经缩合、肟化得到中间体肟基甲腙;该中间体不经分离直接加入到硫酸铜-吡啶-水体系中,经缩合环化得到2-甲基三唑-1-氧化物(MTO);随后用混酸(硝酸+硫酸)硝化得到目标产物2-甲基-4,5-二硝基三唑-1-氧化物(DNMTO);初步探讨了环化反应的机理,研究了反应温度与时间等因素对硝化反应的影响,确定了最佳硝化反应条件.与此同时,利用红外光谱、核磁共振、质谱及元素分析等分析了中间产物和DNMTO的组成和结构.结果表明,目标产物的总收率为16%,纯度为99%;最佳硝化反应温度为100℃,最佳硝化反应时间为0.5h.     

Synthesis of 3-substituted 4-imino-4,5-dihydro-1,2,3-triazole 1-oxides and 4-amino-1,2,3-triazole 1-oxides. Crystal and molecular structure of 4-imino-5,5-dimethyl-3-phenyl-4,5-dihydro-1,2,3-triazole 1-oxide

A new procedure for the synthesis of triazole N-oxides, based on base-induced intramolecular cyclization of 1-(-cyanoalkyl)-3-aryl(hetaryl)triazen-1-oxides, is proposed. An X-ray study of 4-imino-5,5-dimethyl-3-phenyl-4,5-dihydro-1,2,3-triazole 1-oxide was carried out.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 746–751, April, 1993.     

Synthesis of N-Vinyl-1,2,3-triazole Derivatives

Nitro-substituted N-vinyl-1,2,3-triazole derivatives were synthesized by the vinyl exchange reaction. The process was promoted by the catalytic system mercury(II) acetate-trifluoroacetic acid. This system is universal, and it can be used in the synthesis of vinylazoles having two, three, and four nitrogen atoms in the ring. in the ring.     

Functionalisation of 1,2,3-triazole via lithiation of 1-[2-(trimethylsilyl)ethoxy]methyl-1H-1,2,3-triazole

The preparation of a number of 5-substituted 1-[2-(trimethylsilyl)ethoxy]methyl-1H-1,2,3-triazoles via reaction of 1-[2-(trimethylsilyl)ethoxy]methyl-1H-1,2,3-triazole with n-butyllithium followed by addition of various electrophiles is reported. Removal of the protecting group by action of diluted aqueous hydrochloric acid or by tetrabutylammonium fluoride in tetrahydrofuran leads to the appropriate 4-substituted 1H-1,2,3-triazoles.     

Reactions of 2,4-Disubstituted 5-Nitro-1,2,3-triazole 1-Oxides. 4. Dealkylation of 2-Substituted 4,5-Dinitro-1,2,3-triazole 1-Oxides

The N-dealkylation of 2-alkyl or 2-benzyl-substituted 4,5-dinitro-1,2,3-triazole 1-oxides has been studied. Conditions have been found for N-de-tert-butylation and 4-amino-5-nitro-1,2,3-triazole 1-oxide has been synthesized for the first time.     

Diazoaldehyde Chemistry. Part 3. Synthesis of 4-acyl-1H-1,2,3-triazole derivatives

Ten new α-diazo-β-oxoaldehydes were condensed with aniline, ammonia, hydroxylamine, and semicarbazide to yield new 4-acyl-(1-substituted)-1H-1,2,3-triazoles in moderate-to-good yields. The method is simple and regiospecific. The latter feature makes this method superior to the widely used acylacetylene + azide approach.     

14N and 15N NMR Spectroscopy of 2-Methyl-4,5-dinitro-1,2,3-triazole and of Substituted 2-Methyl-4(5)-nitro-1,2,3-triazole 1-Oxides

Analysis of the ¹⁴N and ¹⁵N NMR spectroscopic data of 2-methyl-4,5-dinitro-1,2,3-triazole and of substituted 2-methyl-4(5)-nitro-1,2,3-triazole 1-oxides has shown the possibility of applying them for confirmation of the structures of the studied compounds.     

1,4-二取代-1,2,3-三唑衍生物的合成

在超声波辐射下,端基炔与叠氮基(3,3-二甲基-2,4-二氧戊环基)甲烷通过1,3-偶极环加成合成了1-(3,3-二甲基-2,4-二氧戊环基甲基)-4-芳基-1,2,3-三唑(5);5在酸性条件下脱保护得1-(2,3-二羟基丙基)-4-芳基-1,2,3-三唑,其结构经1H NMR,13C NMR,MS和元素分析表征。