Picryl derivatives of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one

Treatment of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one ( 1 ) with picryl fluoride (PkF) in 1-methyl-2-pyrrolidinone (NMP) gave a mixture of a monopicryl and a dipicryl derivative of 1 in a ratio of 2 :1 , respectively, regardless of the initial concentrations of 1 and PkF. The products were identified as 5-nitro-2-picryl-2,4-dihydro-3H-1,2,4-triazol-3-one ( 2 ) by X-ray crystallography and 5-nitro-2,4-dipicryl-2,4-dihydro-3H-1,2,4-triazol-3-one ( 4 ) by ¹⁵N labeling experiments.     

Density functional theory investigation on the degradation mechanisms of 3-nitro-1,2,4-triazol-5-one (NTO) in water

Structural Chemistry - The degradation mechanisms of 3-nitro-1,2,4-triazol-5-one (NTO) in the bulk water were explored at the density functional theory (DFT) level using the M06-2X functional and...     

Charge transport in polyaniline doped with 3-nitro-1,2,4-triazol-5(4H)-one

Polyaniline (PANI) base was protonated in aqueous solutions of an organic acid, 3-nitro-1,2,4-triazol-5(4H)-one (NTO). The temperature dependence of DC conductivity of PANI-NTO seems to correspond to the theory of variable range hopping (VRH) in three dimensions. The frequency dependence of AC conductivity also reflects the hopping nature of mobile charges. The activation energy for the polymers with protonation degree above 0.12 remains constant with increasing dopant concentration and DC conductivity. The value of this constant may correspond to the energy needed for the ionization of dopant counterion. The fit of the electric relaxation function to the stretched exponential function ϕ(t) = exp[−(t/τ)^β] gives the stretch parameter β about 0.35, which shows that the distribution of relaxation times is broad and indicates a high inhomogeneity in the distribution of a dopant.     

3-Nitro-1,2,4-triazol-5-one derivatives

3-Nitro-1,2,4-triazol-5-one and its monomethyl derivatives react with methyl vinyl ketone to give products of addition to the ring N₁ and N₄ atoms. The reaction with formaldehyde and N-methylolacetamide proceeds only at the N₁ atom. The keto derivatives of 3-nitro-1,2,4-triazol-5-one undergo the Schmidt reaction to give the corresponding acetamides. A number of compounds that include functional groups in the N₁-alkyl substituent of the 3-nitro ring were obtained by treatment of the bases of N₁-substituted 3,5-dinitro-1,2,4-triazoles in aprotic media.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 552–558, April, 1981.     

Studies on the synthesis and thermal decomposition mechanisms of rare-earth metal (Pr,Nd, Sm) salt hydrates of 3-nitro-1,2,4-triazol-5-one

Three new rare-earth metal (Pr, Nd and Sm) salt hydrates of 3-nitro-1,2,4-triazol-5-one (NTO) were prepared and characterized. The thermal behaviour of the three salt hydrates, M(NTO)₃·nH₂O (M=Pr and Nd,n=9;M=Sm,n=8) were studied by means of TG and DSC under conditions of linear temperature increase. The thermal decomposition intermediates were determined by means of IR, MS and X-ray diffraction spectrometry. The thermal decomposition mechanisms of these hydrates were proposed as follows: We express our thanks to Professor Zhu Chunhua, Associate Professor Fu Xiayun, and Lecturers Fan Tao and Liang Yanjun for their help in this work.     

A density-functional theory investigation of 3-nitro-1,2,4-triazole-5-one dimers and crystal

Density-functional method with different basis sets was applied to the study of the highly efficient and low sensitive explosive 3-nitro-1,2,4-triazole-5-one (NTO) in both gaseous dimer and its bulk state. The binding energies have been corrected for the basis set superposition errors. Six stable dimers (II-VII) were located. The corrected binding energy of the most stable dimer VII is predicted to be -53.66 kJ/mol at the B3LYP/6-311++G(**) level. It was found that the structures of the more stable dimers (V-VII) are through the hydrogen bonding interaction between the carbonyl oxygen and the azole hydrogen of 3-nitro-1,2,4-triazole-5-one. The changes of Gibbs free energies (DeltaG) in the processes from the monomer to the dimers at 298.15 K are 8.51, 0.90, 0.35, -8.74, -10.67, and -11.06 kJ/mol for dimers from II to VII, respectively. Dimers V-VII, possessing cyclic structures, can be spontaneously produced from the isolated monomer at room temperature. The lattice energy is -156.14 kJ/mol, and this value becomes to -150.43 kJ/mol when a 50% correction of the basis set superposition error was adopted. The frontier bands are quite flat. Judged from the value of band gap of 4.0 eV, it may be predicted that 3-nitro-1,2,4-triazole-5-one is an insulator. Most atoms in NTO, with the exception of C(5) atom and the nitro atoms, make up the upper valence bands. In contrast, the lower conduction bands mainly consist of the nitro N and O atoms. The population of the C-NO(2) bond is much less than those of the other bonds and the detonation may be initiated by the breakdown of this bond.     

Non-isothermal Kinetics of the Thermal Decomposition of 3-Nitro-1,2,4-triazol-5-one Magnesium Complex

Introduction3 Nitro 1,2 ,4 triazol 5 one (NTO)metalcomplexeshavemanyspecialstructuresandsomepotentialusesinammunition .1 4 Wepreviouslypreparedanddeterminedthecrystalstructureofitsmagnesiumcomplex ,5andinthispaper ,wediscusseditsthermalbehaviorbyDSCandTG/DTGtechniquesandstudieditsnon isothermalkineticsbythemeansoftheKissingermethod ,theOzawamethod ,thedifferentialmethodandtheintegralmethod .ExperimentalSample[Mg(H2 O) 6 ](NTO) 2 ·2H2 Owaspreparedasfollows :AcalculatedamountofMg(OH…     

Synthesis and pancreatic lipase inhibitory activities of some 1,2,4-triazol-5(3)-one derivatives

In this study, starting from 4-amino-5-(4-chlorobenzyl)-2,4-dihydro-3H-1,2,4-triazole-3-one ( 1 ), the 4-Amino-5-(4-chlorobenzyl)-2-undecyl-2,4-dihydro-3H-1,2,4-triazol-3-one ( 2 ) was first synthesized and this compound was converted to Schiff base derivatives ( 3a-e ). In the second step of the study, the 2-[3-(4-chlorobenzyl)-5-oxo-1-undecyl-1,5-dihydro-4H-1,2,4-triazole-4-yl]-acetohydrazide ( 6 ), which was used as a key product in the synthesis of many heterocyclic compounds was synthesized in four steps, and then this compound was converted into methylidene acetohydrazide ( 7a-e ), thiosemicarbazide ( 8a-e ), and 1,2,4-triazole-5-thione ( 9a-e ) derivatives. Also, in the last part of the study, 1,2,4-triazole-5-thione derivatives were changed into Mannich bases ( 10a-b ) bearing a 4-phenylpiperazine ring. These new compounds were tested with regard to pancreatic lipase (PL) inhibition activity, and compound 3b , 3d , 7d , 8d , and 9d showed a considerable anti-lipase activity at various concentrations. The activity of compounds 7b (IC₅₀ = 1.45 ± 0.12 μM) was the highest in terms of IC₅₀, comparable to that of orlistat, a well-known PL inhibitor used as an antiobesity drug.     

Application of ab initio molecular dynamics for a priori elucidation of the mechanism in unimolecular decomposition: the case of 5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one (NTO).

We have tested a new and general approach for the theoretical study of unimolecular decomposition. By combining the power of the ab initio molecular dynamics (MD) and ab initio molecular orbital (MO) methods, our approach requires no prior experimental knowledge or intuitive assumptions about the decomposition. Instead, the reaction channels are first sampled theoretically by simulating a molecule at high temperature in a number of trajectories, using the density functional theory (DFT) based ab initio MD method with a planewave basis set and pseudopotentials. Each type of these channels is then further examined by well-established ab initio MO method to locate the energy barrier and transition structure and to verify the ab initio MD results. The power of such an approach is demonstrated in a case study for the complicated unimolecular thermal decomposition of NTO (5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one), with several interesting new features uncovered. The C-NO2 homolysis is indeed the dominant channel at high temperature, while the departing NO2 could capture a H atom from the NTO ring to form HONO, by either a concerted bond breaking mechanism or by a bimolecular reaction between the NO2 group and the triazol ring. At lower temperature, the dissociation channels initiated by hydrogen migrations should be activated first. The channel with hydrogen migration followed by ring opening and then by HONO loss has an energy barrier of 38.0 kcal/mol at the rate-determining step, being the lowest among all the investigated dissociation paths and much lower than previously thought. The energy barrier for nitro-nitrite rearrangement is lower than that for the C-NO2 homolysis but makes only a minor contribution due to the entropy factor. And the NTO ring could rupture in the two C-N bonds connected to the carbonyl carbon, and the energy barriers for such processes are only 2-4 kcal/mol higher than that for the C-NO2 homolysis.     

Non-isothermal decomposition kinetics,thermal behavior and computational detonation properties on 4-amino-1,2,4-triazol-5-one (ATO)

The thermal behavior of 4-amino-1,2,4-triazol-5-one (ATO) was studied under non-isothermal condition by DSC method in a sealed cell of stainless steel. The melting enthalpy and melting entropy of ATO are 21.34 ± 0.49 kJ mol⁻¹ and 46.54 ± 0.30 J mol⁻¹ K⁻¹, respectively. The kinetic parameters were obtained from the analysis of DSC curves by Kissinger method, Ozawa method, the differential method and the integral method. The main exothermic decomposition reaction mechanism of ATO is classified as nucleation and growth, and the kinetic parameters of the reaction are E_a = 119.50 kJ mol⁻¹ and A = 10^9.03 s⁻¹. The gas products and condensed phase products of the thermal decomposition of ATO were studied on two simultaneous devices of the fast thermolysis reaction cell (gas reaction cell) in situ in conjunction with rapid scan transform infrared spectroscopy (RSFT-IR) and the solid reaction cell in situ. The heat of formation (HOF) for ATO was evaluated by G3 theory. The detonation velocity (D) and detonation pressure (P) were estimated by using the well-known Kamlet–Jacobs equation, based on the theoretical HOF and the determined crystal density.     

Solvatochromism of Heteroaromatic Compounds: XII. Solvatochromism and Tautomerism of 4-Methyl-3-nitro-1,2,4-triazol-5-one in Aprotic Solvents

The long-wave absorption band in the UV spectrum of 4-methyl-3-nitro-1,2,4-triazol-5-one is highly sensitive to specific solvation by hydrogen bonding with a protophilic solvent. The UV and IR spectra suggest that the compound mainly exists in the form of the N¹H tautomer. The qualitative and quantitative relationships characterizing the solvent effect on the spectral characteristics of the major tautomer were elucidated.     

Optimization of the synthesis of 5-amino-1,2,4-triazol-3-ylacetic acid and bis(5-amino-1,2,4-triazol-3-yl)methane

The influence of the molar ratio and concentration of the reactants and of the temperature and time of the synthesis on the yield of malonic acid guanylhydrazides in the reaction of aminoguanidine with malonic acid in acidic aqueous solutions was examined, and improved procedures for preparing 5-amino-1,2,4-triazol-3-ylacetic acid and bis(5-amino-1,2,4-triazol-3-yl)methane were suggested.     

Thermal decomposition properties of 1,2,4-triazole-3-one and guanidine nitrate mixtures

1,2,4-triazole-3-one (TO) and guanidine nitrate (GN) have the potential to be used as alternative gas-generating agents. To obtain a better understanding of thermal decomposition properties of TO/GN mixtures, sealed cell differential scanning calorimetry, thermogravimetry–differential thermal analysis–infrared spectroscopy (TG–DTA–IR), and thermogravimetry–differential thermal analysis–mass spectrometry (TG–DTA–MS) were carried out. The endothermic peak and onset temperatures of TO/GN mixtures were lower than those of individual TO and GN. TG–DTA–IR and TG–DTA–MS showed that the mass of TO/GN mixtures decreased with heat generation and N₂ evolved as the major gas during thermal decomposition. The interaction between TO and nitric acid from the dissociation of GN is proposed for the thermal decomposition of TO/GN mixtures.     

3-硝基-1,2,4-三唑-5-酮羟胺盐的合成及其晶体结构

3-硝基-1,2,4-三唑-5-酮(NTO)与氢氧化钠反应得到NTO钠盐,再与盐酸羟胺反应合成了NTO的羟胺盐(HANTO),其结构经13CNMR,IR,MS,元素分析和四园单晶X-射线射衍仪表征。结果表明:HANTO属三斜晶系,空间群为P-1,晶胞参数为:a=0.6625(2)nm,b=0.7124(4)nm,c=0.7221(3)nm,α=68.46(4)°,β=71.36(3)°,γ=67.50(3)°,V=0.2864(2)nm3,Dc=1.891g.cm-3,Z=2,F(000)=168,μ(MoKα)=0.177mm-1。最终偏离因子R=0.0533,wR=0.1404。HANTO分子中存在分子内和分子间氢键。     

Thermal Decomposition of Ammonium 3-Nitro-1,2,4-triazol-5-onate Monohydrate

The thermal decomposition of ammonium 3-nitro-1,2,4-triazol-5-onate monohydrate[NH4（NTO）·H2O] was studied by means of thermal analysis-MS coupling and the combination technique of in situ thermolysis cell with rapid-scan Fourier transform infrared spectroscopy. The results show that there are two endothermic steps and one exothermic step in the decomposition process of NH4（NTO）·H2O. The detected gas products consist of NH3, H2O, N2, CO2, CO, and NO2.     

NTO二聚体分子间相互作用的理论研究

在DFT-B3LYP/6-311＋＋G**水平上求得NTO二聚体势能面上六种优化构型和电子结构. 经基组叠加误差(BSSE)和零点能(ZPE)校正, 求得分子间最大相互作用能为－53.66 kJ/mol. 二子体系间的电荷转移很少. 由自然键轨道分析揭示了相互作用的本质. 对优化构型进行振动分析, 并基于统计热力学求得200.0～800.0 K温度范围从单体形成二聚体的热力学性质变化. 发现二聚主要由强氢键所贡献, 但结合能大小并不为氢键所完全决定. 二聚过程在较低温度或常温下能自发进行.