Facile synthesis of[1,2,4]triazino[4,3-b][1,2,4,5]tetrazepin derivatives by a one-pot reactions using 4-amino-3-hydrazinyl-6-methyl-1,2,4-triazin-5(4H)-one

4-Amino-3-mercapto-6-methyl-l,2,4-triazin-5（4H）-one 1 converted to 4-amino-6-methy-3-（methylthio）-1,2,4-triazin-5（4H）-one by methylation with methyl iodide.Controlled hydrazination of the resulting compound afforded 4-amino-3-hydrazinyl-6- methyl-l,2,4-triazin-5（4H）-one 2 as a building block,to the synthesis of some novel derivatives of[1,2,4]triazino- [4,3,b][1,2,4,5]tetrazepine 3-6,by the reaction with 3-chloropentane-2,4-dione,chloro acetonitrile,1,3-dichloroacetone,and methyl bromoacetate.This general synthetic procedure can be extended to the preparation of wide variety of tetrazepines using 1,2- bielectrophiles derivatives.

5-Nitro-1,2,4-triazole-3-one:A Review of Recent Advances

The 3?Nitro?1,2,4?triazole?5?one(NTO)is a high energy density materials of keen interest for both commercial and scientific worlds owing to its reduced sensitivity,better thermal stability and high performances. It plays a significant role to replace the current energetic ingredients. In this review,we summarize various strategies involved in the synthesis of NTO as well as the existing approaches to tailor its particle morphology and sizes. The most prominent properties of NTO,such as insensitivity and performance,which are usually required to produce efficient formulations,have been concisely discussed. In addition,this overview reports on some newer forms of NTO including derivatives and co?crystals available in the literature,which can enhance the NTO features and extend its applications. The advantages and shortcomings of various NTO forms for specific and potential use are also highlighted together with the attempts made to overcome these issues. Therefore,efforts will certainly continue to improve characteristics and performances of NTO either by chemical modification or by co?crystallization in order to produce promising formulations for widespread applications in the near future.

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.

Synthesis, Crystal Structure and Antitumor Activity of 2-(3-Methyl-5-(methylthio)-4H-1,2,4-triazol-4-yl)isoindoline-1,3-dione

The title compound 2-（3-methyl-5-（methylthio）-4H-1,2,4-triazol-4-yl）isoindoline- 1,3-dione （C12H10NaO2S, Mr= 274.30） has been synthesized by a three-step procedure including the cyclization, hydrazinolysis and substitution reactions, and its crystal structure was determined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P2/c with a = 12.264（3）, b = 14.646（3）, c = 14.349（4） A,β = 91.69（3）°,μ = 0.255 mm1, Mr = 274.30, V = 2576.2（10） A3, Z =8, Dc = 1.414 g/cm3, F（000） = 1136, R = 0.0487 and wR = 0.1329 for 4048 observed reflections with I 〉 2σ（I）. In addition, the preliminary bioassay suggested that the title compound 6 exhibits relatively good antitumor activity against HT-29 and MCF-7.

A new one-pot neat synthesis of 1,2,4-triazol-3-ones through 4-(N,N-dimethylamino) pyridine (DMAP) catalyzed cyclocondensation of ethyl carbazate with aryl nitriles

A new one-pot neat synthesis of some 5-aryl-2,4-dihydro-3H- 1,2,4-triazol-3-ones through cyclocondensation of ethyl carbazate with aryl nitriles catalyzed by DMAP as an efficient and basic nucleophilic catalyst is described.

Synthesis, Crystal Structure and Antitumor Activity of 4-tert-Butyl-N-(2-fluorophenyl)-5- (1H-1,2,4-triazol-1-yl)-thiazol-2-amine

The title compound has been synthesized by the reaction of 1-bromo-3,3-dime- thyl- 1 - （1 H- 1,2,4-triazol- 1 -yl）butan-2-one with 1 -（2-fluorophenyl）thiourea, and its crystal struc- ture was determined by single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbca with a = 15.2568（6）, b = 12.1533（5）, c = 16.7307（7） A, Z = 8, V = 3102.2（2） A3, Mr = 317.39, Dc = 1.359 g/cm3, S = 1.05, μ = 0.223 mm-1, F（000） = 1328, the final R = 0.034 and wR = 0.097 for 2590 observed reflections （I 〉 2σ（I））. X-ray crystal structure presents the intramolecular N-H…N hydrogen bond, which plays an important role in stabilizing the crystal structure. In addition, the preliminary biological test on the title compound shows good antitumor activity, with IC50 of 0.122 μmol/mL against the Hela cell line.

Synthesis, Crystal Structure and Antitumor Activity of 4-(tert-butyl)-5-(1H-1,2,4-triazol-1-yl)-N-(2-hydroxy-3,5-diiodinebenzyl)-thiazol-2-amine

The title compound, 4-（tert-butyl）-5-（1 H- 1,2,4-triazol- 1 -yl）-N-（2-hydroxy-3,5-diio- dinebenzyl）thiazol-2-amine, was synthesized via the reduction of 4-（tert-butyl）-5-（1H-l,2,4- triazol-l-yl）-N-benzylidene-thiazol-2-amine with NaBH4, and its crystal structure was determined by single-crystal X-ray diffraction. The compound crystallizes in monoclinic system, space group P21/c with a = 7.91944（19）, b = 10.5250（3）, c = 24.4985（6） A, Z = 4, V = 2041.66（9） A3, Mr = 599.22, Dc = 1,949 Mg/m3, S = 1.120, p = 3.203 mm-1, F（000） = 1152, the final R = 0.0283 and wR = 0.0592 for 3490 observed reflections （I 〉 2σ（I））. X-ray analysis displays that the crystal water takes part in three intermolecular hydrogen bonds of O（2）-H（2A）…O（1）, O（2）-H（2B）…N（I） and N（5）-H（5）…O（2）, and an octatomic ring R^（8） is formed via intramolecular hydrogen bond of O（I）-H（IA）…N（4）. Furthermore, the I…I contacts are involved in stabilizing the overall three-dimensional network structure. The preliminary biological test shows the title compound has good antitumor activity with the IC50 value of 26 μM against the Hela cell line.

Synthesis and Crystal Structure of 4-Salicyli deneamino-3-methyl-1,2,4-triazol-5-thione

The crystal structure of 4-salicylideneamino-3-methyl-1,2,4-triazol-5-thione 1 (C10H10N4OS, Mr = 234.28) has been determined by single-crystal X-ray diffraction method. The crystal belongs to monoclinic, space group P21/n with a = 12.697(3), b = 7.4072(15), c = 12.750(3) , b = 117.68(3), V = 1061.85(4) 3, Z = 4, Dc = 1.465 g/cm3, m = 0.288 mm-1 and F(000) = 488. R = 0.0584 and wR = 0.1642 for 2660 unique reflections with 2130 observed ones (I > 2s(I)). The results confirmed that the configuration of the title compound at the azomethine C=N bond is E and 1 can be assigned as the thione tautomeric form. All atoms of the title compound are essentially coplanar.

Synthesis,Crystal Structure and Antitumor Activity of(E)-N-(4-Fluorobenzylidene)-3-(methylthio)-5-(3,4,5-trimethoxyphenyl)-4H-1,2,4-triazol-4-amine

The crystal structure of the title compound（E）-N-（4-fluorobenzylidene）-3-（methylthio）-5-（3,4,5-trimethoxyphenyl）-4 H-1,2,4-triazol-4-amine（C_（19）H_（19）FN_4O_3S,Mr = 402.44） was synthesized,and its structure was characterized by 1 H-NMR,13 C-NMR,ESI-MS and single-crystal X-ray diffraction.The crystal belongs to the triclinic system,space group P1 with a = 9.228（13）,b = 10.364（14）,c = 10.641（14） ？,α = 85.323（3）,β = 75.172（2）,γ = 80.903（3）°,μ = 0.20 mm^（-1）,M_r = 402.44,V = 970.64（10） ？~3,Z = 2,D_c = 1.377 g/cm^3,F（000） = 420,R = 0.0484 and wR = 0.1474 for 3181 observed reflections with I 〉 2σ（I）.In addition,the preliminary bioassay indicated that the title compound 5 exhibits better inhibitory activity against Hela than 5-fluorouracil.

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

The thermal decomposition of 3-nitro-1,2,4-triazol-5-one magnesium complex and its kinetics were studied under the non-isothermal condition by DSC and TG/DTG methods. The kinetic parameters were obtained from analysis of the DSC and TG/DTG curves by the Kissinger method,the Ozawa method,the differential method and the integral method. The most probable mechanism functions for the thermal decomposition of the first stage,the second stage and the third stage were suggested by comparing the kinetic parameters. The entropy of activation (ΔS ≠),enthalpy of activation (ΔH ≠) and free energy of activation (ΔG ≠) at Tpdo are -66.74 J·mol -1 ·K -1 ,119.2 kJ·mol -1 and 152.44 kJ·mol -1 ,respectively.

Synthesis of N-Aryl-2-(1′,6′-dihydro-6′-pyridazinone-3′-carbonyl) Thiosemicarbazides and Their Related Heterocyclic Compounds

Dihydro-3-hydrozinocarbonyl-6-pyridazinone(compound 2) were prepared from α-ketoglutaric acid and hydrazine hydrate. A series of N-aryl-2-(1′,6′-dihydro-6′-pyridazinone-3′-carbonyl) thiosemicarbazides 3a_3f were synthesized from the reaction of aryl isothiocyanates with compound 2. The terminal compounds 1,3,4-thiadiazole, 1,3,4-oxadiazole and 1,2,4-triazol-5-thione derivatives were cyclized from compounds 3a_3f. Their structures were confirmed by IR, 1H NMR, MS and elemental analyses.

Three New Compounds Based on 4,4＇-Azo-l,2,4-triazol-5-one： Synthesis, Crystal Structure and Thermal Properties

A series of guanidine salts of 4,4＇-azo-l,2,4-triazol-5-one with guanidine（1）, aminoguanidine（2）, diaminoguanidine（3） and triaminoguanidine（4） was prepared. Compounds 2--4 were characterized by infrared（IR） spectroscopy, elemental analysis and single-crystal X-ray diffraction. Thermal decomposition processes of compounds 1--4 were investigated by differential scanning calorimetry（DSC）, and all the compounds showed good thermal stability up to 190 ℃. Moreover, these four guanidine salts are more unstable with the increasing number of amino groups. Thermal stability parameters（Te,0 and Tb）and thermodynamic functions（△S≠, △H≠ and △G≠） for compounds 1-4 were calculated. The constant-volume combustion heats（AcU） for compounds 2--4 were determined and tended to increase with the increase of the number of amino groups. The calculated standard molar enthalpies of forma- tion（△ρH0m） of compounds 2-4 are -541.04, -178.67 and-83.08 kJ/mol, respectively. The impact sensitivities results indicate that these four energetic salts are less sensitive than 1,3,5-trinitrotriazacyccohexane（RDX） and 1,3,5,7- tetranitrotetraqza-cyclo-octane（HMX）.

Synthesis, Crystal Structure and Antifungal Activity of a New Zn(Ⅱ) Complex Based on 4-(5-(Pyridin-3-yl)-4H-1,2,4-triazol-3-yl) Benzoic Acid

A new complex[Zn(3,4-APT)2(H2 O)4]·8 H2 O(1,3,4-HAPT=4-(5-(pyridin-3-yl)-4 H-1,2,4-triazol-3-yl)benzoic acid)has been prepared and characterized by elemental analysis,X-ray single-crystal diffraction analysis,thermogravimetric analysis and infrared spectrum analysis.Theoretical calculation based on density functional theory(DFT)is also employed to explicate frontier orbitals of 3,4-HAPT.X-ray single-crystal diffraction analysis reveals that 1 belongs to the triclinic system,space group P1 with a=7.5123(3),b=8.6745(3),c=15.2074(6)Å,α=78.469(1),β=87.387(1),γ=65.448(1)°,V=882.42(6)Å,Z=1,D_(c)=1.528 g·cm^(–3),μ=0.780 mm^(–1),M_(r)=812.09,F(000)=424,the final R=0.0401 and wR=0.1136.Zn(II)ion is coordinated by two N atoms from two 3,4-HAPT as well as four O atoms from four coordinated water molecules,forming a 0D motif with distorted octahedral coordinated geometry.The adjacent 0 D units are linked into a 3 D supramolecular structure through hydrogen bonding interaction.In addition,complex 1 exhibits better antifungal activity against Colletotrichum gloeosporioides Penz than the ligand and metal salt by MIC,MBC tests and Kirby-Bauer disc diffusion method which exhibit potential application in the antifungal fields.

Molecular Design and Property Prediction of High Density 4-Nitro-5-(5-nitro-1,2,4-triazol-3-yl)-2H-1,2,3-triazolate Derivatives as the Potential High Energy Explosives

To search for potential energetic materials with large energy density and acceptable thermodynamics and kinetics stability,twelve derivatives of 4-nitro-5-(5-nitro-1,2,4-triazol-3-yl)-2H-1,2,3-triazolate(named A~L)are designed and analyzed by using density functional theory(DFT)calculations at the B3LYP/6-311G**level of theory.The molecular heats of formation(HOF),electronic structures,impact sensitivity(H_(50)),oxygen balance(OB)and density(ρ)are investigated by isodesmic reaction method and physicochemical formulas.Furthermore,the detonation velocity(D)and detonation pressure(P)are calculated to study the detonation performance by Kamlet-Jacobs(K-J)equation.These results show that new molecule J(H_(50)=36.9 cm,ρ=1.90g/cm^(3),Q=1912.46 cal/g,P=37.82 GPa,D=9.22 km/s,OB=0.00),compound A(H_(50)=27.9 cm,ρ=1.93 g/cm^(3),Q=1612.93 cal/g,P=38.90 GPa,D=9.19 km/s)and compound H(H_(50)=37.3 cm,ρ=1.97 g/cm^(3),Q=1505.06cal/g,P=37.20 GPa,D=9.01 km/s)present promising effects that are far better RDX and HMX as the high energy density materials.Our calculations can provide useful information for the molecular synthesis of novel high energy density materials.

Theoretical Study on the Nitrogen-rich Derivatives Based on 1,2,4-Triazole and 1,2,3-Triazole Rings:an Extended Family of Power Performance Energetic Materials

The geometric and electronic structures of the derivatives of 4-nitro-5-(5-nitroimino-1,2,4-triazol-3-yl)-2H-1,2,3-triazolate(named A~J)are explored employing density functional theory(DFT)calculations at the B3LYP/6-311G^(**)level of theory.Based on the optimized molecular structures,the heats of formation(HOF)are obtained,and the electronic properties,density and molecular sensitivity by characteristic heights(H_(50))are discussed.Besides,the detonation performances(detonation velocity,detonation pressure)are estimated via Kamlet-Jacobs(K-J)formula.Compounds B(H50=29.4 cm,ρ=1.91 g/cm^(3),Q=1563.04 cal/g,P=36.05 GPa,D=8.95 km/s)and H(H_(50)=31.9 cm,ρ=1.80 g/cm^(3),Q=1610.09 cal/g,P=37.31 GPa,D=9.12 km/s)have positive HOFs and remarkable insensitivity and good detonation performance,strongly suggesting them as the acceptable new-type explosive.The initiating power surpasses conventional primary explosives,such as HMX.The outstanding detonation power of compounds B and H contributes to its future prospects as a promising green primary explosive.

The Thermal Decomposition Mechanism and the Quantum Chemical Calculation of[Mg（H2O）6]（NTO）2·2H2O

[Mg(H2O)6](NTO)2·2H2O Was prepared by adding magnesium carbonate hydroxide to the aqueous solution of 3-nitro-1，2，4-triazol-5-one(NTO)．Its thermal decomposition mechanism was studied by DSC，TG／DTGand IR．The quantum chemical calculation on the title complex as a structure unit with the experimental geometry as atartmg values was carried out at B3LYP level with 6-31G basis set．The results show that the bonds between the coordinate waters and the Mgatom have certain extent covalent character．The net charges on nitrogen atoms of the NTO ring appear to be negative while the nitrogen atom on the nitro group(—NO2)appears to be positive which indicates—NO2 will lost first when the complex is heated to some uniform temperature and this result is in agreement with that of the thermal decomposition experiment．

Preparation, Structural Characterization and Thermal Decomposition Mechanism of [Cu（TO）2（H2O）4]（PA）2

[Cu（TO）2（H2O）4]（PA）2 was prepared by the reaction of aqueous 1,2,4-triazol-5-one （TO） solution with the solution of copper picrate Cu（PA）2 and characterized by elemental analysis, FT IR and X-ray powder diffraction analysis. The title complex has been studied by means of TG-DTG and DSC under conditions of linear temperature increase. The thermal decomposition residues were examined by FT IR analysis. Thermal decomposition mechanism of the title complex was proposed. In the temperature range of 30-680 ℃, the thermal decomposition process was composed of four major stages. The first stage was an endothermic process with the loss of four coordination water molecules. Since the dehydration product was unstable, when it was heated, it would be decomposed much more easily. The second stage was composed of an acute endothermic process and a continued strong exothermic process and the main decomposed residues were CuCO3, Cu（NCO）2 and polymers during this stage. The third stage was a sharp exothermic process, which resulted from the decomposition of the polymer. After the forth stage, the final decomposed residues were certainly copper oxide. The Arrhenius parameters have been also studied on the dehydration process and the first-step exothermic decomposition of [Cu（TO）2（H2O）4]（PA）2 using Kissinger＇s method and Ozawa-Doyle＇s method. The results using both methods were consistent with each other. The Arrhenius equation can be expressed as in k=24.0-179.8 × 10^3/RT for the dehydration process and in k= 16.7-206.0 × 10^3/RT for the first-step exothermic decomposition, on the basis of the average of Ea and In A through the two methods.

Crystal structure and quantum chemical investigation of [Cd(NTO)_(4)Cd(H_(2)O)_(6)]·4H_(2)O

[Cd(NTO)4Cd(H2O)6] ?4H2O was synthesized by mixing the aqueous solution of 3-nitro-1, 2,4-triazol-5-one (NTO) and cadmium carbonate. The single crystal structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, space group C2/c with crystal parameters of a = 2.1229(3) nm, b = 0.6261(8) nm, = 2.1165(3) nm, β= 90.602 (3)°, V= 2.977(6) nm3, Z = 4, Dc = 2.055 g ? cm-3, μ = 15.45 cm-1 and F(000) = 1824. 2523 observable independent reflections with F04σ(F0) were used for the determination and refinement of the crystal structure. Lorentz-polarization and absorption correction were applied. The final R is 0.0282 and wR = 0.0792. The analytical results show that the Cd+2 has two kinds of coordinate bonds in one crystal. One Cd+2 coordinates with 4 NTO anions and another coordinates with 6 water molecules to form a binucleate complex with a structure of tetrahedron and tetragonal bipyramid, respectively. By using SCF-PM3-MO method, the electron structure of cadmium complex of NTO has been calculated. The analysis of the calculated results shows that when [Cd(NTO)4Cd(H2O)6] ? 4H2O is heated, the crystallization waters will be dissociated first and the ligand waters second and NO2 group has priority of leaving when NTO? is decomposed. Analysis of the energy level and composition of localized molecular orbitals indicates that both the two Cd2+ bond to the coordinating atom with 5s

Synthesis, Crystal Structure and Thermal Behavior of GZTO·H2O

Guanidimium-4,4-azo-l-hydro-1,2,4-triazol-5-one （GZTO·H2O） was synthesized from 4-amino-1,2,4-triazol- 5-one as a starting material by two-step including oxidation coupling using acid KMnO4 and reaction with （NH2）2C=NHoHNO3 （GN） in KOH solution. The single crystal of the title compound was obtained by slow evapo- ration method at room temperature, and its structure was firstly determined with X-ray single-crystal diffractometer. It is a orthorhombic crystal, space group Pbca with cell dimensions of a = 1.0459（2） nm, b =- 1.3584（3） nm, c= 1.6103（3） nm, a= 90.00（10）°, β=90.00（11）°,γ=90.00（11）°, V=2.2878（8） nm3, Z=8, De= 1.587 gocm-3, F（000） = 1136,/l = 0.132 mm- 1, R1 = 0.0455, wR2 = 0. 1397. The thermal behavior of GZTO·H2O was studied under a non-isothermal condition by DSC-TGA method, and its thermal decomposition process can be divided into three stages, and the first stage is an intense exothermic decomposition process. The second stage and the third stage are slow exothermic decomposition processes. The critical temperature of thermal explosion is 237.74℃.

The investigation of NTO/HMX-based plastic-bonded explosives and its safety performance

3-nitro-1,2,4-triazol-5-one(NTO)is the main component of insensitive munitions(IM)formulation because of its outstanding insensitive properties.In this paper,a series of NTO/HMX-based compositeexplosives were prepared and characterized.The study focuses on the effect of NTO on the perfommance of the formulations,especially the safety performance.The results revealed that the mechanical sensi-tivity of fomulations was associated with NTO content,as well as the thermal conductivity,specific heat capacity and Arrhenius parameters.Then,the high amount of NTO using in formulation was proved to be helpful for NTO/HMX-based formulation to exhibit good thermal safety.Besides,by accelerating rate calorimeter(ARC)and a modified cook-off equipment,the pressure and pressure rise rate were proved as the important indicator for judging the thermal safety performance in confined spaces.Finally,the numerical simulation was used as a credible method for predicting the respond temperature of cook-off experiment.