Theoretical Studies on Intermolecular Interactions of 4-Amino-5-nitro-1,2,3-triazole Dimers

Seven optimized configurations and their electronic structures of 4-amino-5-nitro- 1,2,3-triazole dimers on their potential energy surface have been obtained by using density functional theory （DPT） method at the B3LYP/6-311＋＋G＊＊ level. The maximum intermolecular interaction energy is -35.42 kJ/mol via the basis set superposition error-correction （BSSE） and zero point energy-correction （ZPE）. Charge transfers between the two subsystems are small. The vibration analysis of optimized configurations was performed, and the thermodynamic property changes from monomer to dimer have been obtained with the temperature ranging from 200 to 800 K on the basis of statistical thermodynamics. It is found that the hydrogen bonds contribute to the dimers dominantly, and the extent of intermolecular interaction is mainly determined by the hydrogen bonds＇ strength rather than their number. The dimerization processes of Ⅳ, Ⅴand Ⅵ can occur spontaneously at 200 K.

Synthesis and Crystal Structure of Ag_2(admtrz)_2(CF_3CO_2)_2(admtrz=4-amino-3,5-dimethyl-1,2,4-triazole)

The title compound (Ag2F6O4N8C12H16, Mr = 666.07) was synthesized and its crystal structure was determined by single-crystal X-ray diffraction method. It crystallizes in orthorhombic, space group Fddd with cell parameters: a = 12.2718(1), b = 23.3229(1), c = 29.1918(1) ? V = 8355.10(8) 3, Z = 16, Dc = 2.118 g/cm3, F(000) = 5184 and m = 1.966 mm-1. The structure was solved by direct methods and refined by full-matrix least-squares methods. The final R = 0.0624 and Rw = 0.1699 for 1584 observed reflections with I ≥ 2.0s(I). The molecular structure consists of two trigonal silver atoms bridged by double triazole ligands. The distance between the two silver atoms Ag(1)…Ag(1A) is 3.475(2) ?

Syntheses and Characterization of Two New Alkaline Earth Metal-organic Topological Frameworks with 3-Amino-1H-1,2,4-triazole-5-carboxylate

Two new alkaline earth metal coordination polymers constructed from the deriva-tive of 1,2,4-triazole are presented herein,namely,{[Sr（AmTAZAc）2（H2O）]}（1） and {[Ba（AmTAZAc）2（H2O）]}（2）（AmTAZAc = 3-amino-1H-1,2,4-triazole-5-carboxylate）,which have been synthesized by using the layering method and structurally characterized by elemental analysis,IR,and single-crystal X-ray diffraction.Complexes 1 and 2 are isostructural,and both crystallize in the orthorhombic system,space group Fdd2.X-ray structural analysis shows that 1 or 2 has an intriguing 3-D infinite network of（318.438.510） topology based on a 2-D sheet structure of（4,4） net.The result shows that noncovalent interactions play an important role in strengthening the whole structures of the compounds.

1-甲基-3-正丙基-4-氨基-5-吡唑羧酰胺的制备

1 甲基 3 正丙基 5 吡唑羧酸经硝酸 -浓硫酸硝化制得 1 甲基 3 正丙基 4 硝基 5 吡唑羧酸 ,收率 85 %;用氯化亚砜将其酰氯化制得 1 甲基 3 正丙基 4 硝基 5 吡唑羧酰氯 ,该吡唑羧酰氯与浓氨水反应制得 1 甲基 3 正丙基 4 硝基 5 吡唑羧酰胺 ,收率 90 %;硝基吡唑羧酰胺在乙醇中用氯化亚锡还原制得 1 甲基 3 正丙基 4 氨基 5 吡唑羧酰胺 ,收率 84%。研究了反应的较佳合成工艺条件 ,产品经TLC、IR及MS谱进行了结构表征。

Key Intermediates: A Simple and Highly Selective Synthesis of 5-<i>Amino</i>-1-<i>aryl</i>-1<i>H</i>-<i>pyrazole</i>-4-<i>carbonitriles</i>for Applications in the Crop Protection

A series of six pyrazoles was synthesized by Michael-type addition reaction. The molecules 5-amino-1-aryl-1H-pyrazole-4-carbonitrile (3a-f) were synthesized from (ethoxymethylene)malo-nonitrile (1) and fluorinated and non-fluorinated aryl hydrazines (2a-f) using ethanol and fluorinated ethanol as solvents at reflux. An excellent regio-selectivity was found when pyrazole derivatives were formed as an exclusive product. No other regioisomer or uncyclised hydrazide was observed. Their structures were confirmed by spectroscopy data (1H, 13C, 19F, COSY (correlation spectroscopy), HSQC (heteronuclear single-quantum correlation spectroscopy) and HMBC (heteronuclear multiple-bond correlation spectroscopy);MS (mass-spectrometry). The yields ranged from good to excellent (47% - 93%) under mild reaction conditions. It would indicate a high selectivity in the one-step work procedure. These products (3a-f) and derivatives have a potential academic and industrial use as key intermediates, in special, for application in crop protection.

Synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with potential bioactivity in PEG-400

An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The key advantages of this protocol are the shorter reaction time,higher yields,lower cost,simple workup,and environment-friendly compared to conventional organic solvent reaction.The present method does not involve any hazardous organic solvent or catalyst.

Synthesis, Crystal Structure, Antibacterial Activities and Theoretical Computation of 3-(2-Hydroxybenzly)-4-(4-isopropylbenzyl- ideneamino)-(1H)-1,2,4-triazole-5-thione

The title compound C18H18N4OS has been synthesized by the reaction of 3-（2-hydroxy- benzyl）-4-amino-（1H）-1,2,4-triazole-5-thione with 4-isopropylbenzaldehyde in ethanol and characterized by IR, ^1H NMR spectra and elemental analysis. Its structure was determined by X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 11.605（2）, b = 7.401（1）, c = 20.339（2） A, β= 103.05（2）°, V= 1701.8（4） A^3, Z = 4, Mr = 338.42,μ = 0.202 mm^-1, Dc = 1.321 g/cm^3 and F（000） = 712. The structure was solved by direct methods and refined to R = 0.0428 and wR = 0.1069. Due to the intramolecular O-H…N hydrogen bond and π-π stacking interactions between the benzene （C（1）～C（6）） and triazole rings, the two planes are essentially coplanar. Their biological activities have been measured, showing this type of compound has certain antibacterial activity for Staphylococous aureus and Bacillus subtilis. Based on the quantum chemistry calculation at the RHF/6-31G level, the frontier orbitals and electrostatic potential of the title compound were also discussed.

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.

Auxiliary Ligands Mediated One- and Two-dimensional Cd(Ⅱ) Coordination Polymers Incorporating Methyl-3- hydroxy-5-carboxy-2-Thiophenecarboxylate Ligand

Two N-donor ligands mediated Cd（Ⅱ） coordination polymers, namely,[Cd（L）（dmpz）2]n （1） and {[Cd（L）（atr）05（H20）]（H2O）}n （2） （H2L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate, dmpz = 3,5-dimethylpyrazole, and atr= 4-amino-l,2,4-triazole）, havebeen produced. Their structures were characterized by single-crystal X-ray diffraction analysis,elemental analyses and infrared spectra. Compound 1 possesses a one-dimensional （1D） chainstructure and is finally extended into a three-dimensional （3D） supramolecular architecturethough hydrogen bonding interactions. Compound 2 features a two-dimensional （2D） networkwith 4-connected sql topology based on dinuclear Cd（Ⅱ） clusters as nodes, which is alsoassembled into a 3D supramolecular architecture through hydrogen bonding interactions.Furthermore, compounds 1 and 2 exhibit high thermal stabilities and intense fluorescent emissionin the solid, and can be explored as potential luminescent materials.

Studies on 3-Amino-4-(1H-tetrazol-5-yl)-furazan:Crystal Structure, Thermal Behavior and Energetic Performance

The structure of 4-amino-3-(5-tetrazolate)-fiirazan(HAFT) was characterized by single crystal X-ray diffraction. The thermal decomposition process of HAFT was investigated by MS-FTIR-DSC-TG coupling technique. The result shows that the exothermic process occurs from 278.7-350℃, with a peak temperature of 324.7℃. The thennal decomposition gaseous products of HAFT are NO2, CO2, HCN, CO, NH3 and H2O. The detonation velocity and detonation pressure of HAFT were calculated by the nitrogen equivalent equation. The detonation velocity of HAFT is 7727.46 m/s, which is higher than that of TNT(7178 m/s). The detonation pressure of HAFT(25.27 GPa) is satisfactory. The sensitivity tests reveal HAFT possesses excellent insensitivities to impact and friction.

Improvement in the synthesis of 2-(5-amino-1,2,4-thiadiazol-3- yl)-2-(Z)-methoxyiminoacetic acid 2-benzothiazolyl thioester

2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-(Z)-meth-oxyiminoacetic acid 2-benzothiazolyl thioester(III),an important intermediate of the fourth generation cephalos-porins,was efficiently synthesized by reacting 2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(Z)-methoxyiminoacetic acid(I)with 2,29-dibenzothiazole disulfide(II)in the presence of triphenylphosphine.Effects of reaction time,temperature,solvents,catalysts and feeding molar ratio on the yield and quality of products were investigated,and an im-proved procedure suitable for industrial production was established.Using 1,2-dichloroethane as solvent,triphe-nylphosphine as reducer,and triethylamine as catalyst,n(I):n(II):n(triphenylphosphine)51.0:1.0:1.0,the product was obtained at room temperature in 98.1%yield.The purity of the product without further purification is 98.7%determined by HPLC method.This procedure could be a suitable alternative to the traditional processes because of its easy handling,high yield and low cost.

Improved microwave-assisted catalyst-free synthesis of9-aryl-5,9-dihydropyrimido[4,5-d][1,2,4]triazolo[1,5-a]pyrimidine-6,8(4H,7H)-dione derivatives

Agreen regioselective synthesis of some new and known 9-aryl-5,9-dihydropyrimido[4,5-d][l,2,4]triazolo[1,5-a]pyrimidine-6,8（4H,7H）-diones has been described via the microwave-assisted one-pot reaction of 3-amino-1H-1,2,4-triazoles,aromatic aldehydes and barbituric acids under solvent- and catalyst-free conditions.This operationally simple procedure is less laborious and provides a better scope than previously reported procedures.

An environmentally friendly synthesis of 1,4-dihydropyrano[2,3-c]pyrazole derivatives catalyzed by tungstate sulfuric acid

An efficient three-component synthesis of 6-amino-4-aryl-5-cyano-3-metriyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazoles via a reaction between 3-methyl-1-phenyl-2-pyrazolin-5-one,aromatic aldehydes and malononitrile using tungstate sulfuric acid as a catalyst was described.Mild conditions,good to excellent yields,easily available catalyst and easy work-up are the key features of this method.

Solvent-free preparation of arylaminotetrazole derivatives using aluminum(Ⅲ) hydrogensulfate as an effective catalyst

An efficient and simple method for the preparation of 5-arylamino-1H-tetrazole and 1-aryl-5-amino-1H-tetrazole derivatives is reported using aluminum（Ⅲ） hydrogensulfate（Al（HSO4）3） as an effective heterogeneous catalyst from secondary arylcyanamides. Generally,when the substitution in arylcyanamide is strongly electron-withdrawing the position of equilibrium would shift toward the isomer of 1-aryl-5-amino-1H-tetrazole（B） and as the electron-donating of substituent increased,the position of equilibrium is shifted toward the isomer of 5-arylamino-1H-tetrazole（A）.The present methodology offers several advantages,such as excellent yields,short reaction times,easy work-up and greener conditions.

Utility of Styrylpyrazoloformimidate in the Synthesis of Fused Heterocyclic Compounds

Refluxing of (E)-5-amino-1-phenyl-3-styryl-1H-pyrazole-4-carbonitrile 2 with triethylor-thoformate in acetic anhydride afforded the corresponding formimidate 3. Treatment of 3 with hydrazine hydrate in ethanol afforded amino imino compound 4. Reaction of 4 with diethyl dicarbonate at reflux gave (E)-7-phenyl-9-styryl-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine 7. Refluxing of 4 with hydrazine hydrate afforded (E)-4-hydrazinyl-1-phenyl-3-styryl-1H-pyrazolo[3,4-d] pyrimidine 8. Treatment of the latter compound 8 with aldehydes in boiling ethanol in the presence of acetic acid afforded the corresponding hydrazone 10. Oxidative cyclization of the hydrazone 10 led to the formation of pyrazolo[4,3-e][1,2,4]triazolo[4,3-c]pyrimidine 11. The latter products re-arranged to pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidines 13. The structures of the new products were established on the basis of elemental analysis and spectral data.

Design,synthesis and antimicrobial activities of 1,2,3-triazole derivatives

Fifteen 1-（4-substituted phenyl）-4-（4-bromophenyl）-5-（halo-o-hydroxyphenyl）imino-1,2,3-triazoles were designed and synthe- sized based on rational combination of 1,2,3-triazoles and （halo）o-hydroxyphenyl group according to the superposition principle of reinforcement of biological activities. All the compounds were tested to an in vitro antimicrobial screening against M.a. and E.c.. Compounds IIe-IIo exhibited more potent antimicrobial activities against M.a. and E.c. than triclosan and fluconazole, which provided valuable information to further study of novel antimicrobial research.

Designing energetic covalent organic frameworks for stabilizing high-energy compounds

As an emerging high-energy compound,3-nitro-1,2,4-triazol-5-one(NTO)is used in military explosives and rocket propellants.However,the strong acidic corrosion of NTO,and the high sensitivity and poor thermostability of its salts,severely restrict their practical applications.Therefore,a novel strategy to design and construct energetic covalent organic frameworks(COFs)is proposed in this study.We have successfully prepared a two-dimensional crystalline energetic COF(named ECOF-1)assembled from triaminoguanidine salt,in which NTO anions are trapped in the porous framework via the ionic interaction and hydrogen bonds.The results show that ECOF-1 exhibits superior thermal stability than energetic salt of NTO.It also exhibits insensitivity and excellent heat of detonation of 7,971.71 kJ·kg−1.ECOF-1 greatly inhibits the corrosiveness of NTO.In prospect,energetic COFs are promising as a functional platform to design high-energy and insensitive energetic materials.

Synthesis of some novel divalent transition metal complexes as antimicrobials

A novel series of transition metal complexes have been synthesized from the reaction of 5-（（3-（methylthio）-5-（pyridin-4-yl）-4H- 1,2,4-triazol-4-ylamino）melhyl）quinolm-8-ol with transition metal salts.The structures of these compounds have been elucidated by elemental and spectral analysis.Furthermore,compounds were screened for in vitro antimicrobial activity against the representative panel of two Gram-positive and two Gram-negative bacteria and two strains of fungus.The various compounds show potent inhibitory action against test organisms.