Isomers of 4‐amino‐1,3‐dinitrotriazol‐5‐one‐2‐oxide (ADNTONO) are of interest in the contest of insensitive explosives and were found to have true local energy minima at the DFT‐B3LYP/aug‐cc‐pVDZ level. The optimized structures, vibrational frequencies and thermodynamic values for triazol‐5‐one N‐oxides were obtained in their ground state. Kamlet‐Jacob equations were used to evaluate the performance properties. The detonation properties of ADNTONO (D=10.15 to 10.46 km s−1, P=50.86 to 54.25 GPa) are higher compared with those of 1,1‐diamino‐2,2‐dinitroethylene (D=8.87 km s−1, P=32.75 GPa), 5‐nitro‐1,2,4‐triazol‐3‐one (D=8.56 km s−1, P=31.12 GPa), 1,2,4,5‐tetrazine‐3,6‐diamine‐1,4‐dioxide (D=8.78 km s−1, P=31.0 GPa), 1‐amino‐3,4,5‐trinitropyrazole (D=9.31 km s−1, P=40.13 GPa), 4,4′‐dinitro‐3,3′‐bifurazan (D=8.80 km s−1, P=35.60 GPa) and 3,4‐bis(3‐nitrofurazan‐4‐yl)furoxan (D=9.25 km s−1, P=39.54 GPa). The NH2 group(s) appears to be particularly promising area for investigation since it may lead to two desirable consequences of higher stability (insensitivity), higher density, and thus detonation velocity and pressure. 相似文献
Some thermodynamic and explosive properties of the recently reported 1‐azido‐2‐nitro‐2‐azapropane (ANAP) have been determined in a combined computational ab initio (MP2/aug‐cc‐pVDZ) and EXPLO5 (Becker–Kistiakowsky–Wilson's equation of state, BKW EOS) study. The enthalpy of formation of ANAP in the liquid phase was calculated to be ΔfH°, ANAP(l)=+297.1 kJ mol−1. The heat of detonation (Qv), the detonation pressure (P), and the detonation velocity of ANAP were calculated to be Qv=−6088 kJ kg−1, P=23.8 GPa, D=8033 m s−1. A mixture of ANAP and tetranitromethane (TNM) was investigated in an attempt to tailor the impact sensitivity of ANAP, but results obtained indicate that the mixture is almost as sensitive as pure ANAP. On the other hand, ANAP and TNM were found to be chemically compatible (1H, 13C, 14N NMR; DSC) and a 1 : 1 mixture (by weight) of both components was calculated to have superior explosive properties than either of the individual components: Qv=−6848 kJ kg−1, P=27.0 GPa, D=8284 m s−1. 相似文献
The enthalpies of formation of six 1,2,3,4‐tetrazine‐based compounds were calculated according to the Density Functional Theory BOP/TNP method and by using homodesmotic reaction designs. Their detonation performances, including detonation velocity and pressure, were predicted in terms of the Stine equations. The 1,2,3,4‐Tetrazine‐based compounds labeled A, B, C, D, and F are powerful high‐energy compounds. The detonation performances of A and B, including detonation velocity, and detonation pressure, are superior to that of the current high‐energy explosive CL‐20. The detonation velocity, detonation pressure, and oxygen balance of 1,2,3,4‐tetrazine related oxo derivatives can be improved by partial oxidation of the nitrogen atoms in the tetrazine ring, but further oxidation causes reduction of the enthalpies and specific impulses of the oxo derivatives. Calculation of the molecular resonance energies indicated that E [C6N12] and F have more negative values, i.e, the ring strain energies of their configurations are high, whereas the resonance energies of C and D are low, only compound B has a very positive resonance energy. Considering energy and stability, B is a promising compound for practical use with both high energy and low sensitivity. 相似文献
A new primary explosive, the silver salt of 4,6‐diazido‐N‐nitro‐1,3,5‐triazine‐2‐amine (AgDANT), was synthesized and characterized. AgDANT was prepared with a 97 % yield and characterized by IR spectroscopy, single‐crystal X‐ray diffraction, and DTA. The crystal density of AgDANT is 2.530 g cm−3 and the molecule consists of a centro‐symmetric dimer with a high degree of planarity. The intramolecular Ag Ag distance is relatively low (331 pm) and can be considered as a strong argentophilic interaction. AgDANT is non‐hygroscopic and its solubility in water (1.27 mg in 100 mL at 23 °C) is on a similar level of solubility to that of silver azide. The sensitivity of AgDANT to impact is slightly higher than that for MF, sensitivity to friction is the same as for LA, and sensitivity to electric discharge is between that for LS and MF. Initiation efficiency of AgDANT was tested in electric detonators and compared to dextrinated lead azide (initiation efficiency of AgDANT is 40 mg for PETN secondary charge). The thermal resistance of detonators with AgDANT is satisfactory; all detonators were fully functional after exposure at 65 °C (30 d) and 85 °C (2 d). 相似文献
The development of nucleic acid derivatives to generate novel medical treatments has become increasingly popular, but the high vulnerability of oligonucleotides to nucleases limits their practical use. We explored the possibility of increasing the stability against 3′‐exonucleases by replacing the two 3′‐terminal nucleotides by N‐ethyl‐N‐coupled nucleosides. Molecular dynamics simulations of 3′‐N‐ethyl‐N‐modified DNA:Klenow fragment complexes suggested that this kind of alteration has negative effects on the correct positioning of the adjacent scissile phosphodiester bond at the active site of the enzyme, and accordingly was expected to protect the oligonucleotide from degradation. We verified that these modifications conferred complete resistance to 3′‐exonucleases. Furthermore, cellular RNAi experiments with 3′‐N‐ethyl‐N‐modified siRNAs showed that these modifications were compatible with the RNAi machinery. Overall, our experimental and theoretical studies strongly suggest that these modified oligonucleotides could be valuable for therapeutic applications. 相似文献
4,6‐Diazido‐N‐nitro‐1,3,5‐triazine‐2‐amine (DANT) was prepared with a 35 % yield from cyanuric chloride in a three step process. DANT was characterized by IR and NMR spectroscopy (1H, 13C, 15N), single‐crystal X‐ray diffraction, and DTA. The crystal density of DANT is 1.849 g cm−3. The cyclization of one azido group and one nitrogen atom of the triazine group giving tetrazole was observed for DANT in a dimethyl sulfoxide solution using NMR spectroscopy. An equilibrium exists between the original DANT molecule and its cyclic form at a ratio of 7 : 3. The sensitivity of DANT to impact is between that for PETN and RDX, sensitivity to friction is between that for lead azide and PETN, and sensitivity to electric discharge is about the same as for PETN. DANT′s heat of combustion is 2060 kJ mol−1. 相似文献
A facile highly regioselective process is described for the formation of 4‐chloromethyl‐1,3‐oxazoles from 1,3‐oxazole N‐oxide/HCl salts. An explanation is presented for the high regioselectivity in deoxygenation‐chlorination using POCl3 with HCl salts compared to the corresponding free N‐oxides. The method is quite general and the products are isolated by direct precipitation in all cases studied. 相似文献
Summary: Polyelectrolyte hydrogels containing diprotic acid moieties sensitive to ionic strength changes of the swelling medium were synthesized from N,N‐diethylaminoethyl methacrylate (DEAEMA), N‐vinyl‐2‐pyrrolidone (VP) and itaconic acid (IA) by using ammonium persulfate (APS) as a free radical initiator in the presence of the cross‐linker, methylenebisacrylamide (MBAAm). The swelling behavior of the ionic poly[(N,N‐diethylaminoethyl methacrylate)‐co‐(N‐vinyl‐2‐pyrrolidone)] [P(DEAEMA/VP)] hydrogels were investigated in pure water; in NaCI solutions with pH 4 and 9; and in water‐acetone mixtures depending on the IA content in the hydrogel. The average molecular mass between cross‐links ( ) and polymer‐solvent interaction parameter (χ) of the hydrogels were determined from equilibrium swelling values. The pulsatile swelling behavior was also observed in response to solvent changes between the solution in water and in acetone. The equilibrium swelling ratio of these hydrogels was basically unaffected with change in temperature. The swelling variations were explained according to the swelling theory based on the hydrogel chemical structure.
Pulsatile swelling behavior of ionic P(DEAEMA/VP) hydrogels in response to solvent changes between water and acetone at 25 °C. 相似文献
This study reports the preparation of 1‐amino‐1,2,3‐triazole‐3‐oxide (DPX2) and its transformation to 1,2,3,4‐tetrazine‐1‐oxide. DPX‐2 provides insight into a novel N‐oxide/N‐amino high‐nitrogen system, being the first energetic material in this class. The ability of this material to undergo a nitrene insertion forming 1,2,3,4‐tetrazine‐1‐oxide was also studied, and evidence for this material, the first non‐benzoannulated 1,2,3,4‐tetrazine‐1‐oxide, is presented. The existence of both of these materials opens new strategies in energetic materials design. DPX2 was characterized chemically (Infrared, Raman, NMR, X‐ray) and as a high explosive in terms of energetic performances (detonation velocity, pressure, etc.) and sensitivities (impact, friction, electrostatic). DPX‐2 was found to possess good thermal stability and moderate sensitivities, indicating the viability of N‐amino N‐oxides as a strategy for the preparation of new energetic materials. 相似文献
Herein we report the synthesis and neuroprotective effects of new N‐alkyl‐1,2,4‐oxadiazolidine‐3,5‐diones and their corresponding synthetic intermediates, N‐alkylhydroxylamines and N‐1‐alkyl‐3‐carbonyl‐1‐hydroxyureas, in an in vitro model of ischemia. We found five analogues that protect HT22 cells from death in the concentration range of 1–5 μM . Because members of the MAP kinase family are known to be key players in nerve cell survival and death, we characterized the role of these kinases in the neuroprotective mechanisms of the newly synthesized analogues. The results indicate that these compounds provide neuroprotection through distinct mechanisms of action.相似文献
The oxidizing system of tert‐butyl hydroperoxide (TBHP) and tetrabutylammonium iodide (TBAI) is capable of generating α‐(arylaminocarbonyl)iminyl radicals from ethyl 2‐(N‐arylcarbamoyl)‐2‐iminoacetates. These iminyl radicals preferably undergo intramolecular ipso attack on the benzene ring to give azaspirocyclohexadienyl radicals, which are readily captured by molecular oxygen under an oxygen atmosphere to yield azaspirocyclohexadienones. In the absence of oxygen, the reaction affords quinoxalin‐2‐one products. This oxidizing system is also effective to convert α‐aryl‐α‐azido‐N‐arylamides to the corresponding iminyl radicals under basic conditions (sodium tert‐butoxide, t‐BuONa), and the subsequent cyclization of these iminyl radicals results in the formation of azaspirocyclohexadienone products in high yields under an oxygen atmosphere. Plausible mechanisms are proposed to rationalize the experimental results, and factors influencing the reactions are discussed.
A novel palladium‐catalyzed intramolecular tandem annulation method is presented for the synthesis of 3‐[5H‐dibenzo[b,e]azepin‐11(6H)‐ylidene]indolin‐2‐ones. This method allows the conversion of various 3‐[2‐(2‐iodobenzylamino)aryl]‐N‐arylpropiolamides to the corresponding 3‐[5H‐dibenzo[b,e]azepin‐11(6H)‐ylidene]indolin‐2‐ones through the diarylation of an alkyne. 相似文献
Highly efficient syntheses of indolo[2,1‐a]isoquinolines, indolo[2,1‐a][2]benzazepines, pyrrolo[2,1‐a]isoquinolines and pyrrolo[1,2‐a]benzazepines in excellent yields have been achieved by the intramolecular photochemical cross‐coupling reactions of 3‐acyl‐2‐halo‐N‐(ω‐arylalkyl)indoles and 2‐chloro‐N‐(ω‐arylalkyl)pyrrole‐3‐carbaldehydes in acetone. A new heterocyclic ring system – pyrrolo[1,2‐d][1,4]benzoxazepine – has also been constructed for the first time in this work by the photocyclization of 2‐chloro‐N‐(2‐phenoxyethyl)pyrrole‐3‐carbaldehyde. 相似文献