Thermal Behavior of 2‐(Dinitromethylene)‐1,3‐diazacyclopentane

A new compound, 2‐(dinitromethylene)‐1,3‐diazacyclopentane (DNDZ), was prepared by the reaction of 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) with 1,2‐diaminoethane in N‐methylpyrrolidone (NMP). Thermal decomposition of DNDZ was studied under non‐isothermal conditions by DSC, TG/DTG methods, and the enthalpy, apparent activation energy and pre‐exponential factor of the exothermic decomposition reaction were obtained as 317.13 kJ·mol^?1, 269.7 kJ·mol^?1 and 10^24.51 s^?1, respectively. The critical temperature of thermal explosion was 261.04°C. Specific heat capacity of DNDZ was determined with a micro‐DSC method and a theoretical calculation method, and the molar heat capacity was 205.41 J·mol^?1·K^?1 at 298.15 K. Adiabatic time‐to‐explosion was calculated to be a certain value between 263–289 s. DNDZ has higher thermal stability than FOX‐7.     

Synthesis,Crystal Structure and Thermal Behavior of 4,5‐Diacetoxyl‐2‐(dinitromethylene)‐imidazolidine

A new energetic material, 4,5‐diacetoxyl‐2‐(dinitromethylene)‐imidazolidine (DADNI), was synthesized by the reaction of 4,5‐dihydroxyl‐2‐(dinitromethylene)‐imidazolidine (DDNI) and acetic anhydride, and characterized by single crystal X‐ray diffraction. Crystal data for DADNI are monoclinic, space group C2/c, a=15.9167(3) Å, b=8.6816(4) Å, c=8.5209(3) Å, β=103.294(9)°, V=1145.9(3) ų, Z=4, µ=0.150 mm⁻¹, F(000)=600, D_c=1.682 g·cm⁻³, R₁=0.0565 and wR₂=0.1649. Thermal decomposition behavior of DADNI was studied and an intensely exothermic process was observed. The kinetic equation of the decomposition reaction is: dα/dT=(10^16.64/β)×4α^3/4exp(−1.582×10⁵/RT). The critical temperature of thermal explosion is 163.76°C. The specific heat capacity of DADNI was studied with micro‐DSC method and theoretical calculation method. The molar heat capacity is 343.30 J·mol⁻¹·K⁻¹ at 298.15 K. The adiabatic time‐to‐explosion of DADNI was calculated to be 87.7 s.     

Adsorption and Decomposition Mechanism of 1,1‐Diamino‐2,2‐dinitroethylene on Al(111) Surface by Periodic DFT Calculations

The adsorption of 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) molecule on the Al(111) surface was investigated by the generalized gradient approximation (GGA) of density functional theory (DFT). The calculations employ a supercell (4×4×2) slab model and three‐dimensional periodic boundary conditions. The strong attractive forces between oxygen and aluminum atoms induce the N? O bond breaking of the FOX‐7. Subsequently, the dissociated oxygen atoms and radical fragment of FOX‐7 oxidize the Al surface. The largest adsorption energy is ?940.5 kJ/mol. Most of charge transfer is 3.31e from the Al surface to the fragment of FOX‐7 molecule. We also investigated the adsorption and decomposition mechanism of FOX‐7 molecule on the Al(111) surface. The activation energy for the dissociation steps of P2 con?guration is as large as 428.8 kJ/mol, while activation energies of other con?gurations are much smaller, in range of 2.4 to 147.7 kJ/mol.     

G(FOX-7)的合成、晶体结构及量子化学研究

用1,1-二氨基-2,2-二硝基乙烯（FOX-7）和盐酸胍在KOH水溶液中合成了[HN=C(NH₂)₂]⁺(FOX-7)^---G(FOX-7),并培养出淡黄色单晶。化合物属正交晶系,空间群为P-bca,晶体结构参数为: a=1.0428(3)nm, b=0.73099(18)nm,c=2.2253(5)nm,V=1.6963(7) nm³,D_c=1.542 g/cm³,μ＝0.333 mm^-1,F(000)=864, Z=8。在分析分子晶体结构的基础上,采用B3LYP、HF和MP2三种方法在6-31+G(d)基组水平上对标题化合物进行几何全优化,并对其成键情况、原子电荷分布、分子轨道能量进行了分析。     

Structural Characterization and Thermal Behavior of 1-Amino-1-methylamino-2,2-dinitroethylene

A novel high energetic material, 1‐amino‐1‐methylamino‐2,2‐dinitroethylene (AMFOX‐7), was synthesized through 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) reacting with methylamine in N‐methyl pyrrolidone (NMP) at 80.0°C, and its structure was determined by single crystal X‐ray diffraction. The crystal is monoclinic, space group P2₁/m with crystal parameters of a=6.361(3) Å, b=7.462(4) Å, c=6.788(3) Å, β=107.367(9)°, V=307.5(3) ų, Z=2, µ=0.160 mm^?1, F(000)=168, D_c=1.751 g·cm^?3, R₁=0.0463 and wR₂=0.1102. Thermal decomposition of AMFOX‐7 was studied, and the enthalpy, apparent activation energy and pre‐exponential constant of the exothermic decomposition reaction are 303.0 kJ·mol^?1, 230.7 kJ·mol^?1 and 10^21.03 s^?1, respectively. The critical temperature of thermal explosion is 245.3°C. AMFOX‐7 has higher thermal stability than FOX‐7.     

1-氨基-1-肼基-2,2-二硝基乙烯（AHDNE）的非等温分解动力学，比热容和绝热至爆时间研究

利用DSC和TG/DTG法研究了1-氨基-1-肼基-2,2-二硝基乙烯（AHDNE）热分解行为及分解动力学,第一热分解过程的动力学方程为： ,其热爆炸临界温度为98.16 ºC。同时,利用微量热法测定了AHDNE的比热容,298.15K时的标准摩尔比热容为211.86 J•mol-1•K-1。计算得到了AHDNE的绝热至爆时间为59.21 s。AHDNE是不稳定的,其热稳定性远低于母体化合物FOX-7。     

Cs(DNDZ)的合成、晶体结构和热行为研究

合成了一种新型高能有机铯盐2-(二硝基亚甲基)-1,3-二氮杂环戊烷铯盐[Cs(DNDZ)],并培养出单晶。该晶体属单斜晶系,空间群P21/c,晶胞参数为:a=0.933 6(2)nm,b=0.677 42(14)nm,c=1.387 4(3)nm,β=101.173(2)°,V=0.860 8(3)nm3,Z=4,μ=4.292mm-1,F(000)=576,Dc=2.361 g.cm-3,R1=0.029 1,wR2=0.077 8。用非等温DSC,TG/DTG法研究了Cs(DNDZ)的热行为,第一放热分解反应的放热焓、表观活化能和指前因子分别为-1045 J.g-1,144.2 kJ.mol-1和1013.75s-1。其热爆炸的临界温度为181.48℃。Cs(DNDZ)热稳定性低于DNDZ。     

新型高能有机钾盐K(DNDZ)的晶体结构和热行为研究

合成了一种新型高能有机钾盐2-(二硝基亚甲基)-1,3-二氮杂环戊烷钾盐[K(DNDZ)],并培养出单晶。该晶体属单斜晶系,空间群P2₁/n,晶胞参数为：a=0.506 31(19) nm,b=1.336 2(5) nm,c=1.164 9(4) nm,β=99.860(6)°,V=0.776 5(5) nm³,Z=4,μ=0.674 mm^-1,F(000)=432,D_c=1.815 g·cm^-3。用非等温DSC法研究了K(DNDZ)的热行为,第一放热分解反应的放热焓、表观活化能和指前因子分别为444.75 kJ·mol^-1,152.2 kJ·mol^-1和10^13.92 s^-1。其热爆炸的临界温度为208.63 ℃。     

Non‐Isothermal Decomposition Kinetics,Specific Heat Capacity and Adiabatic Time‐to‐explosion of a Novel High Energy Material: 1‐Amino‐1‐Methylamino‐2,2‐Dinitroethylene (AMFOX‐7)

A novel high energy material, 1‐amino‐1‐methylamino‐2,2‐dinitroethlyene (AMFOX‐7), was synthesized by the reaction of 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) and methylamine aqueous solution in N‐methyl pyrrolidone at 80°C. The thermal behavior and non‐isothermal decomposition kinetics of AMFOX‐7 were studied with DSC and TG/DTG methods. The kinetic equation of thermal decomposition reaction can be expressed as: $ {\rm d\alpha /d}T = \frac{{10^{21.03}}}{{\rm \beta}}\frac{3}{2}\left({1 - {\rm \alpha}} \right)\left[{- 1{\rm n}\left({{\rm 1} - {\rm \alpha}} \right)} \right]^{\frac{1}{3}} \exp \left({- 2.292 \times 10^5 {\rm /}RT} \right) A novel high energy material, 1‐amino‐1‐methylamino‐2,2‐dinitroethlyene (AMFOX‐7), was synthesized by the reaction of 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) and methylamine aqueous solution in N‐methyl pyrrolidone at 80°C. The thermal behavior and non‐isothermal decomposition kinetics of AMFOX‐7 were studied with DSC and TG/DTG methods. The kinetic equation of thermal decomposition reaction can be expressed as: $ {\rm d\alpha /d}T = \frac{{10^{21.03}}}{{\rm \beta}}\frac{3}{2}\left({1 - {\rm \alpha}} \right)\left[{- 1{\rm n}\left({{\rm 1} - {\rm \alpha}} \right)} \right]^{\frac{1}{3}} \exp \left({- 2.292 \times 10^5 {\rm /}RT} \right) $. The critical temperature of thermal explosion of AMFOX‐7 is 244.89°C. The specific heat capacity of AMFOX‐7 was determined with micro‐DSC method and theoretical calculation method, and the standard molar specific heat capacity is 199.39 J·mol^?1·K^?1 at 298.15 K. Adiabatic time‐to‐explosion of AMFOX‐7 was also calculated to be 215.41 s. AMFOX‐7 has higher thermal stability than FOX‐7.     

Electrochemical Reduction of 4,4′‐(2,2,2‐Trichloroethane‐1,1‐diyl)‐ bis(chlorobenzene) (DDT) and 4,4′‐(2,2‐Dichloroethane‐1,1‐diyl)‐ bis(chlorobenzene) (DDD) at Carbon Cathodes in Dimethylformamide

In dimethylformamide containing tetramethylammonium tetrafluoroborate, cyclic voltammograms for reduction of 4,4′‐(2,2,2‐trichloroethane‐1,1‐diyl)bis(chlorobenzene) (DDT) at a glassy carbon cathode exhibit five waves, whereas three waves are observed for the reduction of 4,4′‐(2,2‐dichloroethane‐1,1‐diyl)bis(chlorobenzene) (DDD). Bulk electrolyses of DDT and DDD afford 4,4′‐(ethene‐1,1‐diyl)bis(chlorobenzene) (DDNU) as principal product (67–94%), together with 4,4′‐(2‐chloroethene‐1,1‐diyl)bis(chlorobenzene) (DDMU), 1‐chloro‐4‐styrylbenzene, and traces of both 1,1‐diphenylethane and 4,4′‐(ethane‐1,1‐diyl)bis(chlorobenzene) (DDO). For electrolyses of DDT and DDD, the coulometric n values are essentially 4 and 2, respectively. When DDT is reduced in the presence of a large excess of D₂O, the resulting DDNU and DDMU are almost fully deuterated, indicating that reductive cleavage of the carbon–chlorine bonds of DDT is a two‐electron process that involves carbanion intermediates. A mechanistic scheme is proposed to account for the formation of the various products.     

Formation of 2‐(Phenylsulfonyl)resorcinols (=2‐(Phenylsulfonyl)benzene‐1,3‐diols) from Symmetrically Substituted Maleic Anhydrides (=Furan‐2,5‐diones)

Treatment of symmetrically substituted maleic anhydrides (=furan‐2,5‐diones) 6 with lithium (phenylsulfonyl)methanide, followed by methylation of the adduct with MeI/K₂CO₃ in acetone, give the corresponding 4,5‐disubstituted 2‐methyl‐2‐(phenylsulfonyl)cyclopent‐4‐ene‐1,3‐diones 8 (Scheme 3). Reaction of the latter with lithium (phenylsulfonyl)methanide in THF (?78°) and then with 4 mol‐equiv. BuLi (?5° to r.t.) leads to 5,6‐disubstituted 4‐methyl‐2‐(phenylsulfonyl)benzene‐1,3‐diols 9 (Scheme 4).     

One‐Pot Synthesis of N,N‐Disubstituted (Z)‐4‐(Halomethylidene)‐4H‐3,1‐benzothiazin‐2‐amines from 2‐(2,2‐Dihaloethenyl)phenyl Isothiocyanates and Secondary Amines

We have developed a one‐pot procedure for the preparation of N,N‐disubstituted (Z)‐4‐(halomethylidene)‐4H‐3,1‐benzothiazin‐2‐amines 3 from 2‐(2,2‐dihaloethenyl)phenyl isothiocyanates 1 , easily accessible from known 2‐(2,2‐dihaloethenyl)benzenamines by a three‐step sequence, and secondary amines. Thus, the isothiocyanates 1 react with secondary amines to afford the corresponding thiourea derivatives, of which the treatment with NaH provides the desired products.     

无气味、实用的缩硫醛/酮化反应试剂：2-（1，3-二噻-2-亚基）-3-羰基丁酸甲酯

a-Oxo ketene dithioacetals, methyl 2-（1,3-dithian/dithiolan-2-ylidene）-3-oxobutanoate （2a/2b） prepared in nearly quantitative yields simply from methyl acetylacetate, carbon disulfide and 1,3-dibromopropane/1,2-dibromoethane in the presence of potassium carbonate, were investigated in the thioacetalization with various carbonyl compounds 3. It has been demonstrated that methyl 2-（1,3-dithian-2-ylidene）-3-oxobutanoate （2a） could act as a nonthiolic, odorless and practical thioacetalization reagent. A range of aldehydes and ketones 3 were converted into the corresponding dithioacetals 4 in high yields （up to 91%） in the presence of 2a. Moreover, 2a showed high chemoselectivity between aldehyde and ketone in thioacetalization.     

Regioselective Synthesis of 6‐[Chloro(difluoro)methyl]salicylates by [3+3] Cyclocondensations of 1,3‐Bis(trimethylsilyloxy)buta‐1,3‐dienes with 1‐Chloro‐1,1‐difluoro‐4‐(trimethylsilyloxy)pent‐3‐en‐2‐one

The TiCl₄‐mediated [3+3] cyclocondensation of various 1,3‐bis(trimethylsilyloxy)buta‐1,3‐dienes with 1‐chloro‐1,1‐difluoro‐4‐(trimethylsilyloxy)pent‐3‐en‐2‐one provides a regioselective access to novel 6‐(chlorodifluoromethyl)salicylates (=6‐(chlorodifluoromethyl)‐2‐hydroxybenzoates) with very good regioselectivity. For selected products, it was demonstrated that the CF₂Cl group can be transformed to CF₂H and CF₂(Allyl) by free‐radical reactions.     

Synthesis of (4Z)‐4‐(Arylmethylidene)‐5‐ethoxy‐1,3‐oxazolidine‐2‐thiones by the Reaction of Ethyl (2Z)‐3‐Aryl‐2‐isothiocyanatoprop‐2‐enoates with Organolithium Compounds

A convenient one‐pot method for the preparation of (4Z)‐4‐(arylmethylidene)‐5‐ethoxy‐1,3‐oxazolidine‐2‐thiones 2 and 3 from ethyl (2Z)‐3‐aryl‐2‐isothiocyanatoprop‐2‐enoates 1 , which can be easily prepared from ethyl 2‐azidoacetate and aromatic aldehydes, has been developed. Thus, these α‐isothiocyanato α,β‐unsaturated esters were treated with organolithium compounds, including lithium enolates of acetates, to provide 5‐substituted (4Z)‐4‐(arylmethylidene)‐5‐ethoxy‐1,3‐oxazolidine‐2‐thiones, 2 , and 2‐[(4Z)‐(4‐arylmethylidene)‐5‐ethoxy‐2‐thioxo‐1,3‐oxazolidin‐5‐yl]acetates, 3 .     

Regioselective Synthesis of 5‐(2‐Cyanoethyl)‐1,1′‐biphenyl‐2‐carboxylates by Formal [3+3] Cyclocondensations of 1,3‐Bis[(trimethylsilyl)oxy]buta‐ 1,3‐dienes

5‐(2‐Cyanoethyl)‐1,1′‐biphenyl‐2‐carboxylates were prepared by regioselective formal [3+3] cyclocondensations of 1,3‐bis[(trimethylsilyl)oxy]buta‐1,3‐dienes.     

Synthesis of 1,3‐Dihydro‐3‐oxo‐2‐benzofuran‐1‐carboxylates via Intramolecular Cyclization of 2‐[2‐(Dimethoxymethyl)phenyl]‐ 2‐hydroxyalkanoates Followed by Oxidation

A novel and efficient method for the preparation of 1,3‐dihydro‐3‐oxo‐2‐benzofuran‐1‐carboxylates 4 under mild conditions has been developed. Thus, the reaction of [2‐(dimethoxymethyl)phenyl]lithiums, generated easily from 1‐bromo‐2‐(dimethoxymethyl)benzenes 1 , with α‐keto esters gives the corresponding 2‐[2‐(dimethoxymethyl)phenyl]‐2‐hydroxyalkanoates 2 . The TsOH‐catalyzed cyclization of these hydroxy acetals is followed by the oxidation of the resulting cyclic acetals 3 with PCC to give the desired products in satisfactory yields. The reaction of [2‐(dimethoxymethyl)‐4,5‐dimethoxyphenyl]lithium with (MeOC?O)₂, followed by treatment with NaBH₄ or organolithiums, affords 2‐[2‐(dimethoxymethyl)‐4,5‐dimethoxyphenyl]‐2‐hydroxyalkanoates 6 , which can similarly be transformed into the corresponding 1,3‐dihydro‐3‐oxo‐2‐benzofuran‐1‐carboxylates 7 in reasonable yields.     

Effect of pH on the rotational conformations of 1,3‐diamino‐2‐hydroxypropane

The effect of pH on the rotational conformations of 1,3‐diamino‐2‐hydroxypropane in aqueous solution was investigated by proton NMR. Both the observed chemical shifts and coupling constants were used to calculate experimental pK_a values. The observed couplings were correlated with the expected couplings for the various possible staggered conformations to try to determine the pattern of conformations for the diamine and its conjugate acids. The best fits suggested a modest preference for the gauche–gauche conformation, especially at low pH, where the diprotonated hydroxydiamine predominates. In methanol, dimethyl sulfoxide and trichloromethane solutions, it was only possible to evaluate the conformational equilibria of the diamine. Slow proton exchange, which caused uncertainties in both chemical shifts and couplings for the monoprotonated and unprotonated diamine, nullified efforts to determine whether or not hydrogen bonding was important for these species in less polar solvents. Copyright © 2002 John Wiley & Sons, Ltd.     

2‐(Dinitromethylene)‐1‐nitro‐1, 3‐diazacyclopentane‐Based Energetic Salts

Energetic salts that contain nitrogen‐rich cations and the 2‐(dinitromethyl)‐3‐nitro‐1, 3‐diazacyclopent‐1‐ene anion were synthesized in high yield by direct neutralization reactions. The resulting salts were fully characterized by multinuclear NMR spectroscopy (¹H and ¹³C), vibrational spectroscopy (IR), elemental analysis, density and differential scanning calorimetry (DSC), and elemental analysis. Additionally, the structures of the ammonium ( 1 ) and isopropylideneaminoguanidinium ( 9 ) 2‐(dinitromethyl)‐3‐nitro‐1, 3‐diazacyclopent‐l‐ene salts were confirmed by single‐crystal X‐ray diffraction. Solid‐state ¹⁵N NMR spectroscopy was used as an effective technique to further determine the structure of some of the products. The densities of the energetic salts paired with organic cations fell between 1.50 and 1.79 g · cm^–3 as measured by a gas pycnometer. Based on the measured densities and calculated heats of formation, detonation pressures and velocities were calculated using Explo 5.05 and found to to be 25.2–35.5 GPa and 7949–9004 m · s^–1, respectively, which make them competitive energetic materials.     

Design,Synthesis, and Evaluation of 3‐((4‐(t‐Butyl)‐2‐(2‐benzylidenehydrazinyl)thiazol‐5‐yl)methyl)quinolin‐2(1H)‐ones as Neuraminidase Inhibitors

A series of novel 3‐((4‐(t‐butyl)‐2‐(2‐benzylidenehydrazinyl)thiazol‐5‐yl)methyl)quinolin‐2(1H)‐ones ( 7a – 7z ) were designed, synthesized and evaluated for their ability of inhibiting neuraminidase (NA) of in?uenza H1N1 virus. Some compounds displayed moderate influenza NA inhibitory activity. Compound 7l with the scaffold of 2‐(2‐(2‐methoxybenzylidene)hydrazinyl)thiazole was the best one, exhibiting moderate NA inhibitory activity with IC₅₀ of 44.66 µmol/L. Structure‐activity relationship showed that compounds with methoxy or hydroxy groups at the ortho position, fluorine and nitro groups at the meta position and chlorine and bromine groups at the para position of phenyl ring were more active. Docking study indicated that compound 7l has important interactions with some key residues (including Asp151, Glu119, Arg292, Tyr406, and Asn347) and binds to 430‐cavity adjacent to NA active site.