Molecular Dynamic Simulation of Melting Points of Trans-1,4,5,8- tetranitro-1,4,5,8-tetraazadacalin （TNAD） with Some Propellants

Molecular dynamic simulation was employed to predict the melting points Tm of TNAD/HMX, TNAD/RDX, TNAD/DINA, and TNAD/DNP systems （tans-1,4,5,8- tetranitro-1,4,5,8-tetraazadacalin （TNAD）, dinitropiperazine （DNP）, cyclotetramethylenetetranitroamine （HMX）, cyclotrimethylenetrinitramine （RDX）, and N-nitrodihydroxyethylaminedinitrate （DINA））. Tm was determined from the inflexion point on the curve of mean specific volume vs. temperature. The result shows that the Tm values of TNAD/HMX, TNAD/RDX, and TNAD/DINA systems are 500, 536, and 488 K, respectively. The TNAD/DNP system has no obvious Tm value, which shows the system is insoluble. Using Tm, the solubility of the four systems was analyzed. The radial distribution functions of the four systems were analyzed and the main intermolecular forces between TNAD and other energetic components are short-range interactions. The better the solubility is, the stronger the intermoleenlar interaction is. In addition, the force field energy at different temperature was also analyzed to predict Tm of the four systems.

Synthesis and Crystal Structure of Trans-4-[(5-(2,4-Dichlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl)methyleneamino]-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one

The title compound trans-4-[（5-（2,4-dichlorophenoxy）-3-methyl- 1-phenyl-1H-pyrazol-4-yl）methyleneamino]- 1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 3 （C28H23Cl2N5O2, Mr = 532.41） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1- with a = 8.9438（4）, b = 11.6065（5）, c = 14.2215（6）A, α = 112.566（1）, β = 92.324（2）, γ = 102.91（1）°, V= 1315.65（10） A^3, Z = 2, Dc = 1.344 g/cm^3,μ（MoKa） = 0.282 mm^-1, λ = 0.71073 A, F（000） = 552, the final R = 0.0587 and wR = 0.1578 for 5071 observed reflections （I 〉 2σ（I））. X-ray analysis reveals that the product is a thermodynamically stable trans isomer. Intra- and intermolecular C（ 12）-H（12）…O（1） and C（28）-H（28）...O（1）# 1 hydrogen bonds were observed in the title compound.

Synthesis of 1-Bromo-3-methoxy-4-propoxy-5-iodobenzene——A Novel Efficient Process for the Synthesis of Brominated Aromatic Compound

The reaction of aromatic carboxylic acid with oxalyl chloride gives rise to the corres- ponding acid chloride which without purification is treated with the sodium salt of mercapto- pyridine oxide in the presence of 2,2-azo-bisisobutyronitrile (AIBN), radical initiator to give a brominated aromatic compound. After etherification and oxidation, 5-iodovaniline was converted to trisubstituted benzene carboxylic acid which give 1-bromo-3-methoxy-4-propoxy-5-iodo- benzene by this new brominating process with a yield of 74 %.

Room Temperature Phosphorescence of 1-Bromo-4-(bromoacetyl) naphthalene Induced by Sodium Deoxycholate

Sodium deoxycholate (NaDOC) could induce 1-bromo-4-(bromoacetyl) naphthalene (BBAN) to emit strong room temperature phosphorescence (RTP). Measurements of phosphore- scence spectra, peak intensity and polarization were used to investigate the solubilization of BBAN as a function of NaDOC concentration.

Synthesis, Structure and Geometrical Calculation of a Novel Co-crystal of {[4-Bromo-2-(benzimidazol-2-yl)phenolato][2-(1-butylbenzimidazol-2-yl)phenolato]zinc(Ⅱ)] and Bis[μ-2-(1-butylbenzimidazol-2-yl)phenolato]-1κN^3:2κO;1κO:2κN^3-bis{[2-(1-butylbe

The title compound has been synthesized and characterized crystallographicaUy. It is a co-crystal consisting of two different neutral zinc（H） complexes with Hbpbm （Hbpbm = 4- bromo-2-（benzimidazol-2-yl）phenol） and Hnpbm （Hnpbm = 2-（1-butylbenzimidazol-2-yl）phenol）. One is a monomeric mixed-ligand complex of [Zn（bpbm）（npbm）] 1 and the other a dimer of [Zn2（npbm）4] 2 with their ratio of 2：1. Thus the overall formula for the title compound is 21.2. Adjacent 1 and 2 are connected to each other by intermolecular hydrogen bonding interactions in the lattice. The crystal data： monoclinic, space group P21/c, a = 15.0141（12）, b = 20.9941（17）, c = 18.4686（15） A, β = 97.445（2）°, V = 5772.4（8） A^3, Mr= 2429.68, Z = 2, Dc = 1.398 g/cm^3,μ = 1.579 -1 mm , F（000） = 2504, R = 0.0637 and wR = 0.1771 for 6464 observed reflections （I 〉 2σ（I））. The geometrical structure for 1 has also been theoretically optimized and compared with the experimental one.

Synthesis and Crystal Structure of 4-Bromo-5-ethoxy-3-methyl-5- (naphthalen-1-yl)-1-tosyl-1H-pyrrol-2(5H)-one

The title compound 4-bromo-5-ethoxy-3-methyl-5-（naphthalen-l-yl）-l-tosyl-lH- pyrrol-2（5H）-one 1 （C24H22BrNO4S, Mr = 500.40） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 8.8562（15）, b = 18.118（3）, c = 14.055（2）A, β = 99.855（3）^o, V= 2221.9（6）A3, Z = 4, Dc = 1.496 g/cm^3,μ= 1.975 mm^-1, 2 = 0.71073A, F（000） = 1024, R = 0.0607 and wR = 0.1371.

Synthesis and Crystal Structure of N1-(2-(4-Bromo-2-nitrophenoxy)-2-dimethyl acyloxymethyl)-5-fluorouracil

The title compound N1-（2-（4-bromo-2-nitrophenoxy）-2-dimethyl acyloxymethyl）-5-fluorouracil（C15H13BrFN3O7, Mr = 446.19） was synthesized and structurally characterized by ^1H-NMR, -（13）C-NMR, ESI-MS and single-crystal X-ray diffraction. The compound crystallizes in triclinic, space group P1, with a = 8.3325（6）, b = 10.1808（13）, c = 11.8194（16） A, α = 73.194（12）, β= 72.351（9）, γ = 89.509（8）o, V = 911.2（2） A^3, Z = 2, T = 300.79（10） K, μ（Cu Kα） = 3.578 mm^-1, Dc = 1.626 g/cm3, F（000） = 448.0, GOF = 1.060, 5723 reflections measured（8.232≤2θ≤139.592°）, 3339 unique（Rint = 0.0184, Rsigma = 0.0254） which were used in all calculations. The final R = 0.0517（I 〉 2s（I）） and wR = 0.1494（all data）. Hydrogen bonds and π-π interactions together stabilize the structure of the molecule. The preliminary biological test shows that the title compound has good antitumor activity against A549 in vitro and lower toxicity to normal cells.

Synthesis and Crystal Structure of Cobalt(II) Complex [Co(H_2O)_2(bpe)(OAc)_2]·4,4'-dpdo

The reaction of Co(OAc)2 with bpe and 4,4?-dpdo in an aqueous-alcohol solution affords the formation of red crystals of [Co(H2O)2(bpe)(OAc)2]?4,4?-dpdo (bpe = trans-1,2-bis(4- pyridyl)ethylene, 4,4?-dpdo = 4,4?-dipyridyl N,N?-oxide). The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with a = 7.6146(9), b = 8.6691(11), c = 10.3440(11) ?, α = 88.311(3), β = 76.992(3), γ = 75.809(3)°, V = 644.76(13) ?3, Z = 1, C26H28CoN4O8, Mr = 583.45, Dc = 1.503 g/cm3, μ = 0.724 mm-1, F(000) = 303, T = 223(2) K, the final R = 0.0477 and wR = 0.1177 for 3199 observed reflections with I > 2σ(I). In the crystal the cobalt atom is six-coordinated by oxygen atoms from two carboxylic molecules, two nitrogen atoms from the bpe ligands and two water molecules, completing an octahedral geometry. The structure of the title complex consists of neutral chains containing cobalt(II) ions bridged by mutually trans bpe molecules. The adjacent chains are connected through weak hydrogen bonds to form a two-dimensional structure.

Stress-induced Solid-Solid Crystal Transition in Trans-1,4-polyisoprene

The polymorphic transition of trans-1,4-polyisoprene(TPI) during stretching was investigated by in situ wide-angle X-ray diffraction and Fourier transform infrared spectroscopy. The influences of the initial structure, stretching temperature, and strain rate on the contents of different crystal modifications(α, β) were explored. The results confirm that the α-β transition occurs during stretching of TPI that only contains αcrystal(α-TPI). When the stress is relaxed, the β crystal formed during stretching remains, which indicates that the transition is irreversible. On the other hand, stretching of TPI that only contains β crystal(β-TPI) results in orientated β crystal. No β-α transition occurs during stretching. The different structures of stretched α-TPI and β-TPI exclude the previously proposed "melting-recrystallization mechanism". The α-β transition depends significantly on temperature and strain rate, indicating the transition is governed both by thermodynamics and kinetics. Our results support a solid-solid transition mechanism rather than a melting-recrystallization mechanism. The irreversible nature of the transition is attributed to the metastability of the β phase in the unstretched state. Different from the "β phases" that appear in polymers with stress-induced reversible transitions, e.g. poly(butylene terephthalate) and poly(butylene succinate), the stability of β phase in TPI is high that can be long-lived.The strain rate dependence of α-β transition hinders the determination of critical stress for the transition. It further indicates that the local stress within the sample is more heterogeneous at higher strain rates.

Synthesis of Well-defined Telechelic Trans-1,4-polyisoprene by Oxidative Cleavage

Synthesis of telechelic trans-1,4-polyisoprenes（TPI： trans-structure ＆gt; 95%） was evaluated based on two different methods of oxidative cleavage（indirect cleavage： first epoxidation of TPI, then the selective cleavage of epoxidized units in epoxidized trans-1,4-polyisoprene（ETPI） and direct cleavage of isoprene units in TPI）. The influence of solvents and the ratio of oxidative agents was investigated by 1H-NMR and 13C-NMR. A series of well-defined telechelic TPI with double terminated functional groups and less side reaction（molecular weight distribution range： 1.96？2.26） were synthesized by indirect cleavage in chloroform. Telechelic TPI showed similar crystallization behavior with TPI and interesting cold crystallization behavior characterized by DSC.

Fabrication of Trans-1,4-polyisoprene Nanofibers by Electrospinning and Its Crystallization Behavior and Mechanism

Trans-1,4-polyisoprene（TPI） nanofibers have been fabricated successfully through electrospinning technology.Through the control of electrospinning parameters, highly crystallized TPI fresh fibers composed mainly of β phase were produced. Morphology and diameter of TPI nanofibers can be controlled by adjusting the electrospinning conditions. The in situ observations of FTIR spectra revealed that the crystallinity of the TPI fibers decreased with aging. While for TPI nanofibers aging at 45 °C for 24 h, a decrease in crystallinity as well as β to a transformation was observed with aging and these changings happened in the first 50 h during aging. The mechanism for β-TPI formation during electrospinning process and the reduced crystallinity with aging were proposed.

Competition of Aromatic Bromination and Nitration in Concentrated Sulfuric Acid

Composition of bromine and nitric acid in concentrated sulfuric acid is effective for bromination of strongly deactivated aromatic compounds and for nitration and bromination of moderately deactivated compounds in one stage. The question why brominating agent is more reactive than nitrating agent in relation to strongly deactivated aromatic compounds and is less reactive in relation to moderate deactivated ones is discussed.

Synthesis and anti-HIV activities of phorbol derivatives

In this study,37 derivatives of phorbol esters were synthesized and their anti-HIV-1 activities evaluated,building upon our previous synthesis of 51 phorbol derivatives.12-Para-electron-acceptor-trans-cinnamoyl-13-decanoyl phorbol derivatives stood out,demonstrating remarkable anti-HIV-1 activities and inhibitory effects on syncytia formation.These derivatives exhibited a higher safety index compared with the positive control drug.Among them,12-(trans-4-fluorocinnamoyl)-13-decanoyl phorbol,designated as compound 3c,exhibited the most potent anti-HIV-1 activity(EC_(50)2.9 nmol·L^(−1),CC50/EC_(50)11117.24)and significantly inhibited the formation of syncytium(EC_(50)7.0 nmol·L^(−1),CC50/EC_(50)4891.43).Moreover,compound 3c is hypothesized to act both as an HIV-1 entry inhibitor and as an HIV-1 reverse transcriptase inhibitor.Isothermal titration calorimetry and molecular docking studies indicated that compound 3c may also function as a natural activator of protein kinase C(PKC).Therefore,compound 3c emerges as a potential candidate for developing new anti-HIV drugs.