INVESTIGATION OF CHEMICAL CONSTITUENT FROM CELASTRUS ANGULATUS

Three new β-dihydroagarofuran sesquiterpene polyol esters,one alkaloid andtwo non-alkaloids,were isolated from the MeOH extract of seed oil of Celastrus angulatus.Their structures were elucidated on the basis of UV,IR,mass,NOE difference,~1H-NMR,~(13)C-NMR and ~1H-~(13)C long-range correlation spectroscopy.     

2′,3′-乙氧甲撑基腺苷5′-硫代磷酰氨基酸酯的合成和谱学分析

核苷磷酰氨基酸酯化合物是一类倍受重视的药物 ,特别是它可作为寡聚核苷酸的类似物用于反义药物 [1] .HIV逆转录酶是治疗艾滋病的有效靶点 ,目前普遍使用的抗 HIV核苷类似物中 ,2′,3′-双脱氧核苷 (dd Ns)具有良好的疗效 [2 ] .苯氧基取代的核苷 -磷酰氨基酸酯是 HIV逆转录酶的有效抑制剂[3 ] ,其药物毒性比 dd Ns低 ,但容易在体内被核酸酶水解 .由于硫代磷酸对核酸酶具有抵抗性 ,它可以抑制核酸酶对它的水解 [4 ] ,因此我们设计合成了核苷 5′-硫代磷酰氨基酸酯化合物 ,希望开发出一种全新的 HIV逆转录酶抑制剂 .由于分子中引入氨基…     

Are the pyrazolines formed from the reaction of [60]fullerene with alkyl diazoacetates unstable?

[60]Fullerene-fused pyrazolines 1 were prepared by the reaction of C₆₀ with alky diazoacetates under the solid-state high-speed vibration milling conditions as well as in toluene solution. Pyrazolines 1 were stable in refluxing toluene and its thermolysis process in 1,2-dichlorobenzene was investigated, the decomposition rates and activation energies of pyrazolines 1 were obtained. The current work demonstrated that the liquid-phase reaction of C₆₀ with alkyl diazoacetates undergoes via 1,3-dipolar cycloaddition pathway at room temperature, or proceeds via carbene mechanism at a temperature of refluxing toluene, thus clarifies the previous ambiguity of its reaction mechanism.     

Synthesis of 2-Aminochromene Derivatives Catalyzed by KF／Al2O3

A series of 2-aminochromene derivatives including 2-amino-ben-zo[ h ] chromene, 2-amino-benzo [ f ] chromene and 2-amino-pyrano [3,2-h ]quinolin derivatives was synthesized from aryl-aldehyde, malononitrile or ethyl cyanoacetate and 1-naphthol or 2-naphthoi or 8-hydroxyquinoline in refluxing ethyl alcohol cat-alyzed by KF-Al2O3. The structures were confirmed by X-ray analysis.     

2-氨基-3-氰基-4-(4-氟苯基)-4H-苯并[h]苯并吡喃的合成和晶体结构

标题化合物与N,N-二甲基甲酰胺(DMF)形成的1:1混合结晶物C20H23FN2OC3H7NO由对氟苯甲醛、丙二腈、-萘酚在六氢吡啶存在下合成并经DMF与水的混合溶剂重结晶而得, 其结构通过元素分析、IR 和1H NMR对化合物进行了表征,用X-射线单晶衍射法测定了该化合物的晶体结构。结果表明,晶体属于单斜晶系,P21/n空间群,a = 6.365(1), b = 10.620(2), c = 29.122(6) ? b = 92.00(1), V = 1967.3(6) ?, Mr = 389.42, Z = 4, Dc = 1.315 g/cm3, m (MoKa) = 0.092 mm-1, F(000) = 816。晶体结构用直接法解出,经全矩阵最小二乘法修正,最终偏离因子R = 0.047, wR = 0.1053。化合物分子中,原子C(1), C(2), C(3), C(4), C(5) 和O(1)形成1个六员环,该六员环中C(1)C(2)键长为1.346(3) 牛砻魑肆被肺焦瓜蟆?     

球磨-溶剂热诱导法合成WS2纳米棒及其摩擦性能

采用行星式高能球磨机，将WS₂与S粉末混合球磨，得到纳米片状结构的前驱体，然后添加分散剂聚乙二醇(PEG)用溶剂热诱导的方法使纳米片状前驱体发生结构转变，制备了棒状结构的WS₂纳米材料。用XRD、SEM、TEM等方法对WS₂纳米棒进行了形貌和结构表征，并对其作为润滑油添加剂的摩擦性能进行了初步的研究。     

Nb 掺杂LiFePO4/C 的一步固相合成及电化学性能

用固相法一步合成了Nb掺杂的LiFePO4/C复合材料, 研究了Nb掺杂量对材料电化学性能的影响. 结果表明, Nb掺杂后LiFePO4/C复合材料的电化学性能明显提高. 在0.5C、1C和2C充放电倍率下, 名义成分为Li0.96Nb0.008FePO4/C正极材料的比容量分别为161、148和132 mAh•g−1, 已达到实用化水平. 阻抗谱和循环伏安特性测试显示, Nb掺杂有效地降低了复合材料电极的阻抗和极化, 说明Nb掺杂的主要作用是提高了LiFePO4的电子电导率.     

3-苯基-1-丁炔-3-醇质谱碎裂中[C8H7]^+的结构及分子内质子迁移反应

报道了3-苯基-1-丁炔-3-醇的常规电子轰击质谱(EIMS)。利用碰撞诱导解离(CID)技术研究了质谱碎裂过程中产生的[C8H7]^+的气相离子结构。同时, 氘代同位素交换、亚稳(MI)和CID实验进一步证实了m/z 103离子的形成并不是分子离子的质谱碎裂中顺次失去甲基自由基和中性CO分子的直接氢迁移的协同反应, 而是在失去CO分子前后发生了二次质子迁移反应的逐步过程。在此基础上提出了一种独特的双分子质子键合复合物中间体的碎裂机理。     

γ-Fe2O3纳米粉的低热固相制备及其电磁损耗特性(英)

The Fe(OH)₃ precursor was prepared by solid -state reaction with Fe(NO₃)₃·9H₂O, NaOH and dispersed poly-ethylene glycol at low heating temperature(25 ℃). Synthesis of iron oxide (γ-Fe₂O₃) nanoparticle was achieved by thermal decomposition of Fe(OH)₃·xH₂O precursor. The nanoparticle was characterized by TG-DTA, X-ray diffra-ction, TEM etc. The results showed that the nanoparticle was composed of γ-Fe₂O₃ and was a better absorber for electromagnetic wave within the low frequency band.     

Ru_n(n=2~8)金属团簇的结构和能级分布的DFT研究

采用密度泛函理论中的广义梯度近似(DFT/GGA)方法,对Run团簇(n = 2~8)的几何结构与稳定性、束缚能以及能级分布的关系进行了研究,并分析了随着团簇原子数的增加,团簇的几何结构和费米能级的变化,结果表明:Ru簇的几何结构在4个原子以前是平面结构,而从5个原子开始为空间立体的稳定结构,束缚能随金属原子数的增加而增加。能级结构呈明显的分立特征,费米能级随原子个数的增加而增加,但从Ru7开始又有所降低,且团簇的能量间隙逐渐减小,趋近于大块金属的能级特征。