粤北产五味子科植物风沙藤的化学成分研究Ⅰ.

从粤北产五味子科植物风沙藤(Schisandra viridis A.C.Sm.)的根和茎中,分到三个新的联苯环辛二烯木脂素化合物,它们的结构和构型通过光谱分析和化学转变得以证实,并分别命名为:五脂酮(Schisanlignone)C(1),D(2)和五脂醇(schisan-lignaol)D(3)。     

粤北产五味子科植物风沙藤的化学成分研究(II)

本文继续报道从粤北所采集的五味子科植物风沙藤(Schisandra viridis A. C.Sm)根和茎中分得的另外三个木脂素类新化合物, 即五味子酯(schisantherin)K,五脂酮(Schisanlignone)E和异安五脂素(isoanwulignan)。通过光谱分析和化学转变, 确定了它们的结构和构型。     

粤北产五味子科植物风沙藤的化学成分研究(II)

本文继续报道从粤北所采集的五味子科植物风沙藤(Schisandra viridis A. C.Sm)根和茎中分得的另外三个木脂素类新化合物, 即五味子酯(schisantherin)K,五脂酮(Schisanlignone)E和异安五脂素(isoanwulignan)。通过光谱分析和化学转变, 确定了它们的结构和构型。     

甘油糖脂的合成 Ⅰ.1,2-二-O-脂酰基-3-O-(α-D-吡喃半乳糖基)-sn-甘油的合成

采用一种有效的方法合成了具有不同链长的二脂酰基α D 半乳糖型甘油糖脂 .将半乳糖烯丙苷化 ,重结晶得到α D 半乳糖烯丙苷 .随后将糖环的羟基用苄基保护 ,再利用OsO4 /NMO(N 甲基 N 氧吗啉 )的二羟基化条件将 1 O烯丙基氧化成为邻二羟基 ,得到 3 O ( 2′ ,3′ ,4′ ,6′ 四 O 苄基 α D 吡喃半乳糖基 ) sn 甘油 .其与不同链长的脂酰氯进行脂酰化反应 ,然后氢解去掉苄基得到五种二脂酰基α D 半乳糖苷基甘油 .利用1HNMR ,13 CNMR ,2DNMR ,IR和MS对化合物的结构进行了确证 .     

甘油糖脂的合成工.1,2-二-O-脂酰基-3-O-(α-D-吡喃半乳糖基)-sn-甘油的合成

采用一种有效的方法合成了具有不同链长的二脂酰基α-D-半乳糖型甘油糖脂.将半乳糖烯丙苷化,重结晶得到α-D-半乳糖烯丙苷.随后将糖环的羟基用苄基保护,再利用OsO4/NMO(N-甲基-N-氧吗啉)的二羟基化条件将1-O烯丙基氧化成为邻二羟基,得到3-O-(2＇,3＇,4＇,6＇-四-O-苄基-α-D-吡喃半乳糖基)-sn-甘油.其与不同链长的脂酰氯进行脂酰化反应,然后氢解去掉苄基得到五种二脂酰基α-D-半乳糖苷基甘油.利用1H NMR,13C NMR,2D NMR,IR和MS对化合物的结构进行了确证.     

粤北产五味子科植物风沙藤的化学成分研究(Ⅱ)

本文继续报道从粤北所采集的五味子科植物风沙藤(Schisandra viridis A.C Sm)的根和茎中分得的另外三个木脂素类新化合物,即五味子酯(schisantherin)K(1),五脂酮(schisanlignone)E(2)和异安五脂素(isoanwulignan)(3)。通过光谱分析和化学转变,确定了它们的结构和构型。     

富勒烯C70及Sc3N@C70的密度泛函理论研究

在混合密度泛函B3LYP理论下,用6-31G*基函数对富勒烯C70、它的阴离子及内掺Sc3N富勒烯Sc3N@C70两种同分异构体的几何结构和电子结构进行了研究。计算结果表明,在C70的两种异构体中,满足五元环分离规则(IPR)的C70(D5h)稳定,C70q-(#7854)(q=4,6)比C70q-(D5h)稳定;在Sc3N@C70两种异构体中有三对两两相邻五元环的Sc3N@C70(#7854)稳定,C70(#7854)易于形成富勒烯金属包合物。     

翼梗五味子的研究 V: 五脂素A1, A2, 表五脂A1和epischisandrone的结构

从四川宜宾产翼梗五味子的果实中分得七个四氢萘木脂素, 其中三个鉴定为: 恩施辛enshicine, 表恩施辛epienshicine和schisandrone, 其余四个均属新化合物, 命名为五脂素wnlignan A1, 五脂素A2, 表五脂素epiwnlignan A1和epischisandrone. 它们的结构(包括绝对构型)由光谱分析和化学转化为(+)-dimethylguaiacine和(-)-dimethylisoguaiacine而阐明. 四个新化合物皆有不同程度的体外抗癌活性.     

C78n离子的Jahn-Teller畸变和电子光谱

用INDO系列方法对C78n(D3、D3h、D?h)进行系统研究,表明C78(D3)比C78(D3h、D?h)稳定,与理论计算及实验结果一致;且随n绝对值增大,C78n总能量升高;C78n(D3、D3h、D?h)异构体的部分离子发生了Jahn-Teller畸变.以优化构型为基础,用INDO/SCI方法首次计算了C78n的电子光谱,对电子跃迁进行理论指认,讨论C78n光谱的特征吸收与C78相比发生红移的原因.     

甘油糖脂的合成I.1,2-二－O－脂酰基－3－O－（α-D-吡喃半乳糖基）－sn-甘油的合成

采用一种有效的方法合成了具有不同链长的二脂酰基α-D-半乳糖型甘油糖脂 。将半乳糖烯丙苷化，重结晶得到α－D－半乳糖烯丙苷。随后将糖环的羟基用苄 基保护，再利用OsO4/NMO(N-甲基－N－氧吗啉）的二羟基化条件将1－O烯丙基氧化 成为邻二羟基，得到3－O－（2′，3′，4′，6′－四－O－苄基－α－D－吡喃半 乳糖基）－sn-甘油。其与不同链长的脂酰氯进行脂酰化反应，然后氢解去掉苄基 得到五种二脂酰基α-D-半乳糖苷基甘油。利用^1H NMR,^13C NMR,2D NMR,IR和MS 对化合物的结构进行了确证。     

中国乌头的研究:XXIII, 紫草乌生物碱的研究

从云南紫草乌(Aconitum delavayi Franch)中又分得四个生物碱, 其中三个为新的二萜类生物碱, 分别命为紫草乌碱丙(delavaconitine C,3),紫草乌碱丁(delavaconitine D,5)和紫草乌碱戊(delavaconitime E,6),经乙酰 化、水解及UV、IR、MS、^1H和^1^3CNMR 的测定, 确定了它们的化学结构。另一个经鉴定为紫草乌碱甲胺醇(delavaconine, 2), 首次从植物中分离得到。     

罗汉松科植物中化学成分的研究:I.竹柏中的抗肿瘤成分

从罗汉松科植物竹柏(Podocarpus nagi(thunb.)Zoll.ct Mor.ex Zoll.)种子中分得七种成分。根据理化性质、波谱数据及化学反应鉴定为竹柏内酯A(1)、1-去氧-2α-羟基竹柏内酯A(3)、竹柏内酯苷A(4)、柳杉酚(5)、β-谷甾醇及蔗糖, 其中4是新化合物, 5是首次从该植物中分得。生物试验表明, 二萜双内酯化合物1-3具有较强的细胞毒作用, 4 无效。对2及3进行了结构改造, 提示了它们的构效关系。     

Electron and nuclear dynamics of molecular clusters in ultraintense laser fields. III. Coulomb explosion of deuterium clusters

In this paper we present a theoretical and computational study of the energetics and temporal dynamics of Coulomb explosion of molecular clusters of deuterium (D2)n/2 (n = 480 - 7.6 x 10(4), cluster radius R0 = 13.1 - 70 A) in ultraintense laser fields (laser peak intensity I = 10(15) - 10(20)W cm(-2)). The energetics of Coulomb explosion was inferred from the dependence of the maximal energy EM and the average energy Eav of the product D+ ions on the laser intensity, the laser pulse shape, the cluster radius, and the laser frequency. Electron dynamics of outer cluster ionization and nuclear dynamics of Coulomb explosion were investigated by molecular dynamics simulations. Several distinct laser pulse shape envelopes, involving a rectangular field, a Gaussian field, and a truncated Gaussian field, were employed to determine the validity range of the cluster vertical ionization (CVI) approximation. The CVI predicts that Eav, EM proportional to R0(2) and that the energy distribution is P(E) proportional to E1/2. For a rectangular laser pulse the CVI conditions are satisfied when complete outer ionization is obtained, with the outer ionization time toi being shorter than both the pulse width and the cluster radius doubling time tau2. By increasing toi, due to the increase of R0 or the decrease of I, we have shown that the deviation of Eav from the corresponding CVI value (Eav(CVI)) is (Eav(CVI) - Eav)/Eav(CVI) approximately (toi/2.91tau2)2. The Gaussian pulses trigger outer ionization induced by adiabatic following of the laser field and of the cluster size, providing a pseudo-CVI behavior at sufficiently large laser fields. The energetics manifest the existence of a finite range of CVI size dependence, with the validity range for the applicability of the CVI being R0 < or = (R0)I, with (R0)I representing an intensity dependent boundary radius. Relating electron dynamics of outer ionization to nuclear dynamics for Coulomb explosion induced by a Gaussian pulse, the boundary radius (R0)I and the corresponding ion average energy (Eav)I were inferred from simulations and described in terms of an electrostatic model. Two independent estimates of (R0)I, which involve the cluster size where the CVI relation breaks down and the cluster size for the attainment of complete outer ionization, are in good agreement with each other, as well as with the electrostatic model for cluster barrier suppression. The relation (Eav)I proportional to (R0)I(2) provides the validity range of the pseudo-CVI domain for the cluster sizes and laser intensities, where the energetics of D+ ions produced by Coulomb explosion of (D)n clusters is optimized. The currently available experimental data [Madison et al., Phys. Plasmas 11, 1 (2004)] for the energetics of Coulomb explosion of (D)n clusters (Eav = 5 - 7 keV at I = 2 x 10(18) W cm(-2)), together with our simulation data, lead to the estimates of R0 = 51 - 60 A, which exceed the experimental estimate of R0 = 45 A. The predicted anisotropy of the D+ ion energies in the Coulomb explosion at I = 10(18) W cm(-2) is in accord with experiment. We also explored the laser frequency dependence of the energetics of Coulomb explosion in the range nu = 0.1 - 2.1 fs(-1) (lambda = 3000 - 140 nm), which can be rationalized in terms of the electrostatic model.     

内南五味子化学成分的研究

从内南五味子的茎藤中分得七个化合物, 经波谱和X衍射分析, 其中五广系一类新型的螺环衍生物木脂素, 分别定名为内南五味子素(3), 内南五味子素乙(4), 丙(5),J(6)及异内南五味子素(7), 另外两个已知化合物为南五味子素和β-谷甾醇。     

Study on the bile salt, sodium scymnol sulfate, from Rhizoprionodon acutus. II. The structures of scymnol, anhydroscymnol and sodium scymnol sulfate.

The crystal structures of anhydroscymnol (I) and scymnol (II), which were prepared from sodium scymnol sulfate (III) isolated from the bile of Rhizoprionodon acutus, have been determined by means of X-ray diffraction analyses. The crystals of I are orthorhombic, space group P2(1)2(1)2(1) with Z = 4; unit-cell dimensions: a = 13.562(2), b = 21.636(2), c = 8.735(2) A; II orthorhombic, space group P2(1)2(1)2, with Z = 4; unit-cell dimensions a = 18.553(2), b = 19.887(2), c = 7.986(2) A. Both structures, (24R,25S)-(+)-24,26-epoxy-5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol (I) and (24R)-(+)-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,26,27-hexol (II), were solved from diffractometric data by direct methods and refined by least-squares calculations to R = 0.073 (I) and R = 0.062 (II) (2044 (I) and 2250 (II) observed independent significant reflections (I greater than 3 sigma(I)), respectively. All the hydroxyl groups of both compounds are involved in a hydrogen-bonding network. The structure of III was determined to be (24R,25S)-(+)-3 alpha,7 alpha,12 alpha,24,26-pentahydroxy-5 beta-cholestan-27-yl sodium sulfate, based on the chemical data that alkaline degradation of III with aqueous potassium hydroxide gives only I.     

Ca3Pt(4+x)Ge(13-y) and Yb3Pt4Ge13: new derivatives of the Pr3Rh4Sn13 structure type

The new phases Ca(3)Pt(4+x)Ge(13-y) (x = 0.1; y = 0.4; space group I2(1)3; a = 18.0578(1) ?; R(I) = 0.063; R(P) = 0.083) and Yb(3)Pt(4)Ge(13) (space group P4(2)cm; a = 12.7479(1) ?; c = 9.0009(1) ?; R(I) = 0.061, R(P) = 0.117) are obtained by high-pressure, high-temperature synthesis and crystallize in new distortion variants of the Pr(3)Rh(4)Sn(13) type. Yb(3)Pt(4)Ge(13) features Yb in a temperature-independent non-magnetic 4f(14) (Yb(2+)) configuration validated by X-ray absorption spectra and resonant inelastic X-ray scattering data. Ca(3)Pt(4+x)Ge(13-y) is diamagnetic (χ(0) = -5.05 × 10(-6) emu mol(-1)). The Sommerfeld coefficient γ = 4.4 mJ mol(-1) K(-2) for Ca(3)Pt(4+x)Ge(13-y), indicates metallic properties with a low density of states at the Fermi level in good agreement with electronic structure calculation (N(E(F)) = 3.3 eV(-1)/f.u.)); the Debye temperature (θ(D)) is 398 K.     

甾体植物生长激素合成的研究IV.一些中间体的合成

Steroidal plant growth hormone intermediates, I (R = H, Ac; R1 = MeC:CHMe, MeCHCOMe, MeCHQ, MeCHQ1) were prepared from hydrodeoxycholic acid (I, R = H, R1 = MeCHCH2CH2CO2H).     

New structural types and different oxidation levels in the family of Mn6-oxime single-molecule magnets

The synthesis and magnetic properties of three new members of a family of salicyaldoxime based [Mn6] single-molecule magnets possessing new structural types, core topologies and Mn oxidation state distributions are reported. The isostructural complexes [MnIII6O2(R-sao)6(X)2(EtOH)6] (R = Et, X = Br (1); R = Me, X = I (2)) exhibit single-molecule magnet behaviour with spin Hamiltonian parameters S = 12, g = 1.98 and D = -0.36 cm(-1) in both cases. The hexametallic cluster [MnIII4MnIV2O2(OMe)(4-)(Et-sao)6(MeOH)2].MeOH (3.MeOH) possesses a planar rod-like topology and a mixed valent [MnIV4MnIII2] core, which is unprecedented in this family of [Mn6] SMMs.     

合理利用甾体皂苷元资源的研究 I: 具有油菜甾醇内酯A/B环结构单元的甾体皂苷元的合成

本文提出用薯蓣皂苷元合成油菜甾醇内酯及其类似物的新思想, 从薯蓣皂苷元合成了具有油菜甾醇内酯A/B环结构单元的新甾体皂苷元。作为进一步合成油菜甾醇内酯的重要中间体, 它本身也显示促进植物生长的作用。     

猪去氧胆酸化学 8:锇催化不对称双羟化合成 (24R,25R)-24,25,26-三羟基胆固醇

本文报道应用锇催化不对称双羟化对甾体化合物侧链三取代双键的反应合成得光学纯3a和3b,(3a:3b=6.5:1),收率分别为71%和11%.从3a经五步反应合成新的维生素D~3类似物的关键中间体(24R,25R)-24,25,26-三羟基胆固醇(10).