Structural Study on NMR and X-Ray of Lactucopicrin—A Guaianolide Ester

The guaianolide ester is a potent inhibitor of cancer cells. Lactucopicrin, a guaianolide, shows analgesic, antitussic, and sedative activities. In order to investigate its structure, ¹H and ¹³C NMR and 2D NMR have been carried out at a proton field strength of 400 MHz and a carbon field strength of 100 Mhz in DMSO-d ₆ at 20°C. Resonances for all protons and carbons have been assigned. The results of HMQC and HMBC experiments suggest that the structure of lactucopicrin is as shown in Fig. 1. Its stereostructure is verified by the X-ray experiment. ¹H and ¹³C NMR of lactucopicrin are reported. Its 2D NMR and X-ray are reported for the first time.     

A facile electrochemical synthesis of caffeic acid derivatives in the presence of acetylacetone or methyl acetoacetate in aqueous medium

The anodic oxidation of caffeic acid in the presence of acetylacetone or methyl acetoacetate in aqueous solution has been studied by cyclic voltammetry and controlled-potential electrolysis techniques. The result showed that caffeic acid was oxidized to the corresponding o-benzoquinone, which underwent further Michael-addition with acetylacetone or methyl acetoacetate to produce caffeic acid derivative 3,4-dihydroxy-6-(1-acetylacetone)-yl cinnamic acid 4a or 3,4-dihydroxy-6-(1-acetyl-methylacetate)-yl cinnamic acid 4b.     

Surface-enhanced Raman spectra study of metal complexes of N-D-glucosamine beta-naphthaldehyde and glycine and their interaction with DNA

Copper(II), zinc(II), cobalt(II) and cobalt(III) complexes of N-D-glucosamine beta-naphthaldehyde (C17H19O6N, NG) and glycine were synthesized. The four novel metal complexes, Cu(II)C19H28O11N2(CuGNG), Zn(II)C19H24O9N2 (ZnGNG), Co(II)C19H28O11N2(Co(II)GNG) and Co(III)C21H29O12N2(Co(III)GNG) were characterized by means of infrared (IR), electronic absorption spectroscopy and NMR etc. The surface-enhanced Raman spectra of the four complexes and their interaction with DNA were studied. By comparison of the surface-enhanced Raman spectra (SERS), the information of the four complexes' SER active sites and adsorption orientation were obtained. Combined with fluorescence spectra of Ethidium bromide (EthBr) DNA system, we concluded that none of the four complexes intercalate into DNA and that the presence of the glycine ligand lowered the anticancer activity of NG series complexes.     

The in vivo neutron activation analysis of calcium in the skeleton of normal subjects,with hypokinesia and bone diseases

A facility developed for the in-vivo neutron activation analysis (IVNAA) of calcium in some parts of tubular limb bones, in the hand, foot and spine is described. The⁴⁸Ca(n, )⁴⁹Ca reaction is used, the gamma-rays of⁴⁹Ca (E=3.08 MeV, T_1/2=8.8 min) are measured. The irradiation is carried out with five of ten²³⁸Pu–Be neutron sources with a source stength of 5·10⁷ n s^–1 each arranged in a bath filled with water. NaI(T1) detectors (from 2 to 4 in number) of 150×100 mm size supplied with lead and shadow shielding are used in the counting unit. The construction of the facility started in 1972 and has been in operation since 1974. It has been used for the examination of patients suffering from limb bone tumors, of children with rickets-like and similar diseases and for studies in space medicine.     

Cu（I）/Diamine-catalyzed Aryl-alkyne Coupling Reactions

Arylalkynes are important building blocks for the synthesis of natural products,pharmaceuticals,and artificial molecular devices1.They are often synthesized via the Pd-catalyzed Sonogashira coupling reactions between aryl halides and terminal alkynes2,3.Unfortunately,it remains difficult to apply the Sonogashira reaction to industrial scale and/or pharmaceutical synthesis,due to the high cost of Pd and the difficulty in removing the toxic Pd residues from the reaction products.Thus it is wor…     

Study of Structures and Electronic Properties of Pdn–1Pb and Pdn （n≤8） Clusters

Geometric and electronic properties of Pdn–1Pb and Pdn (n≤8) clusters have been studied by using density functional theory with effective core potentials, focusing on the differences between mono- and bimetallic clusters. The average bond length of Pdn–1Pb (n≤8) bimetallic clusters is longer than that of pure palladium clusters except for n = 2 and 3. The most stable structure of Pdn–1Pb (n≤7) is the singlet where there is at least a Pd or Pb atom on its excited state. The energy gaps of Pd–Pb binary clusters are narrower than those of Pdn clusters, and then the chemical activity is strengthened when Pdn clusters are doped with Pb.     

Template-free, polymerase-free DNA polymerization

A combination of a DNA ligase and a restriction endonuclease provides a DNA polymerase activity, which might suggest a novel strategy for polymer synthesis.     

岩石的核磁共振自旋密度微成像

岩，心是油气储层的基本单元，其内部结构和渗流性质反映了油藏的基本特征．岩。心的精细描述是油藏描述、储层动态监测及设计强化采油方案的重要基础．本文利用核磁共振（NMR）自旋密度做成像，快速无损地观测到两类基本储油岩石——砂岩和灰岩的内部结构，提供了岩石渗透性、孔隙性及灰岩沉积环境等重要信息．1实验方法以自旋回波单片NMR成像脉冲序列为基础，设。P平面内样品的目施密度为P（。，v）．演化期t。，在。方向梯度场G。作用下，各处横向磁化矢量获得的相移为式中，7为共振核（在成像中一般为质子）的旋磁比，g为坐标位置·…     

Nonalkaloid Constituents from Stemona japonica

Five new nonalkaloid constituents, a neolignan, japonin A ( 1 ), a macrocyclic lactone, japonin B ( 2 ), a (phenylethyl)benzoquinone, japonin C ( 3 ), a phenanthraquinone, japonin D ( 4 ), as well as a dihydrostilbene, stilbostemin M ( 5 ), were isolated from the roots of Stemona japonica, together with eight known compounds. Their structures were established by spectroscopic analyses.