Studies on Chem icalCom position ofIron-m olybdenum Cofactor fromNitrogenase by Fluorescence Analysis

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A New Rearrangement Reaction of 2-Phenyl Substituted Benzothiazepine with Ethoxycarbonyl Carbene─Mechanism of the Reaction and Structure of the Product

Intheprevi0usaFticlesl-2wehavereportedthatthereacti0n0fbenz0diazepinewithethoxycarbonylcarbenemayobtainnormal[2 l]cycIoadditi0npr0ductsregardlessthe2-substitUentismethyl0rphenyl.Howeverunderthesamec0nditi0nsthereaction0fbenzothiazepinewithethoxycarbonylcarbeneunderwentrearrangementreacti0n.Forexample,whenthe2-substituentismethyl,thereacti0nofbenzothiazepinewithethoxycarbonylcarbenegivearing-openingproductIIatroomorhightemperature'.Whenthe2-substituentisphenyl,weunexpectedlyfoundan0thernewrea…     

A New Lignan Glucoside from Lancea tibetica

L.tibeticaHook.f.etThorns.isanimportantTibetanmedicineusedfortreatmentofmanydiseases'.Thelignanglycosidesandtriterpenesfromthisplanthavebeenreported"'byHuidiZhangetal.ThispaperdescribesthestructureelucidationofanewIignanglucoside,namedtibeticosideA1...     

阴离子型芘基探针用于水体中对硝基苯胺的荧光检测

本研究利用阴离子型芘衍生物8-羟基芘-1,3,6-三磺酸三钠盐(HPTS),建立了一种快速、可视化的对硝基苯胺(PNA)荧光检测方法.检测原理主要是基于PNA通过非共价作用而导致的HPTS的荧光淬灭.通过测量加入PNA后HPTS在512 nm处荧光强度的变化,可以实现PNA的荧光检测.本方法的线性范围为10~120μmol/L,检出限(3σ/s)为4.6μmol/L.对本方法的抗干扰性以及方法的实际应用性进行了考察.结果表明,本方法具有低成本、高灵敏度、高选择性、操作简便等优点.     

Structure Evolution upon Uniaxial Drawing Skin‐ and Core‐Layers of Injection‐Molded Isotactic Polypropylene by In Situ Synchrotron X‐ray Scattering

The structure evolution of the oriented layer (skin) and unoriented layer (core) from injection‐molded isotactic polypropylene samples upon uniaxial drawing is probed by in situ synchrotron X‐ray scattering. The X‐ray data analysis approach, called “halo method”, is used to semiquantitatively identify the transformation process of crystal phase upon uniaxial drawing. The results verify the validation of the stress‐induced crystal fragmentation and recrystallization process in the deformation of the injection‐molded samples under different temperatures. Furthermore, the end of strain softening region in the engineering stress‐strain curves explicitly corresponds to the transition point from the stress‐induced crystal fragmentation to recrystallization process. Basically, the skin and core layers of the injection‐molded parts share the similar deformation mechanism as aforementioned. The stretching temperature which dramatically affects the relative strength between the entanglement‐induced tie chains and the adjacent crystalline lamellae determines the crystal structural evolution upon drawing. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1618–1631     

Terpenoids from Roots of Chloranthus spicatus

Five new terpenoids, including four eudesmane‐type sesquiterpenoids, 1 – 4 , and one labdane‐type diterpenoid, 6 , together with ten known compounds, were isolated from the roots of Chloranthus spicatus. The structures and their relative configurations were mainly established by 1D‐ and 2D‐NMR spectra, and MS experiments.     

Biologically Active Iridoids from Hedyotis diffusa

Two new iridoids, 10‐O‐benzoyl‐6′‐O‐α‐L ‐arabino(1→6)‐β‐D ‐glucopyranosylgeniposidic acid ( 1 ), deacetyl‐6‐ethoxyasperulosidic acid methyl ester ( 2 ), along with 14 other known iridoids, were isolated from the whole plant of Hedyotis diffusa Willd. Their structures were determined on the basis of spectroscopic analysis. The short‐term‐memory‐enhancement activities of compounds 1, 7 – 9, 11 , and 13 were evaluated on an Aβ transgenic drosophila model.     

Supramolecular networks of 10‐(2‐hydroxyethyl)acridin‐9(10H)‐one and 10‐(2‐chloroethyl)acridin‐9(10H)‐one

Both 10‐(2‐hydroxyethyl)acridin‐9(10H)‐one, C₁₅H₁₃NO₂, and 10‐(2‐chloroethyl)acridin‐9(10H)‐one, C₁₅H₁₂ClNO, have monoclinic (P2₁/c) symmetry and supramolecular three‐dimensional networks. But the differences in the intermolecular interactions displayed by the hydroxy group and the chlorine substituent lead to stronger intermolecular π‐stacking interactions and hydrogen bonding, and hence a significantly higher melting point for the former.