摘要:

AbstractCyclopalladated ferrocenylimine has been found to be a type of excellent phosphine‐free catalyst for Heck reactions in neat water with both higher yields and turnover numbers than those reported in the literature up to now. Some commercial emulsifying agents, including the commonly used quaternary ammonium salts, have been proved to be excellent additives in the catalysis of the reactions. Not only aromatic iodide, but also aromatic bromide could be coupled with the olefins. All reactions were able to be conducted in air under refluxing conditio

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210702

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

Abstract8,8‐Dimethyl‐5,6,7,8‐tetrahydrophenanthrene‐3,4‐dione (3) and 8,8‐dimethyl‐2‐(l‐hydroxy ethyl)‐5,6,7,8‐tetrahydrophenanthrene‐3,4‐dione (4), two analogues of the antitumor active tanshinone, were synthesized from anisole. The synthesized compounds 3 and 4 were shown to be highly active against leukemia P‐388 cell line as a

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210703

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractA flexible approach to ethyl (3R.4S)‐N‐Boc‐4‐amino‐3‐hydroxy‐S‐phenylpentanoate (N‐Boc‐AHPPA‐OEt), the γ‐aminoβ‐hydroxy add moiety of hapalosin is described. The synthetic method features a ring‐opening ethanolysis of an activatedN‐Boc‐lactam, which is obtained via a diastereoselective reductive‐alkylation of (R)‐malimide derivative. The flexibility of the method resides in the introduction of the alkyl side chain by Grignard reagent addition.Project supported by the National Science Foundation for Distinguished Young Investigators, the National Natural Science Foundation of China and the Fund for doctor

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210704

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractA new type of dendritic NOBIN derived Schiff base ligands has been synthesized and applied to titanium catalyzed hetero‐Diels‐Alder reaction of Danishelfsky's diene and aldehydes, affording the corresponding 2‐substituted 2,3‐dihydro‐4H‐pyran‐4‐one in good yields and moderate enantioselectivities (up to 59.2%ee). It was found that the size of dendron attached to the tri‐dentated ligands has slight impact on the enantioselectivity of the reaction and the second generation of dendritic ligand exhibited the best e

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210705

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractPhosphatidylcholines and their analogs, the functional building block of the membrane, are recently found to mediate multiple physiological processes and exhibit a broad range of desirable pharmacological effects, which involve hydrophobic lipophilic interactions (HLI) between the phospholipid and the cell membrane. The HLI behavior of phosphatidylcholines (Ln) and their analogues 1, 2‐diacyl‐sn‐glycerol‐3‐phosphoric acid bromoethyl ester (Pn), have been investigated in MeOH‐H2O binary systems of different volume fractions (designated as ϕ) of the organic component, by employing α‐nephthylethyl lauryl ether (Np‐12) as fluorescent probe. A very interesting observation is that the Lnpossesses double character,i.e., it behaves both as an aggregator and as a deaggregator. The effects of the structure and the environment on the coaggregation and deaggregation a

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210706

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractOne linear template 13 and one cyclophane template 15, both incorporating two electron rich 1,4‐dialkoxybenzene units and one diamide unit, have been synthesized. By utilizing donor‐acceptor interaction and/or intermolecular hydrogen bonding assembling principles, one novel hetero[3]rotazane 22·4Cl, possessing one neutral and one tetracationic ring components, has been synthesized from 13, through neutral [2]rotaxane 21 as intermediate. With 15 as template, tetracationic [2]catenane 23·4PF6was assembled by using donor‐acceptor interaction, but no neutral [2]rotaxane could be obtained under the typical conditions of hydrogen bonding assembling principle. The interlocked supramolecular compounds have been characterized and their spectral properties are inves

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210707

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractThe reaction system of diperoxooxalatovanadate {K3[VO(O2)2‐(C2O4)]·H2O, bpV(Oxa)} and imidazole was studied in an aqueous solution by ID multinuclear (1H,13C and51V) NMR, 2D NMR diffusion ordered spectroscopy (DOSY), and variable temperature NMR techniques. It was shown that DOSY was a useful tool for the study of a mixture. All of the1H and13C NMR signals of the peroxovanadate (V) complexes were assigned. The NMR experimental results indicated that a new complex was formed through the coordination interactions between bpV(Oxa) and imidazole. The newly‐formed complex is stable under the experimental condition. Electrospray ionization mass spectrometry (ESI‐MS) provides positive evidence to support the conc

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210708

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractThe molecular recognition behavior of the chiral salen‐metal complexes towards guest molecules, such as imidazole derivatives and amino‐acid ester, was systematically investigated by means of circular dichroism (CD) spectra. The coordination numbers of the host‐guest complexes as well as the recognition capability of the salen‐metal complexes were explained by character and intensity analyses of the CD

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210709

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractA synthetic cationic surfactant, 5,5‐ditetradecyl‐2‐(2‐trimethyl‐ammonioethyl)‐1,3‐dioxane bromide (DTDB), was used to construct a supported bilayer lipid membrane (s‐BLM) coated on an underlying glassy carbon electrode (GCE). Electrochemical impedance spectroscopy (EIS), small‐angle X‐ray diffraction (SAXD) and cyclic voltammetry were used to characterize the s‐BLM. Both EIS and SAXD data indicated that the synthetic lipid exists as a well‐oriented bilayer in the membrane. The voltammetric study showed that the lipid membrane can open ion channels in the presence of ClO4−stimulant with Ru(bpy)2/3+as marker ions and give distinct channel currents. The channels can be closed and open up again many times by removing o

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210710

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY

摘要:

AbstractFe3O4particles coated with acrylic copolymer (ACP) of about 5–8 nm in diameter were synthesized and used for immobilization of horseradish peroxidase (HRP). Direct electrochemistry of HRP embedded in the nanosized Fe3O4solid matrix modified paraffin impregnated graphite electrode (PIGE) was achieved, which is related to the heme Fe(III)/Fe(II) conversion of HRP. Cyclic voltammetry gave a pair of reproducible and well‐defined redox peaks at aboutEmof‐0.295 V vs. SCE. The standard rate constantk2was determined as 2.7 s−1. It demonstrated that the nano‐Fe3O4solid matrix offers a friendly platform to assemble the HRP protein molecules and enhance the electron transfer rate between the HRP and the electrode. UV‐Vis absorption spectra and FTIR spectra studies revealed that the embedded HRP retained its native‐like structure. The HRP/Fe3O4/PIGE showed a strong catalytic activity toward H2O2. The voltammetric response was a linear function of H2O2concentration in the range of 10–140 μmol/L with detection limit of 7.3 μmol/L (s/n= 3). The apparent Michaelis‐Menten constant is calculate

ISSN:1001-604X    

DOI:10.1002/cjoc.20030210711

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:2003

数据来源: WILEY