摘要:

AbstractRecently, the demand for synthetic oxetanes has increased because the highly strained structure allows specific biologic functions in vivo and also serves unique purposes in industrial materials. This review article summarizes recent progress in regio‐, site‐, and stereo‐selective formation of oxetanes via a photochemical pr

ISSN:0009-4536    

DOI:10.1002/jccs.200800072

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractStable silabenzenes (1a;R = Tbt,1b;R = Bbt) were synthesized by taking advantage of extremely bulky and efficient steric protection groups, 2,4,6‐tris[bis(trimethylsilyl)methyl]phenyl (Tbt) and 2,6‐bis‐[bis(trimethylsilyl)methyl]‐4‐[tris(trimethylsilyl)methyl]phenyl (Bbt). The structure of Tbt‐substituted1awas determined by X‐ray crystallographic analysis, which demonstrated the complete delocalization of the π‐electrons of the silabenzene ring. It was found that silabenzene1areacted with C–C and C–O multiple bond compounds to give the corresponding [4+2]‐cycloadducts via 1,4‐addition, while1aunderwent both 1,2‐ and 1,4‐additions by the reaction with methanol. Silabenzene1adimerized very gradually to afford its [4+2]‐dimer, although1bshowed no change under the same conditions. Photochemical reaction of1agave the corresponding silabenzvalene isomer instead o

ISSN:0009-4536    

DOI:10.1002/jccs.200800073

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractCetyltrimethylammonium peroxodisulfate (CTA)2S2O8was quantitatively prepared and used for the deprotection of oximes, phenylhydrazones, semicarbazones and thiosemicarbazones to the corresponding carbonyl compounds in acetonitrile. Its agent is more efficient and has advantages over similar reagents in terms of the amount of oxidant, short reaction time, simple work up, and high yield.

ISSN:0009-4536    

DOI:10.1002/jccs.200800074

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractSubstituted acetophenone1in BMImPF6ionic liquid, heated at 120 °C for 24 h, produces β‐methylchalcone2, triarylbenzene3, and triarylpyrylium salt4.BMImPF6catalyzes the self‐aldol condensation of1, whose cyclotrimerization gives an increased conversion to4at the expense of3normally obtained from the cyclotrimerization of1in common organic so

ISSN:0009-4536    

DOI:10.1002/jccs.200800075

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractMagnolol, a pure compound extracted fromMagnolia officinalis, encapsulated by liposome was investigated for inhibiting vascular smooth muscle cell (VSMC) proliferation leading to restenosis by Percutaneous Transluminal Coronary Angioplasty (PTCA). 1,2‐Diacyl‐Sn‐glycero‐3‐phosphocholine (EPC) and 1,2‐dipalmitoyl‐Sn‐glycero‐3‐phosphocholine (DPPC) liposomes were utilized to encapsulate the magnolol in this study. The inhibitory efficiency of the liposome encapsulated magnolol on cell viability was higher than the pure magnolol. EPC liposome was found to have higher efficiency in inhibiting VSMCs than DPPC. The diameters of EPC and DPPC liposome which encapsulated magnolol became larger than pure EPC and DPPC liposomes. The photos from transmission electron microscopy (TEM) were demonstrated that the EPC and DPPC liposomes could be interfered by magnolol to form a homogeneous liposome. Addition of cholesterol to EPC and DPPC liposome could reduce th

ISSN:0009-4536    

DOI:10.1002/jccs.200800076

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractThis work presents a sol‐gel based biosensor for atrazine determination which has been obtained by introducing the enzyme polyphenol oxidase from apple tissue in a sol‐gel matrix. Apple tissue acts as a molecular recognition element. Atrazine is an inactive compound electrochemically; redox coupling of dopamine was used for studying atrazine behavior. Atrazine was determined by monitoring the inhibition power of polyphenol oxidase activity. The measurements were performed in 0.1 M KH2PO4‐NaOH buffer (pH 7.5). The effect of various experimental parameters such as pH, concentration of buffer, concentration of dopamine, incubation time and matrix composition has been investigated for optimum analytical performance. The biosensor consisted of 10.3% (w/w) of apple tissue. The bioelectrode exhibits a linear response for dopamine and atrazine concentrations in the range of 5.66 × 10−6−2.27 × 10−3M and 1 × 10−5−1 × 10−4M with a detection limit of 4.2 × 10−6and 5.5 × 10−6M, respectively. A correlation coefficient of 0.9945 and a relative standard deviation (R.S.D.) of 3.29% for dopamine, 0.9944 and 3.69%

ISSN:0009-4536    

DOI:10.1002/jccs.200800077

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractThe calculations for a water‐acetonitrile‐substituted phenols system and the comparison with the experimental parameters will be given. Here we study change in the nature of the interactions into the system with donor and acceptor electron substituents on the phenolic ring, the structures, relative energies and harmonic frequencies. The conformers showed a significant difference in the OH and CN band shift depending on the type of the hydrogen bond formed and the position of the substituent on the phenolic ring. The cyclical hydrogen bonds between water‐acetonitrile and substituted phenol OH are important evidence of the relative stability in the system under

ISSN:0009-4536    

DOI:10.1002/jccs.200800078

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractWe have computed and compared the geometries, the electronic properties and reactivity sites of a set of Alq3‐derivatives (5AP‐Mq3, M=Al, Ga, In) with potential use in organic light emitting diodes (OLED), using electronic and chemical reactivity descriptors. All the geometries were optimized with theab initioHartree‐Fock (HF) method and the 3‐21G basis set and the different descriptors were calculated at a B3LYP/3‐21G level of theory. The results show that the geometric structures were all distorted octahedral, where the geometrical parameters increase in the order 5AP‐Alq3<5AP‐Gaq3<5AP‐Inq3. The frontier molecular orbitals HOMO and LUMO are split in energy and strongly localized in a specific region of the ligands. The reactivity analysis shows that the atoms that receive electrons are those associated with the lowest unoccupied molecula

ISSN:0009-4536    

DOI:10.1002/jccs.200800079

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractIn this work, for the first time, copper ions(II) and cobalt ions(II) were successfully electrodepositioned into manganese oxide by cyclic voltammetry (CV), respectively. The results obtained from energy dispersive X‐ray analysis (EDX) testified that copper ions and cobalt ions were doped into manganese oxide, and the images, taken from scan electron spectroscopy (SEM) also proved that the morphology of the resultant MnO2was altered by the doped metal ions to some extent. Interestingly, specific capacitance, obtained by cyclic voltammograms (CVs), for the metal ions‐doped MnO2exhibited a higher value compared to the non‐doped MnO2. Developing a novel and simple method to generate the metal ions‐doped MnO2to improve the characteristics of MnO2is the main contribution of th

ISSN:0009-4536    

DOI:10.1002/jccs.200800080

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractA novel method for the indirect determination of sodium cefotaxime by the extraction‐flotation of cuprous thiocyanate is described in this paper. The experiment indicated that the degradation of sodium cefotaxime took place in the presence of 0.20 M sodium hydroxide in a boiling water bath for 40 min. At pH 4.0, the thiol group (‐SH) of the degradation product of sodium cefotaxime could reduce Cu(II) to Cu(I) for the formation of the emulsion CuSCN precipitation in the presence of ammonium thiocyanate. By determining the residual amount of Cu(II) in the solution and calculating the flotation yield of CuSCN, the indirect determination of sodium cefotaxime can be achieved. When the concentration of Cu(II) was 5.0 μg mL−1, a good linear relationship was obtained between the flotation yield of CuSCN and the amount of sodium cefotaxime in the range of 0.50∼20 μg mL−1. The linear equation is E = 1.329 + 2.654C with a correlation coefficient r = 0.9988. The detection limit of sodium cefotaxime of this proposed method evaluated by calibration curve (3σ/k) was found to be 0.39 μg mL−1. Every parameter has been optimized and the reaction mechanism has been studied. This method has been successfully applied to the determination of sodium cefotaxime in pharmaceutical formulations, human serum, and urine samples, respectively. Analytical results obtained with this novel method a

ISSN:0009-4536    

DOI:10.1002/jccs.200800081

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY