摘要:

AbstractA practical and efficient synthesis of 2‐substituted 7‐azaindoles has been developed using a cross‐coupling‐heteroannulation a

ISSN:0009-4536    

DOI:10.1002/jccs.200700081

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractAn efficient liquid‐phase synthesis of 2‐methyl‐2‐aryloxypropanoic acid derivatives with good yields and high purity on soluble polyethylene glycol (PEG) has been developed by treatment of PEG‐bound 2‐bromo‐2‐methylpropanoate with phenoxides in the presence of a catalytic amount of NBu4I and KI, and subsequent cleava

ISSN:0009-4536    

DOI:10.1002/jccs.200700082

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractAromatization of Hantzsch 1,4‐dihydropyridines was promoted by KHSO4, a relatively green chemical, supported onto bentonite to yield the corresponding pyridine derivatives in excellent yields. The reaction was carried out under mild and convenient condition

ISSN:0009-4536    

DOI:10.1002/jccs.200700083

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractA novel type of phosphated puerarin derivatives were synthesized through a simplified Atheron‐Todd reaction for the first time. The structure of these compounds were elucidated by IR, ESI‐MS and NMR. Moreover, the reason the dialkylphophite reagent had different chemselectivities toward different hydroxys on the puerarin was discus

ISSN:0009-4536    

DOI:10.1002/jccs.200700084

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractThe complexes of 2,11‐dithia‐4,5,6,7,8,9‐hexahydro[3.3]paracyclophane (dthhpcp) with Cu(I), i.e. [Cu2I2(dthhpcp)2]·2H2O1, or with Ag(I), i.e. [Ag(dthhpcp)(NO3)]thf2and [Ag(dthpcp)(CF3COO)]3, were prepared for structural study by single‐crystal X‐ray diffraction analysis. For these three complexes, dthhpcp serves as a bridging group in the polymeric structure through bridging sulfur atomsviametal, while the bonding of anion with the second metal atom forms the multi‐diminished structures. Complex1is a novel two‐dimensional coordination polymer composed of Cu6motifs, in which Cu2I2formed a square planar unit to link the dthhpcp molecule. The two oxygen atoms of the nitrate anion as a bridge for two Ag atoms in complex2provides a three‐dimensional channel framework of silver(I) with a tetrahydrofuran molecule as a guest inside the open cavities. In contrast, the analogous reaction with silver triflouroacetate gave a complex3, which is composed of infinite linear chains of‐Ag‐dthhpcp‐Ag‐dthhpcp‐ along theaaxis. Unit cell data: complex1, orthorhombic system, space groupP2(1)2(1)2(1), a= 19.2982(11) Åb= 16.5661(10) Å,c= 25.3006(15) Å, β = 90°,Z= 8; complex2, orthorhombic system, space groupPna2(1), a= 8.8595(6) Å,b= 12.6901(9) Å,c= 19.8449(14) Å, β = 90°,Z= 4; complex3, monoclinic system, space groupP2(1)/n, a= 8.845(3) Å,b= 20.841(6)

ISSN:0009-4536    

DOI:10.1002/jccs.200700085

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractBrilliant blue R adsorption from aqueous solution on activated carbon produced from corncob waste was investigated. The carbon samples were characterized by XRD, SEM, EDS and FTIR methods. The surface functional groups (carboxyl, lactone or phenol, ether, hydroxyl) disappeared at high activation temperature, resulting in a high amount of carbon with respect to oxygen. The kinetic studies of the adsorption of brilliant blue R on carbon at 10 and 45 °C showed that the first order and intraparticle diffusion models apply to the data. The reaction rate increased with the increase in temperature of adsorption/activation. Thermodynamic parameters like ΔE#, ΔH#and ΔS#for adsorption were calculated from the kinetic data. The positive value of ΔH#shows the endothermic nature of adsorption which decreased with the increase in adsorption/activation temperature. The negative values of ΔS#reflect a decrease in the disorder of the system at the solid‐solution interface during adsorption. Equilibrium studies showed that the data fits the Langmui

ISSN:0009-4536    

DOI:10.1002/jccs.200700086

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractThree novel supramolecular arrays of zigzag polyaromatic salts are reported. Both the conformation and disposition of the dications are subjected to various noncovalent interactions. Thus, the presence or absence of the π‐π interacting enclathrated molecules, the efficient packing and the involved hydrogen bonding interactions of anions, as well as the increased hydrophobic property of the dications themselves exert influe

ISSN:0009-4536    

DOI:10.1002/jccs.200700087

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractA highly sensitive spectrofluorimetric method was developed for the determination of fenoterol HBr in pharmaceutical preparations. The method is based on the nitrosation of fenoterol followed by reaction with 2‐cyanoacetamide in the presence of ammonia and measuring the produced fluorescence at 380 nm after excitation at 338 nm. All the variables affecting the reaction conditions were carefully studied and optimized. Linear calibration graph was obtained in the range of 0.064–0.64 μg.mL−1with a correlation coefficient of 0.9999 and a relative standard deviation of 0.83%. The method was applied to dosage forms and the results obtained agreed well with those obtained by the official method. A proposal of the reaction pathway was sug

ISSN:0009-4536    

DOI:10.1002/jccs.200700088

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractIn this work, the absorption spectral characteristics and color‐change reaction mechanism of cobalt(II) chloride(CoCl2) in alcohol organic solvents has been investigated in the presence of water, and then the optimum conditions for determining the water content in the solvents were selected. Results indicated that the absorption spectra of CoCl2in alcohols decreased with the increment of water content. At the maximum absorption wavelength of 656 nm, there were good linear relationships between the logarithm of the absorbance and the water content in organic solvents such as ethanol, n‐propanol, iso‐propanol and n‐butanol with related coefficients in the range of 0.9996˜0.9998. For determining water content in organic solvents, this method is simple, rapid, sensitive, reproducible and environmentally friendly. Furthermore, the linear range cannot restrict determination of the water content in organic solvents. This method had been applied to determine the water content in ethanol and n‐butanol with satisfactory recovery of water in n‐butanol between 98

ISSN:0009-4536    

DOI:10.1002/jccs.200700089

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY

摘要:

AbstractA method for speciation of Cr(III) and Cr(VI) in real samples has been developed. Cr(VI) has been separated from Cr(III) and preconcentrated as its pyrrolidinedithiocarbamate (APDC) complex by using a column containing Amberlite XAD–2000 resin and determined by FAAS. Total chromium has also been determined by FAAS after conversion of Cr(III) to Cr(VI) by oxidation with KMnO4. Cr(III) has been calculated by subtracting Cr(VI) from the total. The effect of pH, flow‐rate, adsorption and batch capacity and effect of various metal cations and salt anions on the sorption onto the resin were investigated. The adsorption is quantitative in the pH range of 1.5–2.5, and Cr(VI) ion was desorbed by using H2SO4in acetone. The recovery of Cr(VI) was 97 ± 4 at a 95% confidence level. The highest preconcentration factor was 80 for a 200 mL sample volume. The adsorption and batch capacity of sorbent were 7.4 and 8.0 mg g−1Cr(VI), respectively, and loading half time was 5.0 min. The detection limit of Cr(VI) is 0.6 μg/L. The procedure has been applied to the determination and speciation of chromium in stream water, tap water, mineral spring water and spring water. Also, the proposed method was applied to total chromium preconcentration in microwave digested moss and rock samples with satisfactory results. The developed method was validated with CRM‐TMDW‐500 (Certified Reference Material Trace Metals in Drinking Water) and BCR‐CRM 144R s (Certified Reference Material Sewage Sludge, Domestic Origin) and the results obtained were in good agreement with the certified values. The relative standard deviation

ISSN:0009-4536    

DOI:10.1002/jccs.200700090

出版商:WILEY‐VCH Verlag    

年代:2007

数据来源: WILEY