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151.
An access to different glycohybrids involving nucleophilic addition of N- and C-nucleophiles to the butenonyl glycosides followed by cyclization and subsequent reactions is reported. In the present communication, three different prototypes, β-D-glucopyranosylmethyl pyrazolines, β-D-glucopyranosylmethyl pyrimidines and β-D-glucopyranosylmethyl biphenyls, were prepared in moderate to good yields. 相似文献
152.
Nardjesse Nemiche Fatima Zohra Sebba Seghier Ould Kada 《Research on Chemical Intermediates》2014,40(8):3127-3134
The synthesis, characterization and self-assembly of a novel amphiphilic block copolymer containing a poly(N-vinylpyrrolidone) as a segment of hydrophilic and poly(4-vinyl benzene chloride) (PVBC) arms are reported. The copolymer was characterized by FT-IR spectroscopy 1H NMR. The composition and the molecular weights of the block copolymers were established using gel permeation chromatography and 1H NMR. The water-soluble fraction of poly(N-vinyl-2-pyrrolidone) (PVP)/PVBC block copolymers formed micelles which were investigated at 25 °C in water at 5 mg/ml concentration using a tensiometer. The morphology of micelles in aqueous solution was determined by the AFM, SANS, and SAXS methods. 相似文献
153.
The observed oscillatory linewidths of theV′=3 level ofB
3Π0+ state of I35Cl and I37Cl are explained as due to heterogeneous predissociation caused by the crossing of an unstableZ
1Π state. The crossing point and the slopes of the curves have been fixed to predict the observed linewidths. 相似文献
154.
155.
Thin-layer chromatography in combination with spectrophotometry has been applied for the separation and estimation of Hg(II) using silica gel layers impregnated with 2% oxalic acid as stationary phase with an ethyl acetate:acetone:formic acid:water (8:7:4:1) solvent system. Separation of Hg(II) from Hg(I) and of Th4+ from UO22+ is not affected by the presence of common anions in the sample solution. Hg(II) has been successfully separated from Ni(II), Cu(II), and Pb(II) over a wide range of pH (0.5–7.0) of sample solution. An attempt has been made to recover Hg(II) from rivers and industrial wastewaters. 相似文献
156.
Derivatives of thieno[2,3‐b]pyridine, 2‐thienylthiourea, 2‐thienylurea, 2‐thienylacetamide incorporating the 2‐phthalimidomethyl moiety have been synthesized. The synthesized compounds were then investigated for antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The compounds were also investigated for antifungal activity against Aspergillus niger and Fusarium oxysporium. The structures of the newly synthesized compounds have been established on the basis of their analytical and spectral data. 相似文献
157.
Dildar Ahmed Khaizran Fatima Ramsha Saeed Rashid Masih 《Natural product research》2016,30(17):2012-2016
Carissa opaca is a shrub known for its variety of medicinal applications. This study reports isolation and identification of four chemical compounds from its roots for the first time. The methanolic extract of the roots was fractionated into various solvents with increasing polarity. Chloroform fraction was subjected to column and thin layer chromatography to ultimately yield 2H-cyclopropanaphthalene-2-one, 7-hydroxy-6-methoxy-2H-1-benzopyran-2-one, 3-(4-methoxyphenyl)-2,6-dimethylbenzofuran and 5(1H)-azulenone, 2,4,6,7,8,8a-hexahydro-3,8-dimethyl-4-(1-methylethylidene)-,(8S-cis). They were identified by GC–MS analysis. The compounds exhibited considerable antimicrobial activities against Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger with zones of inhibition ranging from 10 to 13 mm as compared to the standard drug amoxicillin with zones of inhibition 13–17 mm under the similar conditions. In conclusion, the roots of C. opaca can provide new leads for future antimicrobial drugs. 相似文献
158.
S. Waheed N. Siddique M. Arif I. Fatima N. Khalid S. Rahman M. Daud M. Wasim 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(3):539-548
This paper presents the results of the proficiency test exercise conducted in Pakistan for the determination of trace elements
in mushroom reference material. Thirteen laboratories from different organizations of the country submitted trace elemental
data on Al, As, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hg, K, Li, Mg, Mn, Na, P, Pb, Rb Sc, Si, Sm, Sr, Th, Zn. Results for
Al, As, Br, Ca, Cd, Cl, Co, Cr, Cs, Cu, Fe, K, Mg, Mn, Na, Rb Sc, and Zn, in the mushroom material were reported by two or
more participating laboratories and could be subjected to statistical evaluation. The original data of these trace elements
was subjected to a computer program “Histo Version 2.1” provided by IAEA. The four outlier tests, i.e., Dixon, Grubbs, skewness
and kurtosis were applied to the data sets. Consensus (overall) mean values, absolute standard deviation, relative standard
deviation, standard error, median and range of values for these elements have been reported at a significance level of 0.05. 相似文献
159.
Galindo MA Houlton A Clegg W Harrington RW Dobado J Santoyo-Gonzalez F Linares F Romero MA Navarro JA 《Chemical communications (Cambridge, England)》2008,(32):3735-3737
The cyclic trinuclear system, [(en)(3)Pd(3)(4,7-phen)(3)](6+), undergoes a ligand exchange reaction with 5-R-2-hydroxypyrimidine derivatives (HRpymo; R = ethynylferrocene, 5-(dimethylamino)-N-(2-propynyl)-1-naphthalene sulfonamide) to give [(en)(3)Pd(3)(4,7-phen)(2)(Rpymo)](5+), functional supramolecular receptors of mononucleotides. 相似文献
160.
Gaffoor F Ford TA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(2):550-558
Ab initio calculations, at the level of second order M?ller-Plesset perturbation theory, and using a triple-zeta Gaussian basis set with polarization and diffuse functions on all atoms, have been carried out on the donor-acceptor complexes of boron trifluoride with ammonia and its mono-, di- and trimethyl derivatives. The structures, interaction energies and vibrational spectra of the complexes have been determined. An eclipsed and a staggered conformer have been examined for each complex, and the preferred conformer was found to be the staggered species in each case. The computed data have been compared with those for some similar complexes containing boron trifluoride and a series of oxygen and sulphur electron donors (water, hydrogen sulphide, methanol, methanethiol, dimethyl ether and dimethyl sulphide) and the effect of successive methyl substitution in all three series has been investigated. 相似文献