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691.
The regio- and stereospecific synthesis of dl-4,5-dibromo-4,5-dideoxy-3,6-O-methyl-chiro-inositol is reported. Bromination of p-benzoquinone followed by reduction of the carbonyl groups with NaBH4 gave the corresponding trans-dibromodiol compound, which was reacted with sodium methoxide to produce dimethoxy conduritol-B. Regiospecific bromination of the alkene moiety furnished the desired chiro-inositol derivative. 相似文献
692.
693.
Zeliha Hayvali Hakan Dal Pinar Köksal Duygu Şahin Tuncer Hökelek 《Structural chemistry》2010,21(4):837-845
A series of benzyloxybenzaldehyde derivatives (1–3) were prepared by the reactions of 4-nitrobenzyl bromide with 4-hydroxy-3-methoxybenzaldehyde (vanillin), 2-hydroxy-3-methoxybenzaldehyde
(o-vanillin) and 2-hydroxy-4-methoxybenzaldehyde. When the reaction time is quite long, benzofuran derivatives (4 and 5) were obtained by the reactions of ortho-hydroxyaldehydes with the 4-nitrobenzyl bromide. Condensation reactions among the three benzyloxybenzaldehyde derivatives
(1–3) with 2-aminomethylfuran (furfurylamine) yielded the new imine compounds (6–8). The structures of these aldehydes (1–3), benzofuran derivatives (4 and 5) and imine compounds (6–8) were confirmed on the basis of elemental analyses, IR, 1H NMR and 13C NMR and mass spectroscopy. The solid-state structures of compounds 4–6 were determined by single-crystal X-ray crystallography. 相似文献
694.
The structural features of the methylated pyridine series have been studied by quantum chemical methods. The aromatic character
of these molecules is derived from the frontier molecular orbital energies, harmonic oscillator model of aromaticity (HOMA),
and nucleus independent chemical shift (NICS) values. Hybrid density functional theory with 6-311++G(d,p) basis set was employed
for all calculations. 相似文献
695.
Ayşe Aytaç Veli Deniz Murat Şen El-Sayed Hegazy Olgun Güven 《Radiation Physics and Chemistry》2010,79(3):297-300
The effects of gamma and e-beam irradiation on mechanical and structural properties of nylon 66 (Ny 66), nylon 6 (Ny 6) and poly(ethylene terephthalate) (PET) fabrics used in tyres were investigated. The untreated (greige), treated cords and calendered fabrics were irradiated at different doses. It is found that the effects of high energy irradiation on greige, treated cords and calendered fabrics are similar. No protective effect of compounds used in calendering was observed against radiation-induced oxidative degradation. The deterioration effect of gamma irradiation on mechanical properties is much higher than that of e-beam irradiation for all types of samples. Limiting viscosity numbers of both gamma and e-beam irradiated nylon 6 and nylon 66 cords were found to decrease with increasing dose. It is concluded that PET calendered fabric has higher resistance to ionizing radiation. Ny 6 and Ny 66 calendered fabrics are more sensitive even at low doses. Therefore, the effects of high energy irradiation on tyre cords have to be taken into consideration during tyre design reinforced with particularly Ny fabrics if pre-vulcanization with high energy radiation is to be applied. 相似文献
696.
A new, simple, and fully validated gas chromatography–mass spectrometry (GC–MS) method was presented for quantitative analysis of milnacipran (MNP) in human plasma. MNP was efficiently derivatized with N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) before analysis. The role of catalyst, temperature, time, solvent on the trimethylsilylation reaction were evaluated. The proposed method was fully validated by assessment of the following parameters: limits of detection and quantitation, precision, accuracy, linearity, specificity, stability, extraction recovery and robustness/ruggedness. The limit of quantitation (LOQ) was 30 ng mL?1. The calibration curve was linear (r 2 > 0.9988) in the range 30–500 ng mL?1. The method was found specific, precise, accurate, selective and reliable according to validation data. This developed method was successfully applied to determine the steady state concentration of MNP in patients. 相似文献
697.
In order to envision the radiation exposure during Neutron Activation Analysis (NAA) experiments, a software called Activity
Predictor is developed using JavaTM programming language. The Activity Predictor calculates activities, exposure rates and gamma spectra of activated samples
for NAA experiments performed at Radiation Science and Engineering Center (RSEC), Penn State Breazeale Reactor (PSBR). The
calculation procedure for predictions involves both analytical and Monte Carlo methods. The Activity Predictor software is
validated with a series of activation experiments. It has been found that Activity Predictor software calculates the activities
and exposure rates precisely. The software also predicts gamma spectrum for each measurement. The predicted spectra agreed
partially with measured spectra. The error in net photo peak areas varied from 4.8 to 51.29%, which is considered to be due
to simplistic modeling, statistical fluctuations and unknown contaminants in the samples. 相似文献
698.
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700.
Hasan Tanak Karataş Şadiye Meral Seher Ağar Ayşen Alaman 《Crystallography Reports》2020,65(7):1221-1225
Crystallography Reports - A novel Schiff base compound was synthesized and characterized by IR spectroscopy and X-ray diffraction method. The compound crystallizes in monoclinic space group P21/c... 相似文献