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101.
A new pentacyclic triterpene, named ursethoxy acid (1) was isolated from the aerial parts of Lantana camara Linn. Its structure has been elucidated as 3,25-epoxy-3alpha-ethoxy-urs-12-en-28-oic acid through extensive 1D- and 2D-NMR (COSY-45, NOESY, J-resolved, HMQC and HMBC) studies. 相似文献
102.
Bacchi A Costa M Gabriele B Pelizzi G Salerno G 《The Journal of organic chemistry》2002,67(13):4450-4457
A variety of prop-2-ynylamides have been carbonylated under oxidative conditions to give oxazolines, oxazolines with chelating groups, and bisoxazolines bearing an (alkoxycarbonyl)methylene chain at the 5 position in good yields. The cyclization-alkoxycarbonylation process was carried out in alcoholic media at 50-70 degrees C and under 24 bar pressure of 3:1 carbon monoxide/air in the presence of catalytic amounts of 10% Pd/C or PdI2 in conjunction with KI. Cyclization occurred by anti attack of an oxygen function on the palladium-coordinated triple bond, followed by stereospecific alkoxycarbonylation, strictly resulting in E-stereochemistry. The structures of representative oxazolines and bisoxazolines have been determined by X-ray diffraction analysis. 相似文献
103.
Sabira Begum SyedaQamar Zehra Aneela Wahab BinaShaheen Siddiqui 《Helvetica chimica acta》2006,89(9):1932-1941
Three new pentacyclic triterpenoids, camarin ( 1 ), lantacin ( 2 ), and camarinin ( 3 ) were isolated from the aerial parts of Lantana camara Linn ., together with seven known compounds. The structures of the new constituents were elucidated by chemical transformation, HR‐EI mass spectrometry, and NMR spectroscopy, including 1D (1H‐ and 13C‐NMR) and 2D (1H,1H‐COSY, NOESY, 1H,1H‐TOCSY, J‐resolved, HMQC, and HMBC) experiments. 相似文献
104.
Stefano Rossi Mirco Bizzotto Flavio Deflorian Michele Fedel 《Surface and interface analysis : SIA》2019,51(12):1194-1206
Aluminium foam is obtained by the production of air into metallic melt. This material shows a very low density together with good mechanical properties, high impact energy absorption, and fire resistance. Different production ways to obtain metallic foam are possible. Considering the cost, the Alporas process is particularly interesting. By means of this production method, a block of metallic foam with close cells is obtained. By slicing, foam panels are obtained. The mechanical cut promotes the formation of an open cells texture on the surface. In this last case, the complex morphology of aluminium foam could be a critical point considering the corrosion behavior in aggressive environments, where localized corrosion phenomena, as pitting or crevice corrosion, are likely to occur. The anodizing treatment is one of the most used methods to improve the corrosion resistance of aluminium and aluminium alloys. The aim of this paper is to perform an anodization treatment to enhance the corrosion resistance of aluminium foam. Constant voltage anodization (12 V for 60 min) and pulsed current anodization (0.04 A/cm2 for 60 seconds and 0.01 A/cm2 for 15 seconds, repeated for 15 cycles) have been carried out in 15 wt% H2SO4 at 20°C. The anodized samples are observed in cross section by optical and electronic microscopes to investigate the structure of the anodic oxide layer and the presence of defects and to measure the thickness of the layer. The corrosion protection performance and the compactness of layers are evaluated using acetic salt spray test and electrochemical impedance spectroscopy. 相似文献
105.
Ba-Abbad Muneer M. Takriff Mohd S. Benamor Abdelbaki Mohammad Abdul Wahab 《Journal of Sol-Gel Science and Technology》2017,81(3):880-893
Journal of Sol-Gel Science and Technology - Haematite (α-Fe2O3) nanoparticles (NPs) of different sizes and morphologies were prepared from two different iron precursors (iron acetate (A) and... 相似文献
106.
Lantanilic acid, camaric acid and oleanolic acid possessing nematicidal activity were isolated from the methanolic extract of the aerial parts of Lantana camara Linn. through bio-assay guided fractionation. These compounds exhibited 98%, 95% and 70% mortality respectively against root-knot nematode Meloidogyne incognita at 0.5% concentration. Conventional nematicide furadan showed 100% mortality at this concentration. 相似文献
107.
M. Z. Barakat M. F. Abdel Wahab Y. M. Megahed 《Monatshefte für Chemie / Chemical Monthly》1964,95(6):1613-1622
Zusammenfassung Der Ascorbinsäuregehalt von fünf Leguminosen, nämlich Vicia faba, Vigna sinensis, Phaseolus vulgaris, Trigonella foenum graecum und Lupinus termis, wird angegeben. Die durchschnittliche Veränderung im Vitamin C-Gehalt der Samen während der Keimung wird aufgezeigt. Die Auswirkung von -Strahlen, die kleine Mengen von radioaktivem H3
32PO4 aussenden, sowie die der -Strahlung von radioaktivem131J,137Cs oder60Co auf die Keimlinge wird beschrieben.
Mit 9 Abbildungen 相似文献
The ascorbic acid content of five sorts of leguminous plants, viz., Vicia Faba, Vigna Sinensis, Phaseolus Vulgaris, Trigonella Foenum Graecum and Lupinus Termis is given. The average variations in the vitamin C content of the seeds during germination are shown. The effects or -irradiation emitted from small doses of radioactive H3 32PO4 as well as -irradiation of131I,137Cs or60Co on the seedlings are demonstrated.
Mit 9 Abbildungen 相似文献
108.
109.
Rizk E. Khidre Bakr F. Abdel‐Wahab Abdelbasset A. Farahat Hanan A. Mohamed 《Journal of heterocyclic chemistry》2016,53(1):13-31
The data on the synthetic methods of the pyrazole‐3(5)‐carboxylates published over the last years are reviewed here for the first time. 相似文献
110.