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Composition of volatile organic compounds (VOCs) in flowers of Astragalus lagopoides was studied using a hydrodistillation extraction procedure coupled with gas chromatography-mass spectrometry. The analyses allowed the identification of a number of 25 compounds, among which the presence of several bioactive aromatic derivatives such as guaiacol, eugenol, linalool, α- and 4-terpineol as well as nerol was attention-grabbing. Moreover, some other compounds like cyclohexane, 2-bromoethyl with repellent function also appeared to be present in the flower. As a result, the floral VOCs profile of A. lagopoides might reflect an adaptation to attract specialised pollinator insects. These findings provide important information for advances in understanding the ecological and evolutionary perspectives of pollination biology of the giant genus Astragalus. 相似文献
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Ferric perchlorate catalyzes the three-component condensation reaction of o-phenylenediamine, aromatic aldehydes, and cyclohexyl isocyanide to afford the corresponding N-cyclohexyl-3-aryl-quinoxaline-2-amines in good yields. 相似文献
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The adduct produced in the reaction between alkyl isocyanides and dialkyl acetylenedicarboxylates was trapped by 2,2,5-trimethyl-1,3-dioxane-4,6-dione (methyl Meldrum's acid), to afford highly functionalized ketenimines in good yields. 相似文献
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Bita Shafaatian Atefeh Baharian 《Phosphorus, sulfur, and silicon and the related elements》2017,192(10):1102-1109
New Schiff base complexes of zinc(II), copper(II), nickel(II), and vanadium(IV) were synthesized using the Schiff base ligand formed by the condensation of 2-aminoethanethiol and 2-hydroxy-1-naphthaldehyde. The tetradentate Schiff base ligand N,N´-(3,4-dithiahexane-1,6-diyl)bis(2-hydroxy-1-naphthaleneimine), containing a disulfide bond, was coordinated to the metal(II) ions through the two azomethine nitrogen atoms and two deprotonated phenolic oxygens of two different ligands which was connected to each other by sulfur-sulfur bond. The molar conductivity values of complexes in DMSO solvent implied the presence of nonelectrolyte species. The fluorescence properties of the Schiff base ligand and its complexes were studied in dimethylsulfoxide. The Schiff base ligand and its complexes were characterized by FT-IR, 1H NMR, UV/Vis spectroscopies, elemental analysis, and conductometry. The crystal structure of tetradentate Schiff base ligand was characterized by single crystal X-ray diffraction. The Schiff base ligand was contained disulfide bond. Furthermore, the binding interaction of these complexes with calf thymus DNA (CT-DNA) was investigated by different methods. 相似文献
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Evaporite Borate‐Containing Mineral Ensembles Make Phosphate Available and Regiospecifically Phosphorylate Ribonucleosides: Borate as a Multifaceted Problem Solver in Prebiotic Chemistry 下载免费PDF全文
Dr. Hyo‐Joong Kim Prof. Yoshihiro Furukawa Prof. Takeshi Kakegawa Dr. Andrei Bita Prof. Romulus Scorei Prof. Steven A. Benner 《Angewandte Chemie (International ed. in English)》2016,55(51):15816-15820
RNA is currently thought to have been the first biopolymer to support Darwinian natural selection on Earth. However, the phosphate esters in RNA and its precursors, and the many sites at which phosphorylation might occur in ribonucleosides under conditions that make it possible, challenge prebiotic chemists. Moreover, free inorganic phosphate may have been scarce on early Earth owing to its sequestration by calcium in the unreactive mineral hydroxyapatite. Herein, it is shown that these problems can be mitigated by a particular geological environment that contains borate, magnesium, sulfate, calcium, and phosphate in evaporite deposits. Actual geological environments, reproduced here, show that Mg2+ and borate sequester phosphate from calcium to form the mineral lüneburgite. Ribonucleosides stabilized by borate mobilize borate and phosphate from lüneburgite, and are then regiospecifically phosphorylated by the mineral. Thus, in addition to guiding carbohydrate pre‐metabolism, borate minerals in evaporite geoorganic contexts offer a solution to the phosphate problem in the “RNA first” model for the origins of life. 相似文献
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Cracks are one of the common defects in structural components that may ultimately lead to failure of structures if not detected. Generally, most of the vibration based crack detection methods transform measured vibration responses from time-domain into frequency-domain using Fourier or wavelet transform for damage detection. However, it would be more convenient if the vibration responses could be analysed in their original time-domain. Therefore, a practical method based on probability distribution function is proposed which performs all the data processing in time-domain for the purpose of crack detection in beam-like structures. The application of the proposed method to both numerical and experimental examples and their results are presented. 相似文献
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α‐Amino nitriles are synthesized by the three‐component coupling reaction of aldehydes, amines and trimethylsilyl cyanide using FeCl3 as a solid acid catalyst, under solvent‐free conditions in good yields. The catalyst was recovered by simple filtration and was recycled in subsequent reactions. 相似文献