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1.
SOLIMAN A.Y. BAKEER H.M. ATTIA LA.Science Department Faculty of Teachers P.O.Box Alhasa Saudi Arabia Chemistry Department Faculty of Science Fayoum Cairo University EgyptFaculty of Engineering Ain Shames University Egypt 《中国化学》1996,14(6):532-540
3-(4-Phenyl) benzoyl propionic acid was used as the starting material for the synthesisof furanones (2), pyrrolinones (5), pyridazinones (7), benzoxazinones (8) and quinazolinones (9-11). The behaviour of the derivatives of furanones and benzoxazinones toward different nucleophiles is reported. 相似文献
2.
Karoll Ferrer Katy Díaz Miroslav Kvasnica Andrs F. Olea Mauricio Cuellar Luis Espinoza 《Molecules (Basel, Switzerland)》2021,26(4)
The metabolism of brassinosteroid leads to structural modifications in the ring skeleton or the side alkyl chain. The esterification and glycosylation at C-3 are the most common metabolic pathways, and it has been suggested that conjugate brassinosteroids are less active or inactive. In this way, plants regulate the content of active brassinosteroids. In this work, the synthesis of brassinosteroid 24-norcholane type analogs conjugated at C-3 with benzoate groups, carrying electron donor and electron attractant substituents on the aromatic ring, is described. Additionally, their growth-promoting activities were evaluated using the Rice Lamina Inclination Test (RLIT) and compared with that exhibited by brassinolide (used as positive control) and non-conjugated analogs. The results indicate that at the lowest tested concentrations (10−8–10−7 M), all analogs conjugated at C-3 exhibit similar or higher activities than brassinolide, and the diasteroisomers with S configuration at C-22 are the more active ones. Increasing concentration (10−6 M) reduces the biological activities of analogs as compared to brassinolide. 相似文献
3.
A Vilsmeier salt supported on solid phase was prepared using piperazine bound to Merrifield resin. Piperazine was selected because it contains two secondary amines: one of the amines is protected upon binding to the resin, and the second was formylated to give resin-1-N-piperazine-4-N-carboxaldehyde (9). Activation of the formamide with either bis(trichloromethyl)carbonate (BTC) or POCl(3) afforded the Vilsmeier salt 10. Several olefins were used to test the supported Vilsmeier reagent. The in-solution activation with BTC and POCl(3) of various secondary amides was also evaluated: dimethylformamide (1), N-methyformanilide (4), 4-formylmorpholine (5), and 1,4-dicarboxylpiperazine (6), which showed that amides with one additional heteroatom increase the yields in the Vilsmeier salt formation. 相似文献
4.
Four new and seven known diterpenes have been isolated from the dichloromethane extract of the aerial parts of Calceolaria polifolia. The structures of the new compounds were established by spectroscopic evidence. 相似文献
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6.
Roa Luis Espinoza Andrea Muñoz Ariana Ladrón de Guevara María L. 《Frontiers of Physics》2019,14(6):1-30
Frontiers of Physics - Recently, the BESIII collaboration has reported numerous measurements of various D(s) meson semileptonic decays with significantly improved precision. Together with similar... 相似文献
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8.
Daniel G. Espinoza 《Operations Research Letters》2010,38(2):115-120
Recent advances on the understanding of valid inequalities from the infinite group relaxation has opened the possibility of finding a computationally effective extension to GMI cuts. In this paper, we investigate the computational impact of using a subclass of minimally valid inequalities from this relaxation on a wide set of instances. 相似文献
9.
L. Carolina Espinoza Mario Aranda David Contreras Adolfo Henríquez Dr. Ricardo Salazar 《ChemElectroChem》2019,6(18):4801-4810
The sp3/sp2 ratio present in boron-doped diamond (BDD) electrodes conditions the way in which organic compounds are oxidized and transformed to CO2 during anodic oxidation. A higher content of sp3 carbon on the surface favors the generation of hydroxyl radicals over the oxygen evolution reaction, which generates different degradation byproducts. In this work, we studied the degradation of aniline by anodic oxidation using five BDD electrodes with different sp3/sp2 ratios in sulfate and chloride media. Aniline was degraded using the five BDD electrodes in both electrolytes, and clear differences were observed in the intermediates produced during the electrolysis. BDD electrodes with higher sp3 proportions allowed for greater degradation and mineralization of aniline with lower molecular weight and the production of fewer toxic organic byproducts. Degradation pathways for aniline in sulfate and chloride media are proposed, evidencing the differences in the oxidation mechanisms for aniline and its byproducts due to the varying sp3/sp2 ratio in the BDD electrodes. 相似文献
10.
A compact graph-like space is a triple ⧹