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Synthesis of benzopyrano[2,3-c]pyrazoles and 3-triazolonyliminocoumarins was successfully performed using heterocyclization of 3-cyano iminocoumarin or their N-ethoxycarbonylated derivatives with semicarbazide reagents. Elemental analysis, infrared, and 1H NMR spectral data confirmed the molecular structure of the newly synthesized compounds. 相似文献
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2-Amino-4-(2-hydroxynaphthyl)-4H-chromene-3-carbonitriles were synthesized by Michael addition of various 3-cyanoiminocoumarins and β-naphthol in good yield. The heterocyclization of these materials in an acidic medium leads new heterocyclic compounds, which have not previously been described, in moderate to good yields and good selectivity. The synthesized compounds were characterized by infrared, 1H NMR, 13C NMR, two-dimensional NMR, and elemental analysis. 相似文献
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The low-temperature single-crystal polarized absorption and the luminescence spectra of Cs2[CrCl2(H2O)4]Cl3 are theoretically analyzed in order to determine the electronic structure of the trans-[CrCl2(H2O)4]+ complex. This study, based on the Racah theory, leads to a good agreement between the theoretical and experimental energy levels. The electronic-exited state 4T2g(Oh) is split into 4Eg and 4B2g components due to the lowering of the symmetry from Oh to D4h. The polarized absorption spectrum and the theoretical energies show that the 4Eg(D4h) state is lower in energy than the 4B2g(D4h) state. The resolved vibronic structure in the luminescence spectrum reveals a progression in a non-totally symmetric b1g mode, a manifestation of a Jahn-Teller effect in the emitting state 4T2g(Oh). Both Jahn-Teller and spin-orbit coupling in the orbitally degenerated 4Eg(D4h) state are necessary to account for the spectroscopic observations. 相似文献
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Maher Kammoun Imed Koubaa Yassine Ben Ali Raoudha Jarraya Youssef Gargouri Mohamed Damak Sofiane Bezzine 《Applied biochemistry and biotechnology》2010,162(3):662-670
The aim of the present work was to evaluate the anti-inflammatory properties of Cynara cardunculus L. (Asteraceae) during its growth using various solvents such as n-hexane, dichloromethane, acetone, and methanol for air-dried leaves and stems. The anti-inflammatory activities of crude
extracts were evaluated by measuring the inhibition potency of mammalian non-pancreatic phospholipases A2 (hG-IIA). The methanol
and acetone extracts of leaves harvested in February exhibit potent inhibition of hG-IIA (IC50 = 50 and 70 μg/ml, respectively). However, the acetone extract of stems harvested in December inhibits the hG-IIA with a
lower IC50 around 130 μg/ml. Fractionation on silica gel and hydrophobic gel of the methanol extract of leaves harvested in February
increases the inhibitory effect, and the IC50 reached 10 μg/ml. 相似文献
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A theoretical energy-level analysis was based on parametric Hamiltonian for the 4f11 electronic configuration of Er3+ ions in C3v center, and it permitted a phenomenological characterization of crystal-field (CF) Hamiltonian parameters. This characterization allowed us to calculate the energy of the missing stark levels of the 4I15/2 and 4I13/2 states and to confirm the presence of a single emission center with C3v symmetry. The calculated CF and strength parameters are compared with those obtained for Sm3+, Pr3+ and Yb3+ ions in the same host and with Er3+ in other isostructural hosts. 相似文献
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