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991.
Jia Sun Peicheng Zhang Qi Wei Hang Xun Feng Tang Yongde Yue Li Li Xuefeng Guo Rong Zhang 《Tetrahedron letters》2014
Amarusine A (1), a new polyketide derivative possessing an unusual dioxaspiro[4.4]nonane derivative with a butyrolactone ring, was isolated from the leaves of Pleioblastus amarus. The structure and absolute stereochemistry of compound 1 were rigorously determined using UV, IR, HRESIMS, and 1D and 2D NMR techniques and by comparing experimental and calculated electronic circular dichroism (ECD) spectra. Amarusine A (1) exhibits a good antioxidant activity for scavenging the DPPH radical. A possible biosynthetic pathway was postulated. 相似文献
992.
Abstract. Two new coordination polymers {[Cd2(BDC)2(3‐bpmp)(H2O)2] · 2H2O}n ( 1 ) and [Cd2(BDC)2(4‐bpmp)]n ( 2 ) [H2BDC = 5‐hydroxy‐isophthalic acid, 3‐bpmp = 1,4‐bis(3‐pyridylmethy)piperazine, and 4‐bpmp = 1,4‐bis(4‐pyridylmethy) piperazine] were synthesized via hydrothermal synthesis, and further characterized by IR spectroscopy, elemental analysis, XRD, and X‐ray crystallography. Complex 1 shows a two‐dimensional (4,4) sql topology and complex 2 features an 8‐connected hex topology. Moreover, the luminescent properties of complexes 1 and 2 were investigated in the solid state at room temperature. 相似文献
993.
The TbIII compound [Tb(tci)(H2O)]n · n(DMF) ( 1 ) [H3tci = tri(2‐carboxythyl)isocyanurate, DMF = N,N′‐dimethylformamide] was synthesized by the reaction of terbium oxide, H3tci, and two drops of concentrated nitric acid in the presence of DMF and H2O. Single crystal X‐ray analysis reveals that it features a three‐dimensional (3D) framework based on infinite –Tb–COO–Tb– chains. The tci ligand in 1 links six different TbIII ions with its two carboxylate groups in μ2‐κ1O;κ2O,O′ mode and the third in μ2‐κ1O;κ1O′ mode. Thermal analysis reveals that it remains high thermal stability until 390 °C. Luminescence investigation shows that it emits characteristic green light of TbIII ions. 相似文献
994.
Yan‐Xue Chen Kang‐Kang Tang Xin Wang Bing‐Yi Chen Guo‐Qiang Qin Jin‐Hui Yang 《无机化学与普通化学杂志》2014,640(11):2292-2295
The zinc(II) coordination polymer [Zn3(BPT)2(μ2‐H2O)2(H2O)2]n · n(DMA) ( 1 ) (H3BPT = biphenyl‐3,4′,5‐tricarboxylic acid, DMA = N,N′‐dimethylactamide) was obtained by the solvothermal reaction of H3BPT with Zn(NO3)2 in DMA/H2O mixed solvent. Single crystal X‐ray analysis reveals that compound 1 has a complicated 3D framework containing linear trinuclear [Zn3(COO)4(μ2‐H2O)2] clusters as building subunits, which can be simplified into a (3,6)‐connected rtl topological network with the Schläfli symbol {4.62}2{42.610.83}. The calculated results of total and partial density of states (DOS) indicate that the luminescence of 1 mainly originates from intraligand charge transfer. 相似文献
995.
996.
Qing‐Hui Guo Zhan‐Da Fu Liang Zhao Mei‐Xiang Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(49):13766-13770
O6‐Corona[3]arene[3]tetraazines, a new class of macrocyclic compounds, were synthesized efficiently in a one‐pot reaction from the nucleophilic aromatic substitution reaction between 1,4‐dihydroxybenzene derivatives and 3,6‐dichlorotetrazine in warm acetonitrile. In the crystalline structure, the resulting macrocycles adopt highly symmetric structures of a regular hexagonal cavity with all bridging oxygen atoms and tetrazine rings located on the same plane with phenylene units orthogonally orientated. The constitutional aromatic rings are able to rotate around the macrocyclic annulus, depending on the steric effect of the substituents and temperature, in solution. The electron‐deficient nature revealed by cyclic voltammetry, differential pulse voltammetry, and characteristic absorbances at a visible region show the O6‐corona[3]arene[3]tetrazines to be suitable macrocyclic receptors for electron‐rich guests. 相似文献
997.
Chao Wang Changpeng Chen Jingyu Zhang Jian Han Qian Wang Kun Guo Pei Liu Mingyu Guan Yingming Yao Yingsheng Zhao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(37):10042-10046
An easily synthesized and accessible N,O‐bidentate auxiliary has been developed for selective C H activation under palladium catalysis. The novel auxiliary showed its first powerful application in C H functionalization of remote positions. Both C(sp2) H and C(sp3) H bonds at δ‐ and ε‐positions were effectively activated, thus giving tetrahydroquinolines, benzomorpholines, pyrrolidines, and indolines in moderate to excellent yields by palladium‐catalyzed intramolecular C H amination. 相似文献
998.
Determination of glutathione in single HepG2 cells by capillary electrophoresis with reduced graphene oxide modified microelectrode
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Determination of intracellular bioactive species will afford beneficial information related to cell metabolism, signal transduction, cell function, and disease treatment. In this study, the electrochemically reduced graphene oxide modified carbon fiber microdisk electrode (ER‐GOME) was used as a detector of CZE‐electrochemical detection and developed to detect glutathione (GSH). The electrocatalytic activity of the modified microelectrode was characterized by cyclic voltammetry. Under optimized experimental conditions, the concentration linear range of GSH was from 1 to 60 μM. When the S/N ratio was 3, the concentration detection limit was 1 μM. Compared with the unmodified carbon fiber microdisk electrode, the sensitivity was enhanced more than five times. With the use of this method, the average contents of GSH in single HepG2 cells were found to be 7.13 ± 1.11 fmol (n = 10). Compared with gold/mercury amalgam microelectrode, which was usually used in determining GSH, the electrochemically reduced graphene oxide modified carbon fiber microdisk electrode was friendly to environment for free mercury. Furthermore, there were several merits of the novel electrochemical detector coupled with CE, such as comparative repeatability, easy fabrication, and high sensitivity, hold great potential for the single‐cell assay. 相似文献
999.
Using n-PrPPh2 as the nucleophilic catalyst, the [4+2] cycloaddition reaction of the sulfamate-derived cyclic imines with allenoates works efficiently to yield various sulfamate-fused tetrahydropyridines in high yields with excellent diastereoselectivities. Using amino acid-based bifunctional phosphine as chiral catalyst, an asymmetric [4+2] cycloaddition reaction was achieved, giving chiral sulfamate-fused tetrahydropyridines in high yields with good enantiomeric excesses. 相似文献
1000.
Lewis acid-catalyzed tandem acylation–Nazarov cyclization for the syntheses of fused cyclopentenones
Ertong Li Changwei Li Jing Wang Jinqian Wang Lihong Dong Xiaohe Guo Chuanjun Song Junbiao Chang 《Tetrahedron》2014
Treatment of N-tosylpyrroles or N-tosylindoles with α-unsubstituted α,β-unsaturated carboxylic acids or unsaturated carboxylic acids having an α electron-withdrawing substituent in the presence of TFAA and a Lewis acid catalyst resulted in the formation of fused cyclopentenones via a tandem acylation–Nazarov cyclization sequence, while either the acylation product obtained or no reaction occurred in the absence of the Lewis acid catalyst. 相似文献