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991.
H. Surya Prakash Rao S. Senthilkumar K. Gopu Shaik Rafi 《Chemistry of Heterocyclic Compounds》2007,43(3):292-297
The microwave-mediated reaction of 4-aryl-4-oxobutanoic acids with benzylamines furnished 1-arylmethyl-3-[(E)-1-arylmethylidene]-5-phenyl-2,3-dihydro-1H-pyrrolones.
This result is in contract to the earlier report on this reaction conducted under neat conditions. Structures for the products
were assigned on the basis of spectral data and confirmed by independent synthesis.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 368–373, March, 2007. 相似文献
992.
Norman H. Tennent Sophia R. Su Craig A. Poffenberger Andrew Wojcicki 《Journal of organometallic chemistry》1975,102(4):C46-C48
The reaction of Na[η5-C5H5Fe(CO)2] with large excess of SO2 in THF at ?78°C followed by warming to room temperature affords an iron—dithionite complex, (η5-C5H5)(CO)2FeS(O)2S(O)2Fe(CO)2(η5-C5H5). 相似文献
993.
The electrochemistry of dopamine (3-hydroxytyramine) was studied by cyclic voltammetry at a glassy carbon electrode in the presence of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) micelles at different pH. The anodic peak potential (E(pa)) and peak current (I(pa)) were found to be remarkably dependent on the charge and the concentration of the surfactant. The E(pa) and I(pa) change abruptly around the critical micellar concentration (CMC) of the surfactants and reach a plateau above the CMC. The E(pa) at the plateau shifts to more positive values in the cationic CTAB micellar solution, e.g. from 180 mV vs SCE in aqueous solution at pH 6.8 to 410 mV in CTAB micelle, whilst it shifts to less positive values in the anionic SDS micellar solution, e.g. 150 mV at pH 6.8. Therefore, the overlapped anodic peaks of dopamine and ascorbic acid in the mixture of the two compounds in aqueous solutions can be separated in CTAB micelles since the micelle shifts the E(pa) of ascorbic acid to less positive values. The two peaks are separated by ca. 400 mV at pH 6.8 in CTAB micelle, hence dopamine can be determined in the presence of 100 times excess of ascorbic acid. In SDS micelle and in the presence of ascorbic acid, the I(pa) of dopamine is greatly enhanced due to the catalytic oxidation of the latter that enables quantitative determination of both compounds. 相似文献
994.
Changlun Shao Zhiyong Guo Hong Peng Guangtian Peng Zhongjing Huang Zhigang She Yongcheng Lin Shining Zhou 《Chemistry of Natural Compounds》2007,43(4):377-380
A new isoprenyl phenyl ether, 3-hydroxy-4-(3-methylbut-2-enyloxy)benzoic acid methyl ester (1), together with 4-hydroxybenzoic acid (2), 2-hydroxy-6-methylbenzoic acid (3), and 4-hydroxy-3-methoxybenzoic acid (4) were isolated from Mangrove fungus (No. B60) from the South China Sea. The structures of the compounds were established
on the basis of NMR spectroscopic and mass spectrometric data. In the preliminary bioassay, compound 1 exhibited antibacterial and antifungal activities. Compound 1 also inhibited cytotoxicity to the hepG2 cell line with an IC50 value of 10.0 μg/mL.
Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 313–314, July–August, 2007. 相似文献
995.
Tomislav Došlić 《Journal of mathematical chemistry》2007,41(3):217-229
A global forcing set in a simple connected graph G with a perfect matching is any subset S of E(G) such that the restriction of the characteristic function of perfect matchings of G on S is an injection. The number of edges in a global forcing set of the smallest cardinality is called the global forcing number
of G. In this paper we prove several results concerning global forcing sets and numbers of benzenoid graphs. In particular, we
prove that all catacondensed benzenoids and catafused coronoids with n hexagons have the global forcing number equal to n, and that for pericondensed benzenoids the global forcing number is always strictly smaller than the number of hexagons. 相似文献
996.
Antonilêni F. D. Medeiros Ana Flávia O. Santos F. S. de Souza I. D. B. Júnior J. Valdilânio J. V. V. Procópio D. P. de Santana R. O. Macêdo 《Journal of Thermal Analysis and Calorimetry》2007,89(3):775-781
Compatibility studies between active drugs and excipients are substantial in the pharmaceutical technology. The objective
of the present work was to develop pre-formulated mixtures of metronidazole (MT) obtained by spray drying (SPDR) and their
thermoanalytical characterization. Dynamic and isothermal TG, conventional DSC and DSC coupled to a photovisual system were
used. DSC experiments with both techniques confirmed the homogeneity of the conventional and pre-formulated mixtures. The
TG data made possible the comparison the thermal stability of the different mixtures. Similar thermal stabilities were found
of the conventional and pre-formulated mixtures, with slower particles sizes of MT. 相似文献
997.
Ai Jun HOU Hui YANG Bei JIANG Qin Shi ZHAO Yan Ze LIU Zhong Wen LIN Han Dong SUN Laboratory of Phytochemistry Kunming Institute of Botany Chinese Academy of Sciences Kunming Department of Phytochemistry Henan College of Traditional Chinese 《中国化学快报》2000,11(9)
In continuation of our research on diterpenoids in the Isodon species, several newcompounds"' were obtained from the leaves oflsodon xerophilus (C. Y. Wu et H. W. Li)H. Hara (Labiatae), a perennial shrub native to Yunnan province. Further fractionation ofthe EtOAc extract led to the isolation of tWo new enl-kauranoids, xerophilusin E (l) andxerophilusin F (2). This paper deals with the structUral elucidation of the newcompounds.Xerophilusin E (l), a minor constitUent, was obtained as p… 相似文献
998.
Sham M. Sondhi Shefali Rajvanshi Nirupma Singh Shubhi Jain Anand M. Lahoti 《Central European Journal of Chemistry》2004,2(1):141-187
Non steroidal anti-inflammatory drugs are the most widely used medicines for relief of pain. These drugs have some side effects,
particularly toxicity in the gastrointestinal tract and kidneys. Various approaches have been used for obtaining safer anti-inflammatory
drugs. In this review we have summarized the recent developments in the following areas; (i) mode of action of NSAIDs (ii)
Role of COX-1 & COX-2 in inflammation, (iii) Different approaches used to improve gastric tolerance i.e. chemical manipulation,
formulation & co-administration, development of non specific (COX-1 & COX-2 inhibitors) and specific (COX-2 inhibitors) inflammation
inhibitors, and development of inflammation inhibitors having a mode of action other than COX-1 & COX-2 inhibition. We have
also focused on the safety of COX-2 inhibitors and the synthesis of heterocyclic compounds and their role as inflammation
inhibitors. 相似文献
999.
The goal of the present study is to test the hypothesis that LPA induces proliferation of astrocytes in hippocampus in vivo via phosphorylation of ERK 1/2. We first characterized the expression of GFAP, a special marker fiber protein of astrocytes,
in brain slices after direct injection of LPA into hippocampus by immunohistochemistry, and found that LPA induced a remarkable
proliferation of astrocytes. Then double-lablled immunofluorescence was used to detect GFAP and phosphorylation ERK 1/2 (p-ERK
1/2), LPA induced an immediate (10 min) and transient (<30 min) phosphorylation of ERK 1/2, and sequence sustained activation
of ERK 1/2 was observed, which last for at least 3 weeks after injection of LPA. Reactions are inhibited by U0126, a specific
pharmacological mitogen-activated protein kinase (MEK) inhibitor. Laser confocal scanning was used to study spatial relationship
of p-ERK and astrocytes. Amazingly, the early (<7 days) phosphorylation of ERK 1/2 is not expressed in astrocytes but in area
where neurons and/or in other cell type(s) occupied, expression of p-ERK 1/2 in astrocytes is not detected until 14 days after
LPA injection and lasts for at least 3 weeks. Taken together, these data suggest that LPA play an important role in proliferation
of astrocytes through phosphorylation of ERK 1/2 in hippocampus. It provides further proof for the functions of LPA in CNS
injury, and may contribute to clinical therapy for relative diseases. 相似文献
1000.
新型含氟聚芳醚酮的合成与表征 总被引:10,自引:0,他引:10
聚芳醚酮具有很高的热稳定性和优良的电性能及机械性能 ,已经被广泛应用于宇航、电子及核能等高技术领域 [1] .氟元素的引入可以降低材料介电常数、折光指数和吸水率 ,提高热稳定性、溶解性和阻燃性 ,增加材料透明度 ,使这类聚合物在光电子、光学和微电子等应用领域的研究倍受关注 [2~ 4 ] .本文在合成含三氟甲基苯侧基的聚芳醚酮 [5] 的基础上 ,设计并合成了新型的含氟量更高的单体和聚合物 ,并对其性能进行了初步研究 .1 实验部分1 .1 试剂与仪器 [3,5 -二 (三氟甲基 ) ]苯代对苯醌 (自制 ) ;锌粉 ,A.R.级 ,天津化学试剂一厂产品 ;… 相似文献