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Desulfurization of Dibenzothiophene and Oxidized Dibenzothiophene Ring Systems  [PDF]
Diego P. Morales,Alexander S. Taylor,Steven C. Farmer
Molecules , 2010, DOI: 10.3390/molecules15031265
Abstract: Lithium, used in conjunction with sodium metal, produces a high yield of biphenyl when reacted with dibenzothiophene, dibenzothiophene sulfoxide or dibenzothiophene sulfone.
Multicomponent Click Synthesis of New 1,2,3-Triazole Derivatives of Pyrimidine Nucleobases: Promising Acidic Corrosion Inhibitors for Steel  [PDF]
Rodrigo González-Olvera,Araceli Espinoza-Vázquez,Guillermo E. Negrón-Silva,Manuel E. Palomar-Pardavé,Mario A. Romero-Romo,Rosa Santillan
Molecules , 2013, DOI: 10.3390/molecules181215064
Abstract: A series of new mono-1,2,3-triazole derivatives of pyrimidine nucleobases were synthesized by one-pot copper(I)-catalyzed 1,3-dipolar cycloaddition reactions between N-1-propargyluracil and thymine, sodium azide and several benzyl halides. The desired heterocyclic compounds were obtained in good yields and characterized by NMR, IR, and high resolution mass spectrometry. These compounds were investigated as corrosion inhibitors for steel in 1 M HCl solution, using electrochemical impedance spectroscopy (EIS) technique. The results indicate that these heterocyclic compounds are promising acidic corrosion inhibitors for steel.
The simulation of the formation of dibenzothiophene and dibenzofuron
Yanqing Xia,Chunjiang Wang,Qianxiang Meng
Chinese Science Bulletin , 1998, DOI: 10.1007/BF03183515
Abstract: The results of simulation indicate that biphenyl (BIP) is one of the original materials of dibenzothiophene (SF) and dibenzofuron (OF). It has the fundamental structure of SF and OF. As the radicals that attract electron, its two aromatic nucleuses influence each other, which make the α-H active. The strong electronegative sulphur or oxygen atoms attack the two places of the two aromatic nucleuses, seize the hydrogens and form H2S or H2O, the other sulphur or oxygen atoms attacking the two places which have lost hydrogens can put up a bridge and make the BIP molecule which can freely turn become a stable SF or OF molecule. So SF and OF have no definite relation with fluorene (F).
Inhibition of Human Neutrophil Elastase by Pentacyclic Triterpenes  [PDF]
Li Feng, Xiaoyu Liu, Weiliang Zhu, Fujiang Guo, YingchunWu, Rui Wang, Kaixian Chen, Cheng Huang, Yiming Li
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082794
Abstract: Scope Inhibiting human neutrophil elastase (HNE) is a promising strategy for treating inflammatory lung diseases, such as H1N1 and SARS virus infections. The use of sivelestat, the only clinically registered synthesized HNE inhibitor, is largely limited by its risk of organ toxicity because it irreversibly inhibits HNE. Therefore, potent reversible HNE inhibitors are promising alternatives to sivelestat. Methods and Results An in vitro HNE inhibition assay was employed to screen a series of triterpenes. Six pentacyclic triterpenes, but not tetracyclic triterpenes, significantly inhibited HNE. Of these pentacyclic triterpenes, ursolic acid exhibited the highest inhibitory potency (IC50 = 5.51 μM). The HNE inhibitory activity of ursolic acid was further verified using a mouse model of acute smoke-induced lung inflammation. The results of nuclear magnetic resonance and HNE inhibition kinetic analysis showed that the pentacyclic triterpenes competitively and reversibly inhibited HNE. Molecular docking experiments indicated that the molecular scaffold, 28-COOH, and a double bond at an appropriate location in the pentacyclic triterpenes are important for their inhibitory activity. Conclusion Our results provide insights into the effects of pentacyclic triterpenes on lung inflammatory actions through reversible inhibition of HNE activity.
Biologically active pentacyclic triterpenes and their current medicine signification
Jiri Patocka
Journal of Applied Biomedicine , 2003,
Abstract: Pentacyclic triterpenes are produced by arrangement of squalene epoxide. These compounds areextremely common and are found in most plants. There are at least 4000 known triterpenes. Manytriterpenes occur freely but others occur as glycosides (saponins) or in special combined forms.Pentacyclic triterpenes have a wide spectrum of biological activities and some of them may beuseful in medicine. The therapeutic potential of three pentacyclic triterpenes – lupeol, betuline andbetulinic acid – is discussed in this paper. Betulinic acid especially is a very promising compound.This terpene seems to act by inducing apoptosis in cancer cells. Due to its apparent specificity formelanoma cells, betulinic acid seems to be a more promising anti-cancer substance than drugs liketaxol.
Metabolism of the dibenzothiophene by Pseudomonas stutzeri PLC 16
Bracho G,Mariángela; Querales,Luis; Aiello Mazzarri,Cateryna; Soto,Luz Marina;
Revista Técnica de la Facultad de Ingeniería Universidad del Zulia , 2007,
Abstract: in this work, the degradation of dibenzothiophene (dbt) by pseudomonas sutzeri plc 16 was evaluated by the study of the bacterial growth kinetic in the presence of this hydrocarbon as only carbon source, and the analysis of its metabolites of degradation by uv spectrophotometry. the kinetic growth of pseudomonas sutzeri plc 16 was determined by the quantification of the bacteria number through the ephifluorescence microscopy technique. the bacterial oxidation of the dbt was evaluated through the appearance of the 3-hydroxy-2-formyl benzothiophene and trans-4-[2-(3-hydroxy)-thionaphthenyle]-2- oxo-3 butenoic acid, which are the main metabolites in the degradation of this compound. as result, a rate growth of the culture of 0.828 h-1 with a time of duplication of 0.837 hours were observed. the dibenzothiophene oxidation was verified observing the appearance of the metabolite accumulation maximum peaks at 48 and 96 hours, a period that agreed with the logarithmic growth phase of the culture, condition that evidence the oxidation of the dibenzothiophene by p. stutzeri plc16 and the potential of this strains for future biotechnological applications.
Pentacyclic triterpenoid ketones in peat from Gannan Marsh, China
Yi Duan
Chinese Science Bulletin , 2001, DOI: 10.1007/BF03187024
Abstract: Abundant terrigenous triterpenoid ketones and a series of hopanoid ketones were detected in a peat sample from the recent Gannan Marsh. The identifications of pentacyclic triterpenoid ketones are discussed in detail. Based on the compositional features of pentacyclic triterpenoid ketones in the sample, it is proposed that terrigenous triterpenoid kentones originate directly from organisms or are diagenetic oxidation products of their alcohols, and hopanoid ketones are formed from hopanoids (e.g. hopanoid alcohols and hopenes) by chemical and biochemical processes. These data provide evidence for the applied studies of pentacyclic triterpenoid ketones as biomarker compounds.
CT&F - Ciencia, Tecnología y Futuro , 1998,
Abstract: three methods for the removal of sulfurfrom dibenzothiophene were evaluated using biocatalytic processes. the methods were a microbial, an enzymatic and a combined one that involves a previous enzymatic oxidation followed by microbial degradation. the byconversion was evaluated over the molecular dibenzothiophene model, obtaining higher byconversion percentages through the combined method. the microorganisms used in this study correspond to several colombian indigenous strains isolated by direct methods from natural sources, and using a standard strain as positive control. all strains have shown sulfur removal capacity, and organic solvent tolerance. the enzyme used was a hemoprotein with peroxidase activity, cytochrome c, obtained from equine heart.
In vitro Cytotoxic Pentacyclic Triterpenoids of Newbouldia laevis
P.A. Onocha,D.A. Okorie,H.C. Krebs,B. Meier
Research Journal of Medical Sciences , 2012, DOI: 10.3923/rjmsci.2011.330.335
Abstract: Bioactivity directed fractionation afforded four cytotoxic constituents from the bioactive methanolic leaf extract (LD50 30 μg mLG1) of Newbouldia laevis (Bignoniaceae) collected from Ibadan, Nigeria. Four pentacyclic triterpenoids namely 2α, 3β, 19α-trihydroxy-12-ursen-28-oic acid, 3β, 19α-dihydroxy-12-ursen-28-oic acid, 3β-hydroxy-12-ursen-28-oic acid, 3β-hydroxy 12-oleanen-28-oic acid were found to be the cytotoxic principles. These compounds demonstrated significant cytotoxicity in vitro against ST-57 brain tumor transformed fibroblasts with LD50 ranging from 0.4 μg mLG1 (compound 1) to 4 μg mLG1 (compound 4). These ursene and oleanene type triterpenoids are encountered for the first time in this plant. The structures of these compounds were established by spectral data.
Journal of the Chilean Chemical Society , 2011, DOI: 10.4067/S0717-97072011000300011
Abstract: triazole and fused heterocyclic triazole derivatives like schiff bases, thiadiazoles, thiadiazepine, thiadiazine etc. were synthesized and characterized by ir, ms and 1h nmr. the triazole derivatives were evaluated for their antibacterial activity against the gram-positive bacteria b. megaterium and s. aureus, the gram-negative bacteria e. aerogenes and p. aeruginosa using dmso as a solvent.
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