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ECSOC-15

A special issue of Molecules (ISSN 1420-3049).

Deadline for manuscript submissions: closed (31 May 2012) | Viewed by 43118

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Departamento de Química Orgánica, Universidad de Santiago de Compostela, Facultad de Ciencias-Campus de Lugo, Alfonso X el Sabio, 27002 Lugo, Spain
Interests: synthesis of compounds with biologic activity; synthesis of compounds with interest for agro-food field; solation, structural determination and synthesis of natural products; microwave organic reactions enhancement
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For more information on The 15th International Electronic Conference on Synthetic Organic Chemistry (ECSOC-15), please go to: http://www.sciforum.net/conf/ecsoc-15

Published Papers (6 papers)

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300 KiB  
Article
1H-Nuclear Magnetic Resonance Analysis of the Triacylglyceride Composition of Cold-Pressed Oil from Camellia japonica
by Carmen Salinero, Xesús Feás, J. Pedro Mansilla, Julio A. Seijas, M. Pilar Vázquez-Tato, Pilar Vela and María J. Sainz
Molecules 2012, 17(6), 6716-6727; https://doi.org/10.3390/molecules17066716 - 04 Jun 2012
Cited by 27 | Viewed by 6799
Abstract
Camellia japonica (CJ) has oil-rich seeds, but the study of these oils has received little attention and has mainly focused only on their health properties. In the present work the relative composition of the fatty acid (FA) components of the triglycerides in cold-pressed [...] Read more.
Camellia japonica (CJ) has oil-rich seeds, but the study of these oils has received little attention and has mainly focused only on their health properties. In the present work the relative composition of the fatty acid (FA) components of the triglycerides in cold-pressed oil from CJ is studied by 1H-NMR. The results obtained were: 75.75%, 6.0%, 0.17% and 18.67%, for oleic, linoleic, linolenic and saturated FA respectively. Levels of C18 unsaturated FA found in CJ oil were similar to those reported for olive oils. We also checked the possibility of using 13C-NMR spectroscopy; however, the results confirmed the drawback of 13C over 1H-NMR for the study of FA components of CJ triglycerides due to its low gyromagnetic ratio and its very low natural abundance. Full article
(This article belongs to the Special Issue ECSOC-15)
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469 KiB  
Article
Calculation of the Stabilization Energies of Oxidatively Damaged Guanine Base Pairs with Guanine
by Masayo Suzuki, Katsuhito Kino, Masayuki Morikawa, Takanobu Kobayashi, Rie Komori and Hiroshi Miyazawa
Molecules 2012, 17(6), 6705-6715; https://doi.org/10.3390/molecules17066705 - 01 Jun 2012
Cited by 18 | Viewed by 5920
Abstract
DNA is constantly exposed to endogenous and exogenous oxidative stresses. Damaged DNA can cause mutations, which may increase the risk of developing cancer and other diseases. G:C-C:G transversions are caused by various oxidative stresses. 2,2,4-Triamino-5(2H)-oxazolone (Oz), guanidinohydantoin (Gh)/iminoallantoin (Ia) and spiro-imino-dihydantoin [...] Read more.
DNA is constantly exposed to endogenous and exogenous oxidative stresses. Damaged DNA can cause mutations, which may increase the risk of developing cancer and other diseases. G:C-C:G transversions are caused by various oxidative stresses. 2,2,4-Triamino-5(2H)-oxazolone (Oz), guanidinohydantoin (Gh)/iminoallantoin (Ia) and spiro-imino-dihydantoin (Sp) are known products of oxidative guanine damage. These damaged bases can base pair with guanine and cause G:C-C:G transversions. In this study, the stabilization energies of these bases paired with guanine were calculated in vacuo and in water. The calculated stabilization energies of the Ia:G base pairs were similar to that of the native C:G base pair, and both bases pairs have three hydrogen bonds. By contrast, the calculated stabilization energies of Gh:G, which form two hydrogen bonds, were lower than the Ia:G base pairs, suggesting that the stabilization energy depends on the number of hydrogen bonds. In addition, the Sp:G base pairs were less stable than the Ia:G base pairs. Furthermore, calculations showed that the Oz:G base pairs were less stable than the Ia:G, Gh:G and Sp:G base pairs, even though experimental results showed that incorporation of guanine opposite Oz is more efficient than that opposite Gh/Ia and Sp. Full article
(This article belongs to the Special Issue ECSOC-15)
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246 KiB  
Article
Synthesis and Antibacterial Activity of Some Heterocyclic Chalcone Analogues Alone and in Combination with Antibiotics
by Thanh-Dao Tran, Thi-Thao-Nhu Nguyen, Tuong-Ha Do, Thi-Ngoc-Phuong Huynh, Cat-Dong Tran and Khac-Minh Thai
Molecules 2012, 17(6), 6684-6696; https://doi.org/10.3390/molecules17066684 - 01 Jun 2012
Cited by 90 | Viewed by 12702
Abstract
A series of simple heterocyclic chalcone analogues have been synthesized by Claisen Schmidt condensation reactions between substituted benzaldehydes and heteroaryl methyl ketones and evaluated for their antibacterial activity. The structures of the synthesized chalcones were established by IR and 1H-NMR analysis. The [...] Read more.
A series of simple heterocyclic chalcone analogues have been synthesized by Claisen Schmidt condensation reactions between substituted benzaldehydes and heteroaryl methyl ketones and evaluated for their antibacterial activity. The structures of the synthesized chalcones were established by IR and 1H-NMR analysis. The biological data shows that compounds p5, f6 and t5 had strong activities against both susceptible and resistant Staphylococcus aureus strains, but not activity against a vancomycin and methicillin resistant Staphylococcus aureus isolated from a human sample. The structure and activity relationships confirmed that compounds f5, f6 and t5 are potential candidates for future drug discovery and development. Full article
(This article belongs to the Special Issue ECSOC-15)
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593 KiB  
Article
Synthesis, Property Characterization and Photocatalytic Activity of the Novel Composite Polymer Polyaniline/Bi2SnTiO7
by Yunjun Yang and Jingfei Luan
Molecules 2012, 17(3), 2752-2772; https://doi.org/10.3390/molecules17032752 - 06 Mar 2012
Cited by 32 | Viewed by 5583
Abstract
A novel polyaniline/Bi2SnTiO7 composite polymer was synthesized by chemical oxidation in-situ polymerization method and sol-gel method for the first time. The structural properties of novel polyaniline/Bi2SnTiO7 have been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron [...] Read more.
A novel polyaniline/Bi2SnTiO7 composite polymer was synthesized by chemical oxidation in-situ polymerization method and sol-gel method for the first time. The structural properties of novel polyaniline/Bi2SnTiO7 have been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray spectrometry. The lattice parameter of Bi2SnTiO7 was found to be a = 10.52582(8) Å. The photocatalytic degradation of methylene blue was realized under visible light irradiation with the novel polyaniline/Bi2SnTiO7 as catalyst. The results showed that novel polyaniline/Bi2SnTiO7 possessed higher catalytic activity compared with Bi2InTaO7 or pure TiO2 or N-doped TiO2 for photocatalytic degradation of methylene blue under visible light irradiation. The photocatalytic degradation of methylene blue with the novel polyaniline/Bi2SnTiO7 or N-doped TiO2 as catalyst followed first-order reaction kinetics, and the first-order rate constant was 0.01504 or 0.00333 min−1. After visible light irradiation for 220 minutes with novel polyaniline/Bi2SnTiO7 as catalyst, complete removal and mineralization of methylene blue was observed. The reduction of the total organic carbon, the formation of inorganic products, SO42− and NO3−, and the evolution of CO2 revealed the continuous mineralization of methylene blue during the photocatalytic process. The possible photocatalytic degradation pathway of methylene blue was obtained under visible light irradiation. Full article
(This article belongs to the Special Issue ECSOC-15)
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320 KiB  
Article
Oxidation of 2-Hydroxynevirapine, a Phenolic Metabolite of the Anti-HIV Drug Nevirapine: Evidence for an Unusual Pyridine Ring Contraction
by Alexandra M. M. Antunes, Muna Sidarus, David A. Novais, Shrika G. Harjivan, Pedro P. Santos, João L. Ferreira da Silva, Frederick A. Beland and M. Matilde Marques
Molecules 2012, 17(3), 2616-2627; https://doi.org/10.3390/molecules17032616 - 05 Mar 2012
Cited by 9 | Viewed by 5665
Abstract
Nevirapine (NVP) is an anti-HIV drug associated with severe hepatotoxicity and skin rashes, which raises concerns about its chronic administration. There is increasing evidence that metabolic activation to reactive electrophiles capable of reacting with bionucleophiles is likely to be involved in the initiation [...] Read more.
Nevirapine (NVP) is an anti-HIV drug associated with severe hepatotoxicity and skin rashes, which raises concerns about its chronic administration. There is increasing evidence that metabolic activation to reactive electrophiles capable of reacting with bionucleophiles is likely to be involved in the initiation of these toxic responses. Phase I NVP metabolism involves oxidation of the 4-methyl substituent and the formation of phenolic derivatives that are conceivably capable of undergoing further metabolic oxidation to electrophilic quinoid species prone to react with bionucleophiles. The covalent adducts thus formed might be at the genesis of toxic responses. As part of a program aimed at evaluating the possible contribution of quinoid derivatives of Phase I phenolic NVP metabolites to the toxic responses elicited by the parent drug, we have investigated the oxidation of 2-hydroxy-NVP with dipotassium nitroso-disulfonate (Frémy’s salt), mimicking the one-electron oxidation involved in enzyme-mediated metabolic oxidations. We report herein the isolation and full structural characterization of a 1H-pyrrole-2,5-dione derivative as a major product, stemming from an unusual pyridine ring contraction. Full article
(This article belongs to the Special Issue ECSOC-15)
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424 KiB  
Article
Preparation of Novel meta- and para-Substituted N-Benzyl Protected Quinuclidine Esters and Their Resolution with Butyrylcholinesterase
by Ines Primožič, Marijana Bolant, Alma Ramić and Srđanka Tomić
Molecules 2012, 17(1), 786-795; https://doi.org/10.3390/molecules17010786 - 16 Jan 2012
Cited by 4 | Viewed by 5812
Abstract
Since the optically active quinuclidin-3-ol is an important intermediate in the preparation of physiologically or pharmacologically active compounds, a new biocatalytic method for the production of chiral quinuclidin-3-ols was examined. Butyrylcholinesterase (BChE; EC 3.1.1.8) was chosen as a biocatalyst in a preparative kinetic [...] Read more.
Since the optically active quinuclidin-3-ol is an important intermediate in the preparation of physiologically or pharmacologically active compounds, a new biocatalytic method for the production of chiral quinuclidin-3-ols was examined. Butyrylcholinesterase (BChE; EC 3.1.1.8) was chosen as a biocatalyst in a preparative kinetic resolution of enantiomers. A series of racemic, (R)- and (S)-esters of quinuclidin-3-ol and acetic, benzoic, phthalic and isonicotinic acids were synthesized, as well as their racemic quaternary N-benzyl, meta- and para-N-bromo and N-methylbenzyl derivatives. After the resolution, all N-benzyl protected groups were successfully removed by catalytic transfer hydrogenation with ammonium formate (10% Pd-C). Hydrolyses studies with BChE confirmed that (R)-enantiomers of the prepared esters are much better substrates for the enzyme than (S)-enantiomers. Introduction of bromine atom or methyl group in the meta or para position of the benzyl moiety resulted in a considerable improvement of the stereoselectivity compared to the non-substituted compounds. Optically pure quinuclidin-3-ols were prepared in high yields and enantiopurity by the usage of various N-benzyl protected groups and BChE as a biocatalyst. Full article
(This article belongs to the Special Issue ECSOC-15)
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