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Your search keyword '"Francisco Arnaldo Viana"' showing total 4 results
Start Over Author "Francisco Arnaldo Viana" Journal magnetic resonance in chemistry
4 results on '"Francisco Arnaldo Viana"'

1. 1 H and 13 C NMR assignments for two new cordiaquinones from roots of Cordia leucocephala

Author

Edilberto R. Silveira, Raimundo Braz-Filho, Otília Deusdênia L. Pessoa, Maria Conceição M. Torres, Francisco Arnaldo Viana, Jaécio Carlos Diniz, Maria Aparecida Medeiros Maciel, and Odaci Fernandes de Oliveira

Subjects
biology, Stereochemistry, Chemistry, Proton NMR, General Materials Science, General Chemistry, Nuclear magnetic resonance spectroscopy, Boraginaceae, Carbon-13 NMR, Cordia, biology.organism_classification, Two-dimensional nuclear magnetic resonance spectroscopy, Heteronuclear single quantum coherence spectroscopy
Abstract

From the roots of Cordia leucocephala (Boraginaceae), two new meroterpenoid naphthoquinones, 6-[10-(12,12-dimethyl-13alpha-hydroxy-16-methenyl-cyclohexyl)ethyl]-1,4-naphthalenedione (cordiaquinone L) and 5-methyl-6-[10-(12,12-dimethyl-13beta-hydroxy-16-methenyl-cyclohexyl)methyl-1,4-naphthalenedione (cordiaquinone M) were isolated. Their structures were elucidated after detailed 1D and 2D NMR (COSY, HSQC, HMBC and NOESY) data analyses and comparison with literature data for analogous compounds.

Published
2008
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2. Complete1H and13C NMR assignments for two new monodesmoside saponins fromPentaclethra macroloba(Willd.) Kuntze

Author

Otília Deusdênia L. Pessoa, Edson Rodrigues-Filho, Yvone B.M. Pouliquen, Raimundo Braz-Filho, Gilvandete M. P. Santiago, Manoel Andrade-Neto, and Francisco Arnaldo Viana

Subjects
Carbon Isotopes, Stem bark, Sapogenins, food.ingredient, Molecular Structure, Stereochemistry, Chemistry, Electrospray ionization, Molecular Sequence Data, Fabaceae, General Chemistry, Saponins, Carbon-13 NMR, Triterpenoid, food, Carbohydrate Sequence, Plant Bark, Proton NMR, Pentaclethra macroloba, General Materials Science, Spectral data, Nuclear Magnetic Resonance, Biomolecular, Two-dimensional nuclear magnetic resonance spectroscopy, Hydrogen
Abstract

A detailed NMR study and full assignments of the 1H and 13C spectral data for two novel triterpenoid saponins isolated from the stem bark of Pentaclethra macroloba (Willd.) Kuntze are described. Their structures were established using a combination of 1D and 2D NMR techniques including 1H,1H-COSY, TOCSY, NOESY, gs-HMQC and gs-HMBC, and also electrospray ionization mass spectrometry and chemical methods. The structures were established as 3beta-O-([O-beta-D-glucopyranosyl-(1--2)-O-beta-D-glucopyranosyl-(1--4)-O-beta-D-glucopyranosyl-(1--3)-O-alpha-L-rhamnopyranosyl-(1--2)]-[O-beta-D-glucopyranosyl-(1--3)-O-beta-D-glucopyranosyl-(1--4)])-alpha-L-arabinopyranosylhederagenin (1) and 3beta-O-)[O-beta-D-glucopyranosyl-(1--2)-O-beta-D-glucopyranosyl-(1--4)-O-beta-D-glucopyranosyl-(1--3)-O-alpha-L-rhamnopyranosyl-(1--2)]-[O-beta-D-glucopyranosyl-(1--3)-O-beta-D-glucopyranosyl-(1--4)])-alpha-L-arabinopyranosyloleanolic acid (2).

Published
2004
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3. Structure elucidation and total assignment of1H and13C NMR data for a new bisdesmoside saponin fromCordia piauhiensis

Author

Raimundo Braz-Filho, Renata P. Santos, Telma L. G. Lemos, Francisco Arnaldo Viana, Otília Deusdênia L. Pessoa, and Edilberto R. Silveira

Subjects
chemistry.chemical_classification, biology, Stereochemistry, Saponin, General Chemistry, Cordia, Carbon-13 NMR, biology.organism_classification, chemistry.chemical_compound, chemistry, Ursolic acid, Proton NMR, Organic chemistry, General Materials Science, Methanol, Bisdesmoside, Two-dimensional nuclear magnetic resonance spectroscopy
Abstract

Extensive 1D (1H NMR, HBBD-13C NMR, DEPT-13C NMR) and 2D (COSY, TOCSY, NOESY, HMQC and HMBC) NMR analysis was used to characterize the structure of a new bisdesmoside saponin isolated from the methanol extract of stems of Cordia piauhiensis Fresen as 3β-O-[α-L-rhamnopyranosyl-(1 2)-β-D-glucopyranosyl]ursolic acid 28-O-[β-D-glucopyranosyl-(1 6)-β-D-glucopyranosyl] ester. Copyright © 2003 John Wiley & Sons, Ltd.

Published
2003
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4. Characterization of two minor saponins fromCordia piauhiensis by1H and13C NMR spectroscopy

Author

Francisco Arnaldo Viana, Otília Deusdênia L. Pessoa, Edilberto R. Silveira, Renata P. Santos, Raimundo Braz-Filho, and Telma L. G. Lemos

Subjects
Magnetic Resonance Spectroscopy, Stereochemistry, Electrospray ionization, Molecular Sequence Data, Molecular Conformation, Cordia, chemistry.chemical_compound, 13c nmr spectroscopy, Organic chemistry, General Materials Science, Oleanolic acid, Carbon Isotopes, biology, General Chemistry, Nuclear magnetic resonance spectroscopy, Reference Standards, Saponins, Carbon-13 NMR, biology.organism_classification, carbohydrates (lipids), Carbohydrate Sequence, chemistry, Proton NMR, Protons, Two-dimensional nuclear magnetic resonance spectroscopy
Abstract

A careful NMR analysis with full assignment of the 1H and 13C spectral data for two minor saponins isolated from stems of Cordia piauhiensis is reported. These saponins were isolated by high-performance liquid chromatography and characterized as 3beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]pomolic acid 28-O-[beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl] ester (1) and 3beta-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl]oleanolic acid 28-O-[beta-D-xylopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 6)-beta-D-glucopyranosyl] ester (2). Their structures were established using a combination of 1D and 2D (1H, 1H-COSY, TOCSY, NOESY, gs-HMQC and gs-HMBC) NMR techniques, electrospray ionization mass spectrometry and chemical evidence.

Published
2005
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