scholarly journals Spectrometric Study of the Nitrile-Ketenimine Tautomerism

2009 ◽  
Vol 2009 ◽  
pp. 1-18 ◽  
Author(s):  
Hebe Saraví Cisneros ◽  
Sergio Laurella ◽  
Danila L. Ruiz ◽  
Agustín Ponzinibbio ◽  
Patricia E. Allegretti ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Mass Spectrum ◽  
Magnetic Resonance ◽  
Mass Spectra ◽  
Spectrometric Study ◽  
Mass Spectral ◽  
Ion Fragmentation ◽  
Nuclear Magnetic Resonance Spectra ◽  
Amination Product

Mass spectrometry is used to evaluate the occurrence of the nitrile-ketenimine tautomerism. Mass spectra of two differently substituted nitriles, ethyl-4,4-dicyano-3-methyl-3-butenoate and diethyl-2-cyano-3-methyl-2-pentenodiate are examined looking for common mass spectral behaviors. Ion fragmentation assignments for specific tautomers allow to predict the presence of the corresponding structures. Additionally, the mass spectrum and nuclear magnetic resonance spectra of ethyl-4,4-dicyano-2,2-diethyl-3-methyl-3-butenoate and that of the corresponding amination product support the occurrence of the ketenimine tautomer in the equilibrium.

Mass Spectral Study of the Occurrence of Tautomeric Forms of Thiohydantoins

2007 ◽  
Vol 13 (4) ◽  
pp. 291-306 ◽  
Author(s):  
Patricia E. Allegretti ◽  
M. de las Mercedes Schiavoni ◽  
Celia Guzmán ◽  
Agustín Ponzinibbio ◽  
Jorge J.P. Furlong
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Mass Spectrum ◽  
Magnetic Resonance ◽  
Mass Spectra ◽  
Carbonyl Groups ◽  
Mass Spectral ◽  
Tautomeric Forms ◽  
Nuclear Magnetic Resonance Spectra ◽  
Mass Spectral Study

Mass spectrometry is used to evaluate the occurrence of thio-enol structures among the several possible tautomers of thiohydantoins and dithiohydantoins. Mass spectra of differently-substituted thiohydantoins are examined looking for common mass spectral behaviors to be predicted. Ion fragmentations from specific tautomers allow the most stable thio-enol structure for both type of compounds. The mass spectrum of the alkylation product of 5,5-dimethyldithiohydantoin and the nuclear magnetic resonance spectra of the alkylation products of both 2-thiohydantoin and dithiohydantoin support the fact that the most likely thio-enol structure is determined by the presence of one or two thio-carbonyl groups in the hydantoin molecule.

Natural occurrence of archaetidic acid and caldarchaetidic acid (di- and tetra-ether analogues of phosphatidic acid) in the archaebacterium Methanohacterium thermautotrophicum

1990 ◽  
Vol 68 (1) ◽  
pp. 91-95 ◽  
Author(s):  
Masateru Nishihara ◽  
Yosuke Koga
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Ether Lipid ◽  
Natural Occurrence ◽  
Phospholipid Biosynthesis ◽  
Nuclear Magnetic Resonance Spectra ◽  
Minor Phospholipid ◽  
A Minor

A minor phospholipid designated as PL5, assumed to be a precursor of phospholipid biosynthesis, was isolated from Methanohacterium thermautotrophicum. The structures of this lipid and another closely related phospholipid (PL4) were elucidated by infrared spectra, fast atom bombardment mass spectra, 31P-nuclear magnetic resonance spectra, and chemical and enzymatic analyses. These lipids were identified as archaetidic acid (PL5) and caldarchaetidic acid (PL4) (diether and tetraether analogues of phosphatatidic acid, respectively).Key words: archaetidic acid, caldarchaetidic acid, Methanohacterium thermautotrophicum, archaebacterium, ether lipid.

Taxonomy and chemistry of a new fungus from bark beetle infested Pinus contorta var. latifolia. Part 2. Arthrographol, the metabolite inhibitory to Ophiostoma clavigerum

1990 ◽  
Vol 36 (2) ◽  
pp. 83-85 ◽  
Author(s):  
William A. Ayer ◽  
Koohei Nozawa
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Mass Spectrum ◽  
Magnetic Resonance ◽  
Pinus Contorta ◽  
Antifungal Compound ◽  
Compound Structure ◽  
Nuclear Magnetic Resonance Spectra ◽  
Blue Stain Fungi ◽  
Blue Stain

The isolation and structure determination of arthrographol (1) is described. This substituted dihydrobenzofuran is the compound responsible for the antagonism shown by the newly described fungus Arthrographis pinicola Sigler and Yamaoka towards some blue stain fungi. The 1H and 13C nuclear magnetic resonance spectra, infrared and ultraviolet spectra, and the mass spectrum of arthrographol and its diacetyl derivative are reported. The inhibitory activity of arthrographol against Ophiostoma clavigerum (≡Ceratocystis clavigera) is described. Arthrographol, a new natural product, appears to be a norheptaketide related to known benzofurans of fungal origin. Key words: antifungal compound, structure of arthrographol, norheptaketide, blue stain fungus, Arthrographis pinicola.

Separation and Identification of Bridgehead-Substituted Methyl and Ethyl Adamantanes

1968 ◽  
Vol 22 (2) ◽  
pp. 115-120 ◽  
Author(s):  
R. W. Warren ◽  
Abraham Schneider ◽  
E. J. Janoski
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Gas Chromatography ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Adamantane Derivatives ◽  
Saturated Hydrocarbons ◽  
Aluminum Halide

A combination of gas chromatography, infrared and nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry was used to characterize the products obtained from aluminum halide-catalyzed isomerizations of tricyclic saturated hydrocarbons. Six compounds were isolated and identified as methyl and ethyl bridgehead-substituted adamantane derivatives. In addition to supplying evidence pertinent to the structural proof of these derivatives, the data provide useful correlations between infrared, NMR, and mass spectra and methyl and ethyl bridgehead substitution of the adamantane nucleus. A complex splitting pattern which was observed in the NMR spectra of the ethyl-substituted derivatives was shown to be due to the unique A2B3 splitting of the bridgehead-ethyl group.

The Nematocidal Principles of Tagetes Roots

1963 ◽  
Vol 16 (3) ◽  
pp. 475 ◽  
Author(s):  
DHS Horn ◽  
JA Lamberton
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Mass Spectra ◽  
Nuclear Magnetic Resonance Spectra ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The structure assigned to the liquid nematocidal principle of Tagetes roots 5-(3-buten-1-ynyl)-2,2'-bithienyl (II), by Uhlenbroek and Bijloo, has been confirmed by studying the mass spectra and nuclear magnetic resonance spectra of (II) and its hydrogenation products. α-Terthienyl (I) and (II) have also been isolated from fresh roots of T. minuta (T. glandulifera).

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