| | 1 | Author
| Thorsten Kemmer, Hans Brockmann, Nikolaus Risch | Requires cookie* | | | Title
| Die Einzelkomponenten der Bacteriophäophorbidmethylester von Bacteriochlorophyll c und d The Individual Components of Bacteriophaeophorbide Methyl Esters from Bacteriochlorophyll c and d  | | | | Abstract
| The preparative column chromatographic separation on small grained silica gel of the bacteriophaeophorbide-c-and -d-methyl esters into their homologous and isomeric components is described. The influence of particular regions of the molecule, which carry different alkyl-substituents, on the chromatographic separability is selectively enhanced through the variation of the eluent. Mass and ifl NMR spectra of the pure components are discussed. Einführung Von den in Chlorobiaceae vorkommenden Bacterio-chlorophyllen c und d ist schon seit den Untersuchun-gen von Holt und Mitarbeitern [1, 2] bekannt, daß sie in der Natur als komplexe Gemische isomerer und homologer Verbindungen vorkommen. Eine Trennung in die einzelnen Komponenten ist für die aus den Chlorophyllen durch Hydrolyse leicht zu-gänglichen Phäophorbide durch Verteilen zwischen Ether und Salzsäure an Celite-Säulen beschrieben worden [3-5]. Wieweit dabei die einzelnen Kompo-CH3 nenten wirklich in reiner Form erhalten wurden, ist heute schwer zu überprüfen; bei den sich anschlie-ßenden physikalischen und chemischen Untersu-chungen wurden nämlich zum Teil widersprüchliche Resultate erhalten [6, 7]. Dennoch konnten Holt und Mitarbeiter [1, 2] aus ihren Untersuchungs-ergebnissen die Konstitutionsformeln 1 und 2 für die Bacteriochlorophylle c und d ableiten, die trotz zeitweiliger Kritik [7-9] durch neuere Arbeiten nur bestätigt wurden [10, 11]. Chlorobium-Bacteriochlorophylle cd) und d(2) | | | |
Reference
| Z. Naturforsch. 34b, 633—637 (1979); eingegangen am 10. August 1978 | | | |
Published
| 1979 | | | |
Keywords
| Chromatography, Separation, Bacteriochlorophylls, X H NMR | | | |
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| default:Reihe_B/34/ZNB-1979-34b-0633.pdf | | | | Identifier
| ZNB-1979-34b-0633 | | | | Volume
| 34 | |
| 3 | Author
| Jochen Ellermann, Martin Lietz, Peter Merbach, Gerhard Thiele, Gerd Zoubek | Requires cookie* | | | Title
| Chemie polyfunktioneller Liganden, 53 [1] Über methyl-substituierte Triarsa-trioxa-, Triarsa-trithia- und Triarsa-triaza-adamantane und über den stark aufgeweiteten Adamantan-Käfig im Schwefel-Derivat Chemistry of Polyfunctional Ligands, 53 [1] About Methyl-substituted Triarsa-trioxa-, Triarsa-trithia-and Triarsa-triaza-adamantanes and about the Strongly Spread Adamantane Cage in the Sulfur Derivative | | | | Abstract
| The reaction of l,l,l-tris(diiodarsinomethyl)ethane, CH3C(CH2Asl2)3 (1), with H2O, H2S and CH3NH2 in THF gives the adamantane cage compounds CH3C(CH2ASO)3 (4), CH3C(CH2ASS)3 (5) and CH3C(CH2ASNCH3)3 (6) in high yields. The crystal structure of 5 has been determinated by X-ray diffraction. The unit cell (space group P2i/w) contains 4 isolated molecules in a cubic closest packing. The heteroadamantane 5 has an enlarged cage structure with extremely spread C-C(H2)-As bond angles of 124° at the methylene carbon atoms. Some pharmacological properties of the adamantane derivatives 4 and 5 have been studied. All compounds have been characterized by mass spectrometry and infrared, Raman and X H NMR spectroscopy. | | | |
Reference
| Z. Naturforsch. 34b, 975—982 (1979); eingegangen am 26. März 1979 | | | |
Published
| 1979 | | | |
Keywords
| Heteroadamantanes, Vibrational Spectra, Mass Spectra, X H NMR, Molecular and Crystal Structure | | | |
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| default:Reihe_B/34/ZNB-1979-34b-0975.pdf | | | | Identifier
| ZNB-1979-34b-0975 | | | | Volume
| 34 | |
| 4 | Author
| Heinz Falk, Klaus Thirring | Requires cookie* | | | Title
| On the Chemistry of Pyrrole Pigments, XXXIV [1] On the Configurations and Conformations of Diastereomeric N-Methyl-O-methyl-bilatrienes-abc | | | | Abstract
| of the aetiobiliverdin-IV-y-lactimether yields a lactam-N-methylated derivative the structure of which was proven by an ether cleavage and iH NMR spectro-scopy. The configuration (Z,Z,Z) was deduced from iHNMR experiments. Photo-isomerization exclusively forms the (E,Z,Z) diastereomer. By conformational analysis using the LIS technique and correlations of UV-VIS spectra and PPP-type calculations a more or less helical arrangement for the two diastereomers was confirmed. The twisting is maximal at the methine single bond adjacent to the site of N-methylation, the overall geometry seems to be much more distorted than the non methylated derivatives. | | | |
Reference
| Z. Naturforsch. 34b, 1600—1605 (1979); eingegangen am 13. Juli 1979 | | | |
Published
| 1979 | | | |
Keywords
| X H NMR, UV-VIS, Lanthanide Ion Induced Shifts, PPP-Calculations, Conformational Analysis Methylation | | | |
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| default:Reihe_B/34/ZNB-1979-34b-1600.pdf | | | | Identifier
| ZNB-1979-34b-1600 | | | | Volume
| 34 | |
| 5 | Author
| MohamedHilmy Elnagdi, Mohamed Ezzat, KamalUsef Kandeel, Sadek | Requires cookie* | | | Title
| Reactions with Cyclic Amidenes III: Synthesis of Some New Fused Pyrazole Derivatives | | | |
Reference
| Z. Naturforsch. 34b, 275—279 (1979); received August 28 1978 | | | |
Published
| 1979 | | | |
Keywords
| Diazobetaienes, Dipolarcycloaddition, Pryazolo[4, 3-c]-l, 2, 3, 4-tetrazines, Ethoxycarbonyl Isothiocyanate, X H NMR | | | |
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| default:Reihe_B/34/ZNB-1979-34b-0275.pdf | | | | Identifier
| ZNB-1979-34b-0275 | | | | Volume
| 34 | |
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