Struktur und synthese von flavonol-triosiden aus rhamnus-arten

By synthesis and ¹³C-NMR spectroscopic investigations of rhamnocitrin-, rhamnazin- and rhamnetin - 3 - O - [O - α - l - rhamnopyranosyl - (1 → 4) - O - α - l - rhamnopyranosyl - (1 → 6)] β - d - galactopyranosides and of rhamnocitrin - 3 - O - [O - α - l - rhamnopyranosyl - (1 → 3) - O - α - l - rhamnopyranosyl - (1 → 6)] - β - d - galactopyranoside (rhamnocitrin - 3 - O - β - rhamnisoide) it was proved that all naturally occurring flavonoltriosides, so far isolated from different Rhamnus species, contain the sugar-moiety rhamninose. Thus it was shown that catharticin (rhamnocitrin - 3 - O - β - rhamninoside) is identical with alaternin and xanthorhamnin A (rhamnetin - 3 - O - β - rhamninoside) with xanthorhamnin B, whereas xanthorhamnin C is rhamnazin - 3- O - β - rhamninoside. From Rhamnus saxatilis JACQ., ssp. saxat. a new flavonol - acetyl - trioside was isolated and the structure by MS and ¹³C-NMR spectroscopic means elucidated to be the rhamnetin - 3 - O - [O - α - l - rhamnopyranosyl - (1 → 3) - O - (4 - O - acetyl - ) - α - l - rhamnopyranosyl - (1 → 6)] - β - d - galactopyranoside.     

Isolierung und Struktur von langkettigen Alkylphenolen und -pyrocatecholen aus Plectranthus albidus (Labiatae)

Isolation and Structure of Long-Chain Alkylphenols and -catechols from Plectranthus albidus (Labiatae) From the title plant, a series of even-numbered long-chain, phenol- or pyrocatechol-derived 1-arylalkan-5-ones was isolated by classical chromatography and preparative reversed phase HPLC. By chemical and spectroscopic methods, including coupled chromatographic techniques (GC/MS/FT-IR, HPLC/MS), their structures were established to be 1-(4′-hydroxyphenyl)tetradecan-5-one ( 2a ), 1-(4′-hydroxyphenyl)hexadecan-5-one ( 2b ), 1-(4′-hydroxyphenyl)octadecan-5-one ( 2c ), and (Z)-1-(4′-hydroxyphenyl)octadec-13-en-5-one ( 2d ); (E,E)-1-(3′,4′-dihydroxyphenyl)deca-1,3-dien-5-one ( 1a ), 1-(3′,4′-dihydroxyphenyl)dodecan-5-one ( 3a ), 1-(3′,4′-dihydroxyphenyl)-tetradecan-5-one ( 3b ), 1-(3′,4′-dihydroxyphenyl)hexadecan-5-one ( 3c ), 1-(3′,4′-dihydroxyphenyl)octadecan-5-one ( 3d ), 1-(3′,4′-dihydroxyphenyl)icosan-5-one ( 3e ), and (Z)-1-(3′,4′-dihydroxyphenyl)octadec-13-en-5-one ( 3f ). In vitro, the compounds show significant antioxidant activity, the inhibitory concentration of the most potent one, 1a , being slightly lower than for 2-(tert-butyl)-4-methoxyphenol (BHA) and 2,6-di(tert-butyl)-4-methylphenol (BHT) in the Fe²⁺-catalysed autooxidation of linoleic acid, whereas the acitivities of phenols 2a–d are in the same order of magnitude as α-tocopherol.     

Struktur und stereochemie eines sesquiterpen-esters und dreier sesquiterpen-alkaloide von Celastrus paniculatus Willd

A new sesquiterpene ester (Malkangunin) and three sesquiterpene alkaloids (Celapanin, Celapanigin, Celapagin) were isolated from Celastrus paniculatus Willd. The complete structure and stereochemistry of Malkangunin, a sesquiterpene tetra-ol of the β-dihydroagarofurane type two of whose hydroxyls being esterified with acetic and benzoic acids, is discussed. The alkaloids described here are derived from a new sesquiterpene tetra-ol (Celapanol) which is alternately esterified with acetic, benzoic, nicotinic and β-furoic acids.     

Die verwendung von diisobutylaluminiumhydrid zur stereoselektiven synthese von tertiären (e)-2-alkenylaminen, (e)-2-alken-4-inylaminen und 2(

In exploring versatile synthetic routes to (E)-allylamine derivatives with antimycotic properties, a new method has been found in the trans-reduction of tertiary 2-alkinylanunes by diisobutylaluminum hydride (DIBAH). The stereoselectivity of this reaction, which is in contrast to the well-known cis-hydroalumination of disubstituted alkynes, and the regioselectivity have been studied in detail. Tertiary 2-alkinylamines 1 were generally reduced to (E)-2-alkenylamines 2 in toluene at 40°, and tertiary 2,4-alkadiynylamines 3 yielded a mixture of(E)-2-alken-4-ynylamines 4 and 2(E),4(Z)-alkadienylamines 5 in high stereochemical purity. This reduction was clearly different with respect to reactivity and selectivity in comparison with other reactions also proceeding via trans-hydroalumination, namely the lithium aluminum hydride reduction of α-hydroxyacetylenes and the reaction of alkynes with LiAlH(iso-Bu)₂(n-Bu). Tertiary 6-hydroxy-2, 4-alkadiynylamines 10 were reduced to 6-hydroxy-2(E)-alken-4-ynylamines 11 with diisobutylaluminum hydride, whereas on treatment with lithium aluminum hydride 6-hydroxy-4(E)-alken-2-ynylamines 12 were obtained. LiAlH (iso-Bu)₂(n-Bu) did not react with 2-alkinylamine 1a and the 2,4-alkadiynylamine 3a was only monohydroaluminated without discrimination of the two acetylene groups. A possible mechanism for the diisobutylaluminum hydride reduction of 2-alkinylamines is presented.     

Carotinoide aus marinen Schwämmen (Porifera): Isolierung und Struktur von sieben Hauptcarotinoiden aus Agelas schmidtii

Carotenoids from Marine Sponges (Porifera): Isolation and Structure of the Seven Main Carotenoids from Agelas schmidtii The following carotenoids were identified in the marine sponge Agelas schmidtii: α-carotene ((6′R)-β, ε-carotene ( 1 )), isorenieratene (φ,φ-carotene ( 2 )), trikentriorhodin (3,8-dihydroxy-κ,χ-caroten-6-one ( 3 )) and zeaxanthin ((3R, 3′R)-β, β-carotene-3, 3′-diol ( 4 )). In addition, three previously unknown carotenoids called agelaxanthin A, B and C were isolated. Spectroscopical and chemical structure elucidation showed agelaxanthin A to be (3 R)-β, φ-caroten-3-ol ( 6 ) and agelaxanthin C to be a methoxy-19,3′,8′-trihydroxy-7,8-didehydro-β, κ-caroten-6′-one ( 7 ) with the methoxy group at C (2), C (3) or C (4). The limited data on age-laxanthin B were compatible with the structure of a 19-O-methyl derivative of agelaxanthin C.     

Darstellung und Struktur von Tetraethylcyclotetraarsoxan-Komplexen von Kupfer(I)-Halogeniden

Preparation and Structure of Tetraethylcyclotetraarsoxane Complexes of Copper(I) Halides The polymeric complexes [Cu₄Cl₄{cyclo-(C₂H₅AsO)₄}₃]_n ( 1 ), [Cu₃Br₃{cyclo-(C₂H₅AsO)₄}₂]_n ( 2 ) and [Cu₆I₆{cyclo-(C₂H₅AsO)₄}₃]_n ( 3 ) were prepared by the reaction of (C₂H₅AsO)_n and CuX (X = Cl, Br, I) in acetonitrile and characterised by X-ray analysis. All three complexes contain only tetramers (C₂H₅AsO)₄ as ligands, in which the As₄O₄ ring systems coordinate between two and four Cu-atoms. In each case one As₄O₄ ring with a crown-shaped conformation is observed, which coordinates either four (in 1 ) or three (in 2 and 3 ) axially sited Cu-atoms. In addition there are further (C₂H₅AsO)₄ ligands, which display either a boat-chair- (in 1 ) or a twist-chair-conformation (in 1–3 ). The individual building units are connected to one another via Cu? X? Cu bridges (in 2 and 3 ) and/or centrosymmetric As₄O₄ ring systems (in 1–3 ) into chain ( 1 ) or layer structures ( 2 und 3 ).     

Isolierung und Struktur von Pteridinen (Lumazinen) aus Russula sp. (Täublinge; Basidiomycetes)

Isolation and Structure Elucidation of Pteridines (Lumazines) from Russula sp. (Basidiomycetes) Extensive chromatogaphic separations and spectroscopic investigations have led to the isolation and identification of several water-soluble pteridines from Russula sp., the so-called russupteridines, namely: 1-(5-amino-2-6-dioxo-1,2,3,6-tetrahydeopyrimidin-4-yl)amino-1-deoxy-D -ribitol ( 1 ; a pro-lumazine; first identification in a basidiomycete(; l-deoxy-l-(6-methyl-2-4,7-trioxo-1,2,3,4,7,8-hexahydro-pteridin-8-yl)-D -ribitol ( 3 ) and l-deoxy-1-(2,4,7-trioxo-1,2,3,4,7,8-hexahydeopteridin-8-yl)-D -ribitol ( 4 ); both compounds found for the first time in higher fungi; they belong to the components with the strongest violet-blue fluorescence in Russula sp.; riboflavine ( 6 ; now recognized as an important yellow colorant in a great many of Russula sp.); russupteridine-yellow I (= l-(6-amino-7-(N-fromylimino)-2,4-dioxo-1,2,3,4,7,8-hexahydropteridin-8-yl)-1-deoxy-D -ribitol; 5 ; a component with very strong fluorescence; the first derivative of the novel 6,7-diamino-lamazine); russupteridine-yellow IV (= l-deoxy-1-)(2,6,8-trioxo-2,4,5,6,7,8-hexahydro-1H-imidazolo[4,5-g]pteridin-4-yl)-D -ribitol (7)). Two further yellow russupteridines (yellow II and Yellow V) with very strong fluorescence have been isolated and characterized.     

Struktur und Eigenschaften von makroskopischen Einkristallen aus Polymeren mit konjugierten Bindungssystemen

Zusammenfassung Beider Polymerisation von Einkristallen aus Monomeren mit konjugierten Dreifachbindungen entstehen Einkristalle von Polymeren, deren Hauptkette im Kristall gestreckt vorliegt und aus miteinander konjugierten, alternierend angeordneten Doppel- und Dreifachbindungen besteht. Die Strukturdaten von zwei ausgewählten Polymeren werden diskutiert. Charakteristisch ist die Periodizität in Kettenrichtung von ca. 4.9 A und die Anordnung aller Bindungen der Hauptkette in einer Ebene.Die polymeren Einkristalle zeigen negative thermische Ausdehnung in Kettenrichtung und ausgeprägte Spaltbarkeit in bevorzugten Ebenen parallel zur Kettenrichtung. Die konjugierte Hauptkette wirkt als starker Chromophor. Die Kristalle sind daher tief gefärbt und besitzen dichroische Absorptionsbanden bei ca. 490–550 nm. Aufgrund der Molekülstruktur ist elektrische Leitfähigkeit zu erwarten. Die ge-messenen Dunkel- und Photoleitfähigkeiten sind jedoch geringer als erwartet und liegen bei 40 °C in der Größenordnung von 10^–10 bis 10^–14 Ohm^–1cm^–1 mit Aktivierungsenergien von ca. 1 eV in Abhängigkeit von der Struktur der Seitengruppen an der konjugierten Hauptkette. Die elektrische Leitfähigkeit ist richtungsabhängig.Auch die Polymerisation der Monomeren wirft einige festkörperphysikalische Fragen auf, wie z. B. die Abhängigkeit der Reaktion von der Defektstruktur der Monomerkristalle und die Frage nach dem Mechanismus der Photoanregung in einer kristallinen Matrix.

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Summary Solid-state polymerization of monomers with conjugated triple-bonds gives rise to single-crystals of polymers consisting of extended chain molecules which are build up of conjugated alternating double-and triple-bonds. The structural data of two selected polymers are discussed. Characteristically, the chain repeat is ca. 4.9 Å and all the bonds of the backbone are located in the same plane. The polymer single crystals exhibit negative thermal expansion in chain direction and show characteristic cleavage behaviour with regard to planes parallel to the main-chain. Because the conjugated main-chain acts as a strong chromophor, the crystals are deeply coloured and show absorption bands around 490 to 550 nm with strong dichroism. From the molecular structure electrical conductivity of the crystals is expected. The values of dark- and photoconductivity measured so far are, however, much smaller then expected. At 40 °C conductivity values of ca. 10^–10 to 10^–14ohm^–1 cm^–1 are found depending to some extent on the structure of the side groups of the polymer back-bone (activation energy ca. 1 eV). The conductivity is found to be anisotropic.The polymerization itself is found to be an interesting phenomenon from the point of view of solid state physics. Some unsolved problems relate to the dependence of the reaction on the defect structure of the monomer crystals and to the mechanism of excitation of monomer molecules inside the matrix of the crystals.

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Mit 21 Abbildungen und 3 Tabellen     

Phosphor- und schwefelsubstituierte allene in der synthese I: einfache synthese von β-ketophosphonaten aus 1-alkin-3-olen

Allenic phosphonates, readily accessible from 1-alkin-3-ols, the addition products of 1-alkines to aldehydes or ketones, can be transformed to β-ketophosphonates by nucleophilic addition of diethylamine and subsequent hydrolysis of the formed enamines.     

Darstellung und Struktur von Antimon(III)-tris(thiophosphinaten)

Preparation and Structure of Antimony (III) Tris (thiophosphinates) The title compounds are formed by the reaction of Sb(CH₃COO)₃ with thiophosphinic acids R₂P(?S)OH (R = CH₃ cyclo-C₆H₁₁, C₆H₅). The crystal and molecular structures of Sb((cyclo-C₆H₁₁)₂POS)₃ and Sb((C₆H₅)₂POS)₃ have been determined by single crystal X-ray methods. Sb^III is pyramidally coordinated to the oxygen atoms of the R₂POS ligands through short (primary) bonds with a mean length of 203 pm. The Sb? S distances of the mainly chelating ligands vary between 300 and 320 pm (secondary bonds). The lone electron pair is stereochemically active.     

Si-Kernresonanzspektren und synthese von bromdisilanen und ioddisilanen

The syntheses of Bromodisilanes Br_nSi₂H_6−n and Iododisilanes I_nSi₂H_6−n (n = 1, 2, 3, 4, 5), starting from caryldisilanes Ar_nSi₂H_6−n (Ar = phenyl, -naphthyl, mesityl) are reported. The ²⁹Si-NMR-spectra of all compounds, including ²⁹Si²⁹Si-coupling constants, have been measured.

Zusammenfassung

Ausgehend von Aryldisilanen ArS₂H_6−n, (Ar = Phenyl, -Naphthyl, Mesityl) wurden die Bromdisilane Br_nSi₂H_6−n, und Ioddisilane I_nSi₂H_6−n, (n = 1, 2, 3, 4, 5) synthetisiert. Die ²⁹Si-NMR-Spektren aller Verbindungen, (eingeschlossen ²⁹Si²⁹Si-Kopplungskonstanten) wurden vermessen.     

Synthese und Struktur der Kronenetherkomplexe von Kaliumhexachlorodipalladat(II) und -diplatinat(II)

Synthesis and Structure of Crown Ether Complexes of Potassium Hexachlorodipalladate(II) and -diplatinate(II) K₂[MCl₄] (M ? Pd, Pt) reacts with an excess of crown ether 18-crown-6 in water to give the crown ether complexes of potassium hexachlorodipalladate(II) and -diplatinate(II) [K(18-cr-6)]₂[M₂Cl₆] (M ? Pd, 1 ; M ? Pt, 3 ), respectively, and in methylene chloride to give those of potassium tetrachloropalladate(II) and -platinate(II) [K(18-cr-6)]₂[MCl₄] ( 1 ) (M ? Pd, 2 ; M ? Pt, 4 ), respectively. 1 - 4 are characterized by microanalysis, NMR (¹H, ¹³C), and vibrational spectroscopy. The X-ray structure analyses of the isotypic complexes 1 (P2₁/c; a = 10,9678(8), b = 8,2991(7), c = 22,469(2) Å, β = 98,523(5)°; Z = 2) and 3 (P2₁/c; a = 10,934(3), b = 8.376(3), c = 22,410(5) Å, β = 98,77(3)°; Z = 2) reveal [M₂Cl₆]^2? anions of nearly D_2h symmetry and [K(18-cr-6)]⁺ cations, in which the distance of K⁺ to the mean plane of the crown ether defined by its six oxygen atoms amounts to 0,830(4) Å in 1 and 0,821(2) Å in 3 , respectively. There are tight contacts between cations and anions (d(K-Cl): 3,341(2)/3,260(2) Å ( 1 ); 3,348(4)/3,259(4) Å ( 3 )).     

Synthese und Struktur von Au(OTeF5)3

Syntheses and Structure of Au(OTeF₅)₃ Stable and crystalline Au(OTeF₅)₃ is prepared from AuF₃ and B(OTeF₅)₃. The crystal structure analysis of the monoclinic single crystals, space group C2/c, a = 1893.8(4), b = 847.3(2), c′ = 564.6(2) pm, β = 94.30(5), gave the OTeF₅ positions, but the gold positions only in a statistical manner. Interpretation of weak diffuse super structure reflections resulted in a three times magnified c-axis and produced molecular units of the X₂AuX₂AuX₂ type. This is the first time that bridging OTeF₅ ligands have been observed.     

Synthese und Struktur von Vanadium(III)- und Vanadium(IV)-silanolaten

Synthesis and Structures of Vanadium(III) and Vanadium(IV) Silanolates The syntheses of the new and partially known vanadium(III)-silanolate complexes [{V(OSiMe^t₂Bu)₃}₂(THF)] ( 1 ), [Li(THF)₂V(OSiMe^t₂Bu)₄] ( 2 ), [V(OSiMe^t₂Bu)(lut)] ( 3 ), V(OSiPh₃)₃(THF)₃ ( 4 ), [Li(THF)₄][V(OSiPh₃)₄](THF)₂ ( 5 ), [Li(DME)VMes(OSiMe^t₂Bu)₃] ( 7 ), [Li(THF)₄][VMes · (OSiPh₃)₃] ( 8 ), [Li(THF)₄][VMes₃(OSiMe^t₂Bu)] ( 9 ), and Na[VMes₃(OSiPh₃)](THF)₄ ( 10 ) as well as the vanadium(IV) compounds [V(OSiPh₃)₄] ( 6 ), [VMes₃(OSiMe^t₂Bu)] ( 11 ) and [VMes₃(OSiPh₃)] ( 12 ) are reported. In most cases the vanadium atom displays a coordination number of four. The dimeric structure of 1 with coordination numbers of four and five, respectively, has been deduced from molecular mass measurements, mass spectrometry and its magnetic properties. The crystal structures of compounds 2 , 4 , 5 , 9 and 11 were resolved. Complex 2 resembles a bridged contact ion pair in which both metal centres are in a tetrahedral coordination environment. In 4 the ligands are arranged trigonal bipyramidally with the THF molecules in the axial positions. Complexes 5 and 9 crystallize in separated ion paires with the vanadium in a tetrahedral coordination sphere. The crystal structure of 11 is analogous to that of 9 but with consequences due to the higher oxidation state. Oxidation of the vanadates(III), e. g. 5 , 9 and 10 , yields the corresponding vanadium(IV) compounds 6 , 11 and 12 .     

Über die Struktur von Imidazolin- und Imidazolidin-Derivaten aus 2-Amino-2-desoxy-hexosen

In earlier publications [1] [2] [3] [4] a pyranoid structure has been proposed for the sugar moiety of imidazoline and imidazolidine derivatives from D -glucosamine. But by NMR.-spectra and periodate oxidation the sugar moiety of these compounds and of similar derivatives from other 2-amino-2-deoxy-sugars is now shown to be of furanoid structure.     

Synthese,Eigenschaften und Struktur von cis-Dihydridoazido-tris(triphenylphosphino)-iridium

Synthesis, Properties, and Structure of cis-Dihydrido Azido Tris(triphenylphosphino) Iridium cis-IrH₂(N₃)(PPh₃)₃ is formed from IrCl₃(PPh₃)₃ and NaN₃ in alcohol. The solvent transfers the hydride ions whereby aldehyde is formed. The creme-colored cis-IrH₂(N₃)(PPh₃)₃ is a diamagnetic low-spin complex. Exposure to light yields H₂ and Ir(N₃)(PPh₃)₃ in a reversible process. The cis position of the hydrido ligands is confirmed by the i.r. and H-N.M.R. spectra. Cis-IrH₂(N₃)(PPh₃)₃ crystallizes in the monoclinic system with the space group P2₁/c. The crystal structure exhibits isolated octahedral complexes, in which one hydrido ligand is located trans to the azido group. The other one being trans to one of the phosphine ligands.     

Struktur und thermischer Abbau von Bis (1,3-diketonato) cobalt-bisimidazolen

Structure and Thermal Degradation of Bis(1,3-diketonato)cobaltbisimidazoles The crystal structure of Co(bzac)₂(HIm)₂. 2MeOH ( I ) and Co(acac)₂(HIm)₂ ( II ) were determined by x-ray diffraction. II : triclinic, space group P1 , Z = 2, a = 746.3(1), b = 948.2(1), c = 1396.7(2)pm, α = 85.18(1)°, β = 88.96(1)°, γ = 80.72(1)°, R = 3.0% for a total of 2194 observed reflections. I : monoclinic, P2₁/c, Z = 2, a = 964.2(3), b = 864.5(2), c = 1769.8(4)pm, β = 98.87(2)°, R = 4.7% for a total of 967 observed reflections. In both compounds centrosymmetric molecules with two bidentate diketonato groups and two imidazole ligands in trans-position are present. The molecules of II are linked by N? H…?O-bridges within layers, while in the lattice of I by the interaction with methanol molecules N-H…?O-H…?O-bridges are formed. The nature of the H-bridges is the deciding factor for the first step of the thermal degradation of the complexes. The N-H…?O-bridges of II relieves the change of the acidic protons of the imidazole to the acetylacetonato ligands. Therefore in the first step acetylacetone is eliminated. No such bridges are present in the complex I . Therefore, in the first step, imidazole and methanol are removed. On heating in O-donor solvents the reaction of I is quite analogous, and this is the reason for the application of this complex as a latent initiator of the epoxide polymerisation.