Die Verluste an Bariumsulfat bei der gewichtsanalytischen Bestimmung

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Den giftigen Bestandtheil der Ricinussamen

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Den Zuckernachweis mit der Phenylhydrazinprobe

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NMR-spektroskopische Untersuchungen an Mercaptophosphazenen. I. Verlauf der Reaktion von Natriumethylmercaptid mit Hexachlorocyclotriphosphazatrien bzw. Octachlorocyclotetraphosphazatetraen

N.M.R. Spectroscopic Investigations of Thiophosphazenes. I. Reactions of Sodium Ethylthiolate with Hexachlorocyclotriphosphazatriene and Octachlorocyclotetraphosphazatetraene By reactions of hexachlorocyclotriphosphazatriene with an excess of sodium ethylthiolate as a suspension in ether all of the possible geminal derivatives N₃P₃Cl_6?n(SEt)_n; n = 1–6, are formed in different quantities. Products from reactions of octachlorocyclotetraphosphazatetraene with sodium ethylthiolate, N₄P₄Cl_8?n(SEt)_n, likewise contain all of the geminally substituted derivatives up to n = 8 with the exception of the derivatives with n = 1 and n = 7. Compounds with n = 3, 4, or 5 exist in two geminal isomers respectively. Nongeminal ethylthiochlorophosphazenes were not found by any reaction. The formed compounds were isolated by chromatographic methods and studied by ³¹P n.m.r. spectroscopy.     

Metallorganische verbindungen der lanthaniden. : III. Dicyclopentadienyllanthanid-triphenylgermane bzw.-stannane

Dicyclopentadienyl-erbium and -ytterbium chloride react with lithium triphenyl-germane or -stannane under formation of dicyclopentadienylerbiumtriphenylgermane, -triphenylstannane and dicyclopentadienylytterbium-triphenylstannane.     

Den Mechanismus der Methylenblaureduktion in Milch

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Den Gehalt an Sulfhydrylgruppen

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Jodbestimmung mit der Apparatur von Grote-Kreke1er bzw. Wurzschmitt-Zimmermann

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Massenspektren der von Aminosäuren bzw. Peptiden abgeleiteten Triazin-Derivate

A mass spectrometric study of about 30 triazine derivatives from amino acids and peptides is reported. These derivatives incorporated the C-terminal of amino acids and peptides in the ring. In contrast to the mass spectra of amino acids and peptide esters reported previously, they always showed characteristic fragments, denoting the presence of the terminal triazine ring. By using this peak as a marker, it is easy to estimate the C-terminal of peptides. In dipeptides, the N-terminal and C-terminal are determined simultaneously.     

Den Nachweis von Blutfarbstoff durch einen an der Grenze des sichtbaren Violett liegenden Absorptionsstreifen

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Mit der Analyse von Wismutlegierungen mit Uran- und Neodym- bzw. Praseodymgehalten

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Zur Addition von Phenylisocyanat bzw. Phenylisothiocyanat an 4-Hydroxycumarin

Zusammenfassung 4-Hydroxycumarin (1) reagiert mit Phenylisocyanat zum 3-Carboxanilido-4-hydroxycumarin (3). Phenylisothiocyanat addiert sich an1 zum 3-Thiocarboxanilido-4-hydroxycumarin (8).

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Addition of phenyl isocyanate and phenyl isothiocyanate, resp., on 4-hydrocumarin

4-Hydroxy-coumarin (1) reacts with phenylisocyanate to 3-carboxanilido-4-hydroxy-coumarin (3). Phenylisothiocyanate is added to1 yielding 3-thiocarboxanilido-4-hydroxy-coumarin (8).

     

Den Einflu? der Polarisationsrichtung auf den Verlauf von Stromspannungskurven an station?ren Elektroden

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Den histoehemischen und papierchromatographischen Nachweis von Inhaltsstoffen der Kartoffelknolle

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Die R?ntgenstrukturanalyse der Additionsverbindungen von 1,4-Dioxan mit Oxalylchlorid bzw. -bromid

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Katalysatordesaktivierungen bei der Acetylen-Polymerisation mit Titanocen- bzw. Zirconocen-Komplexen des Bis(trimethylsilyl)acetylens

Desactivation of Catalysts in the Polymerization of Acetylene by Bis(trimethylsilyl)acetylene Complexes of Titanocene or Zirconocene Unexpected inactive byproducts were observed in the catalytic polymerization of acetylene using metallocene alkyne complexes Cp₂M(L)(η²-Me₃SiC₂SiMe₃), 1 : M = Ti, without L; 2 : M = Zr, L = thf. The reaction of 1 was investigated in detail by NMR to give quantitatively at –20 °C the titanacyclopentadiene Cp₂Ti–CH=CH–C(SiMe₃)=C(SiMe₃) ( 3 ). Around 0 °C 3 starts to rearrange to yield the dihydroindenyl complex 4 via coupling of one Cp-ligand with the titanacyclopentadiene. In the reaction of 2 under analogous conditions a zirconacyclopentadiene Cp₂Zr–CH=CH–C(SiMe₃)=C(SiMe₃) ( 5 ) and the dimeric complex [Cp₂Zr(C(SiMe₃)=CH(SiMe₃)]₂[μ-σ(1,2)-C≡C] ( 6 ) were observed. Whereas 5 decomposes to a mixture of unidentified paramagnetic species, 6 was isolated and investigated by NMR spectroscopy and X-ray analysis. In the reaction of rac-(ebthi)Zr(η²-Me₃SiC₂SiMe₃) (ebthi = ethylenbistetrahydroindenyl) with 2-ethynyl-pyridine the complex rac-(ebthi)ZrC(SiMe₃)=CH(SiMe₃)](σ-C≡CPy) 7 was obtained, which was investigated by an X-ray analysis.     

Synthese und Charakterisierung der 8 isomeren,im Ring B mono- bzw. dihydroxylierten Royleanone

Synthesis and Characterization of the 8 Stereoisomeric Royleanones with One or Two Hydroxy Groups in Ring B The partial syntheses of 6α, 7α-dihydroxyroyleanone ( 6a ), 6α, 7β-dihydroxyroyleanone ( 7a ) and 6β, 7β-dihydroxyroyleanone ( 9a ) are described. Thus, all in ring B mono- and dihydroxylated royleanones are now known (see [2–11]), being fully characterized by extensive spectroscopic, chiroptic and chromatographic (HPLC.) methods. An opening of the epoxyroyleanone 11a yields cis- and trans-diols together with their corresponding mono- and di-O-acetyl derivatives. We postulate a reversible addition of the acetate ion at C(8) of the quinone system, followed by a neighbouring group participation of this O-acetyl group.