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  • 1980-1984  (8,286)
  • Inorganic Chemistry  (3,506)
  • Physics  (2,657)
  • Biochemistry and Biotechnology  (1,710)
  • Gas chromatography  (412)
  • Nuclear reactions
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 142 (1984), S. 165-169 
    ISSN: 1432-1076
    Keywords: Adrenal gland neoplasms ; Urine steroids ; Gas chromatography ; Mass spectrometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Steroid excretion in urine of 12 infants with virilising adrenal tumours has been determined using gas chromatography. In six children, (Group A, five female, one male) aged 2.8–5.3 years, very high urinary excretions of 17 oxosteroids (〉40 μmol/24 h) were largely accounted for by dehydroepiandrosterone (DHA). In one of the girls, the pattern of steroids excreted in urine was similar to that of newborn infants, with high excretions of 16-oxygenated derivatives of DHA. The histology of this tumour suggested a neoplasia of fetal-type adrenocortical cells. Very large tumours were found in three of the infants, two of whom have died and one has multiple metastases. From the other three children, small, well-encapsulated adenomas were successfully removed. Six children (Group B), had moderately elevated 17-oxosteroid exrretions (8–17 μmol/ 24 h). In five of these cases (four female, one male) aged 0.8–5 years, 11β-hydroxyandrosterone was a consistently prominent urinary steroid. In one boy, aged 7.7 years, 17-oxosteroid excretion was 15 μmol/24 h and the major steroids in urine were metabolites of pregnenolone. These six children have survived with no clinical evidence of recurrent tumour. The in vivo functional activities of the tumours can be deduced from the different profiles of steroids in urine. These have revealed heterogeneous patterns of steroid biosynthesis.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 55 (1984), S. 70-75 
    ISSN: 1432-0738
    Keywords: Soman ; Gas chromatography ; Mass spectrometry ; Cholinesterases ; Aliesterase ; Phosphorylphosphatase ; Toxicity ; Stereoselectivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The fate of the four stereoisomers of soman [0-(1,2,2-trimethylpropyl)-methyl-fluoro phosphonate] has been studied a) in vivo in mouse blood and liver after IP injection of 0.75 × LD50 Rc- and Sc-soman respectively, and b) in vitro upon incubation wih acetyl- und pseudocholinesterase, aliesterase and phosphorylphosphatase. The analytical method used is based on gas chromatography — mass spectrometry with deuterated internal standard. Most soman disappeared very rapidly from blood and liver. In liver, SCRP and RCRP, the two isomers that preferentially react with cholinesterase, could be detected. The level of SCRP, which was higher than that of RCRP, could be followed for 17–18 h. In blood only SCRP could be detected. The amounts found were fairly constant during the time period 2 min to 4h, and it could even be detected 17–18 h after soman administration.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 55 (1984), S. 272-275 
    ISSN: 1432-0738
    Keywords: 2-Ethoxyethanol ; Teratogen ; Adsorption ; Desorption ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A gas Chromatographic procedure for the determination of 2-ethoxyethanol (C2H5OCH2CH2OH) was developed by using the general principles of analysis of solvent vapors. 2-Ethoxyethanol was sampled by adsorbing on activated carbon. It was desorbed with carbon disulfide plus 2-propanol (0.5%). The analytical column was packed with 10% free fatty acid phase on Chromosorb-P AW. The analysis was conducted at 130° C isothermal using a flame ionization detector. Addition of 2-propanol (0.5%) to carbon disulfide improved (P≤0.01) desorption of 2-ethoxyethanol adsorbed on activated carbon. The mean desorption efficiency of carbon disulfide plus 2-propanol (0.5%) was 87.9±2.86% (n=15). Based on a 101 air sample and detector sensitivity of 2×10−10AFS, the calculated limit of detection of 2-ethoxyethanol was 0.1 ppm. The precision (coefficient of variation) for this analytical procedure was 3.34% (n=12). In conclusion, 2-ethoxyethanol adsorbed on activated carbon can be desorbed with carbon disulfide plus 2-propanol (0.5%). Subsequently the desorbed 2-ethoxyethanol can be analyzed by gas chromatographic identification on 10% FFAP using a flame ionization detector.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 327 (1984), S. 260-265 
    ISSN: 1432-1912
    Keywords: Amitriptyline ; Imipramine ; Clomipramine ; Demethylated metabolites ; Free fractions ; Serum ; Equilibrium dialysis ; Gas chromatography ; Binding parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The plasma protein binding of amitriptyline, imipramine, clomipramine, and their primary demethylated metabolites were studied by means of a method combining dialysis and gas chromatography. Equilibrium in dialysis of serum containing amitriptyline and its metabolite nortriptyline was attained in about 0.5 h with the drug dissolved in the serum compartment, and in about 2 h with the drug passing from the buffer to the serum compartment. The calculation of free fractions was influenced by variations with dialysis time in the volumes of serum and buffer. Increase of pH in serum increased the protein binding of the weakly basic drugs studied, and made the Donnan distribution effects more pronounced. At pH 7.4, the Donnan effect was negligible. Binding parameters for the 6 tricyclic antidepressant substances studied were estimated for the binding to α1-acid glycoprotein and for total binding in serum. For α1-acid glycoprotein, the k-values ranged from 1·105 to 8·105 M−1, and for pooled serum from 0.4·105 to 8·105 M−1. The determined number of binding sites on the α1-acid glycoprotein was, on average 0.87 for the 6 substances. In serum, the binding capacity was 2–14 times the concentration of α1-acid glycoprotein.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Esterification in aqueous solution ; n-Butyl esters of C2−C16 dicarboxylic acids ; Dicarboxylic acid analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary C2−C16 dicarboxylic acids were esterified in aqueous solution in the presence of sulfuric acid. Esterification in water/n-butanol mixtures with mole ratios between 0.02 and 2.53 can be utilized for the quantitative determination of the dicarboxylic acids by gas chromatography. The presence of water does not interfere at water/n-butanol mole ratios below 0.27. For mole ratios above 0.27 anhydrous sodium sulfate has been used for binding the water. The mole ratio range was 0.25–0.75 for anhydrous sodium sulfate/water, and 0.32–1.3 for sulfuric acid/anhydrous sodium sulfate.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 18 (1984), S. 663-667 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Gas solubilities ; Enthalpies of solution ; Polar solutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The gas-liquid chromatographic method has been used to determine the solubilities and partial molar enthalpies of solution of the gases H2S, CO2 and COS in four polar solvents. The results agree well with literature values obtained using conventional techniques, with the one exception of H2S in N-methyl-2-pyrrolidinone. In this case there is some evidence for the occurrence of adsorption at the gas-liquid interface.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Esterification in aqueous solution ; n-Butyl esters of aromatic polycarboxylic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The direct esterification and gas chromatographic analysis of aromatic carboxylic acids as n-butyl esters is described. Derivatization is performed in aqueous solution with n-butanol in the presence of sulfuric acid. The butyl esters of benzoic, phthalic, hemimellitic, trimellitic, trimesic and pyromellitic acids permit their gas chromatographic separation from each other and from fatty acids and alipatic dicarboxylic acids. At mole ratios of [H2O]/ [n-BuOH]≤0.04 the water present does not interfere with the esterification reaction. At mole ratios above 0.04 anhydrous sodium sulfate is used for binding the water, at mole ratios of [Na2SO4 anh.]/[H2O]=0.25–0.75.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 18 (1984), S. 202-204 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Polysiloxane stationary phases ; Heat of adsorption ; Heat of solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The changes in the heat of solution of polar compounds and xylene isomers in methylsilicone fluid OV-101 deposited on Chromosorb W AW DMCS were studied. It was shown that the heat of solution increases with an increase of the percentage loading of the OV-101 up to 10%. Solution and adsorption thermodynamic characteristics of the studied system are briefly discussed.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Metal complexes ; Chemically bonded phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Packings consisting of diphenylphosphine complexes with CoCl2 and CoBr2, chemically bonded to the silica surface, were synthesized and their retention parameters determined. The packings are capable of specifically interacting with electron-donating compounds by forming π-complexes. The interaction is considerably stronger in the case of CoBr2-containing packing than in the case of CoCl2-containing packing.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 18 (1984), S. 234-238 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open-tubular columns ; On-column injection ; Stopped-flow operation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple, inexpensive, on-column injector of the septum moving-needle kind is described for quantitative analysis using open-tubular columsn. when operated in the stopped-flow mode an improvement incolumn efficiency is observed combined wit a diminished tendency to produce split-top peaks, particularly for late eluting peaks. Using electronic integration a relative error of about 2.7% was observed for peaks spanning a wide range of sample concentrations and volatilities.
    Type of Medium: Electronic Resource
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 18 (1984), S. 243-248 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Carrier gas ; Viscosity ; Influence of temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The vicosity-temperature relationship of the three gases (helium, nitrogen and hydrogen) most frequenly used as the carrier gas in gas chromatography is studied. Based on available data, equaitions are derived to describe this relationship. Using these equations viscosity data are tabulated for the chromatographically important temperature range.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 18 (1984), S. 260-264 
    ISSN: 1612-1112
    Keywords: Parabens and their dissolution ; Pharmaceutical dosage forms ; Derivatization ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A specific, sensitive and general applicabla gas chromatographic method is described for the determination of parabens in various liquid pharmaceutical preparations: propylparaben and butylparaben in a liquid antacid dosage form (I); methylparaben, ethylparaben and propylparaben in a syrup (II); methylparaben and propylparaben in a solution for injection (III). Each time one of the parabens is used as internal standard. The parabens are extracted with diethylether and derivatized by silylation. Different columns are used for the analysis of the parabens: 3% SE-30 column, a 3% QF-1 column for different selectivity, a 2% OV-1 column for isothermal operation. Special attention is attributed to the standard: the parabens are dissolved in a minimal amount of 0.1 M sodium hydroxide and extracted in the same way as the pharmaceutical dosage form.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Configuration ; Resolution ; Alcohols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The study of the resolution of sixteen secondary aliphatic alcohols by gas chromatography on (+)-dodecyl (2R, 3R)-tartrate, trapping the ascending part of the peak from a conventional filled column, has allowed the determination in a single operation of the sign and order of emergence of enantiomers. A correlation between the configuration of these secondary alcohols and their order of emergence has been established.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 18 (1984), S. 309-312 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Carboxylic acids ; Acetonyl derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of the acetonyl esters of nine aliphatic carboxylic acids is described, the general formula of the derivatives being RCOOCH2COCH3 where R=alkyl or H. The derivatives show good chromatographic properties on both packed and capillary columns. The electron impact and chemical ionisation mass spectra of the derivatives are discussed.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Thermodynamic relationships ; Retention index ; Peak identification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A thermodynamic criterion, ΔQ, is suggested which permits to estimate the difference in the functional group energy of interactions for two different stationary phases. The linear dependence of ΔQ on the homolog number m of any series Rm X can be used as the thermodynamic criterion for the identification of substances by GC analysis.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 18 (1984), S. 477-488 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Open tubular (capillary) columns ; Sample capacity ; Column comparison ; Film thickness ; Column diameter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Wall-coated, open-tubular (capillary) columns prepared from different diameter tubing, with different liquid phase film thickness, are compared with each other and with packed and support-coated open-tubular columns. The comparison is based on the variation of the phase ratio and the capacity factor, and includes column efficiency (HETP, theoretical plate number), resolution, retention time, and sample capacity. Problems associated with the evaluation of the sample capacity are outlined. The influence of temperature on column performance is discussed in detail. Finally, the possibilities of short, wide-bore open-tubular columns prepared with a thick liquid-phase film are demonstrated.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1940-1953 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Charge-Transfer Complexes of Tetrathiafulvalene (TTF) with 1,2,5-Thiadiazolequinones1)The syntheses and the X-ray structure analyses of the charge-transfer complexes of tetrathiafulvalene (TTF) with naphtho[2,3-c][1,2,5]thiadiazole-4,9-dione (1 : 2) (2) and benzol[1,2-c: 4,5-c′]-bis[1,2,5]thiadiazole-4,8-dione (1 : 1) (4) are reported. In their crystal structures both compounds are built up by mixed columnar stacks of donors and acceptors, forming a characteristic packing motive for organic D-A complexes with properties of an electrical insulator.
    Notes: Es wird über die Synthese und die Einkristallröntgenstrukturanalysen der Charge-Transfer-Komplexe von Tetrathiafulvalen mit Naphtho[2,3-c][1,2,5]thiadiazol-4,9-dion (1 : 2) (2) und Benzo-[1,2-c: 4,5-c′]bis[1,2,5]thiadiazol-4,8-dion (1 : 1) (4) berichtet. Beide Verbindungen weisen in ihrer Kristallstruktur aus Donoren und Acceptoren gemischte kolumnare Stapel auf, ein charakteristisches Packungsmotiv organischer D-A-Komplexe mit elektrischen Isolatoreigenschaften.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1973-1976 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Generation of Nitrosyl Salts in Dry Organic MediaTrimethylsilyl halides (CH3)3SiX (2a - c, X = Cl, Br, I) are sufficiently electrophilic to cleave, in an equilibrium reaction, alkyl nitrites O = NOR (1a, b, R = i-C5H11, C2H5) with formation of O = NX (3a - c) and (CH3)3SiOR (4a, b). This reaction serves as a convenient in-situ-method to generate nitrosyl compounds NOX in chlorinated hydrocarbons as inert organic media.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1954-1964 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Iminoboranes from the Thermal Decomposition of DialkylazidoboranesIminoboranes RB = NR (1a - f) are formed by the thermal decomposition of azidoboranes R2BN3 (5a - f) in the gas phase or in solution. At low temperature, the iminoboranes 1b, d, e (R = iPr, iBu, sBu) can be trapped from the gas phase. They are characterized and brought to reaction as isolated species. Without other reactands, the iminoboranes dimerize or trimerize to form the cyclic products 2 or 3, respectively, or polymerize to the wax-like solids 4. Produced in solution below 100 °C, the iminoboranes are azidoborated by the educts 5 to give the (azidoboryl)amines 6 which are transformed into the borazines 3 at 160 - 180 °C. Iminoboranes undergo an ethyloboration with BEt3, a cycloaddition with PhN3, and in the absence of the strongly reactive R2BN3 a concurring cycloaddition and azidosilation with Me3SiN3 with formation of 7 - 10, respectively.
    Notes: Iminoborane RB = NR (1a - f) entstehen beim thermischen Zerfall von Azidoboranen R2BN3 (5a - f) in der Gasphase oder in Lösung. Die aus der Gasphase abgeschiedenen Produkte 1b, d, e (R = iPr, iBu, sBu) lassen sich bei tiefer Temperatur isolieren, charakterisieren und isoliert umsetzen. Mit sich selbst reagieren die in der Gasphase ergzeugten Iminoborane 1a - f unter Cyclodi-oder -trimerisierung oder unter Polymerisierung zu Produkten von Typ 2, 3 bzw. 4. In Lösung unterhalb 100 °C erzeugt, werden die Iminoborane von den Edukten 5 zu Produkten 6 azidoboriert; diese lassen sich bei 160 - 180 °C in Borazine 3 überführen. Iminoborane erfahren durch BEt3 eine Ethyloborierung zu 7, mit PhN3 eine Cycloaddition zu 8 und mit Me3SiN3 nebeneinander eine Cycloaddition zu 9 und eine Azidosilierung zu 10, sofern nicht das Edukt R2BN3 zugegen ist, das dem Azid Me3SiN3 in der Reaktivität gegenüber 1 überlegen ist.
    Additional Material: 6 Tab.
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  • 20
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1965-1972 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azodesilylation - a Novel Aprotic Diazotization TechniqueNitrosyl compounds NOA (4a - e, A = Cl, Br, BF4, CF3SO3, I) - generated partially in situ from O = N - OR/(CH3)3SiA (7a, b, R = i-C5H11, C2H5/8a, b, e, A = Cl, Br, I) - react in aprotic organic media with N,N-bissilylated organylamines RN[Si(CH3)3]2 (3b, R = C6H5; 15, R = CH3) under generation of diazonium systems R - N2+ A- and formation of non-nucleophilic hexamethyldisiloxane (6b). This method represents the first nucleophile excluding diazotization technique on the basis of three-coordinated nitrogen and is termed „azodesilylation“.
    Notes: Nitrosylverbindungen NOA (4a - e, A = Cl, Br, BF4, CF3SO3, I) - teilweise in situ hergestellt aus O = N - OR/(CH3)3SiA (7a, b, R = i-C5H11, C2H5/8a, b, e, A = Cl, Br, I) - reagieren mit N,N-bissilylierten Organylaminen RN[Si(CH3)3]2 (3b, R = C6H5; 15, R = CH3) in aprotischen organischen Medien unter Bildung von Diazonium-Systemen R - N2+ A- und nicht-nucleophilem Hexamethyldisiloxan (6b). Diese Methode repräsentiert die erste, Nucleophile ausschließende Diazotierungstechnik auf der Basis von 3fach koordiniertem Stickstoff und wird als „Azodesilylierung“ bezeichnet.
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  • 21
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1977-1979 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Säurekatalysierte Cyclisierung des En-Produkts aus α-Pinen und PTADAluminiumchlorid-katalysierte Reaktion des En-Produkts 2 aus 4-Phenyl-4H-1,2,4-triazol-3,5-dion (PTAD) und α-Pinen (1), des 1-(6,6-Dimelthyl-2-methylenbicyclo[3.1.1]hept-3-yl)-4-phenyl-1,2,4-triazolidin-3,5-dions, ergab 3,8,8-Trimelthyl-N-phenyl-4,5-diazatricyclo[4.2.1.03,7]nonan-4,5-dicarboxamid (6) in 78% Ausbeute. Auch Bortrifluorid-etherat, trockener Chlorwasserstoff und p-Toluolsulfonsäure katalysieren die Cyclisierung von 2 zu 6, aber nicht in diesem Maße. Der Mechanismus der Cyclisierung wird über eine Gerüstumlagerung der Carbenium-Ionen-Zwischenstufen gedeutet.
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  • 22
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1980-1981 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chain Lengthening of Tetrafluoro-1,2-ethanedisulfenyl Dichloride by the Reaction with Hydrogen PeroxideThe reaction of the little compound ClSCF2CF2SCl (1) with aqueous H2O2 results in the formation of ClS2CF2CF2SSCF2CF2SO2Cl(2), which is characterized on the basis of 19F NMR, mass, IR, and Raman spectroscopy.
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  • 23
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1982-1986 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Fluorination of Adamantane Derivatives with Oxygen DifluorideFluorination of adamantane and adamantane derivatives 1 with OF2 in the absence of an HF-trap gives fluoroadamantanes 2 and adamantanols 3 in varying amounts. Increasing yields of 2 are obtained in the presence of Na2CO3 as an HF-trap. In addition, the fluorooxahomoadamantanes 4b and e are formed in this reaction. The fluorination of adamantanone (5) with OF2 leads to analogous products.
    Additional Material: 2 Tab.
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  • 24
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1987-1990 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photoelektronenspektren einiger Reduktionsprodukte von [2.2]ParacyclophanAnhand des He(I)-Photoelektronen(PE)-Spektrums von 2,3′,5,6′-Tetrahydro[2.2]paracyclophan (2) wird gezeigt, daß die Through-Bond-Wechselwirkung zwischen den Sechsringen klein, innerhalb der Cyclohexadienringe aber groß ist. Über die PE-Spektren der weiteren Hydrierungsprodukte 3 und 4 wird berichtet.
    Additional Material: 2 Ill.
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  • 25
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1991-1993 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with Cyclobutadienes, 51). 5,5,6,6-Tetracyano-5,6-dihydro-Dewar benzene/3,3,4,4-Tetracyano-3,4-dihydrobenzvalene - a Novel Equilibrating SystemThe cyclobutadiene 3 reacts with tetracyanoethylene to give a 1 : 1-mixture of the dihydro-Dewar benzene 5 and the dihydrobenzvalene 6, which can be separated by crystallisation. In deuteriochloroform solution 5 and 6 are in a 1 : 1 equilibrium.
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  • 26
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 27
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2275-2286 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Electron Rich Heterocycles as Donor Groups in Fluorescent DyesThe synthesis of N-methylphthalimides substituted with the donor groups pyrazole, triazole, benzotriazole, and naphthotriazole in position 4 is described (17, 18, 14, 12). The substituent constants of these groups are obtained by alkaline hydrolysis of the corresponding phthalimide dyes. Their solvatochromism in absorption and fluorescence gives information about charge distribution in ground- and excited state.
    Notes: Die Darstellung von N-Methylphtalimiden wird beschrieben, die in 4-Stellung die Donorgruppen Pyrazol, Triazol, Benzotriazol und Naphthotriazol tragen (17, 18, 14, 12). über die alkalische Hydrolyse des Imids werden die Substituentenkonstanten der Reste bestimmt. Die Solvatochromie in Absorption und Fluoreszenz gibt Information über die Ladungsverteilung in Grund- und angeregtem Zustand.
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  • 28
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, IV1). Synthesis of (6-Phosphonio-η5-cyclohexadienyl)ruthenium(II) Compounds and their Conversion into Dicationic (Benzene)ruthenium(II) Complexes[C6H6Ru(PR3)(PR3′)PR3″]2+The complexes [C6H6RuCl(PR3)PR3′]PF6 (1 - 4) and [C6H6RuCl2(PR3)] (9, 10) react with phosphanes PR3″ in the presence of NH4PF6 to give the (6-phosphonio-η5-cyclohexadienyl)ruthenium(II) compounds [(6-R3″P-η5-C6H6)Ru(PR3)(PR3′)PR3″](PF6)2 (5 - 8 11). Similarly, from [C6H6Ru(CH3CN)3](PF6)2 (12) and PMe3 the complex [(6-Me3P-η5-C6H6)Ru(PMe3)2CH3CN](PF6)2 (13) is formed. The IR and NMR spectra of 5 - 8, 11, and 13 indicate that the phosphonio group is in the exo-position at the sp3 carbon atom of the cyclohexadienyl ligand. Below - 30°C, rotation around the metal-ring bond is so hindered that rigid conformers are detected. Compounds 5 - 8 react with trifluoroacetic acid with elimination of the phosphonio group to yield the PF6 salts of the half-sandwich type complexes [C6H6Ru(PR3)(PR3′)PR3″]2+ (14 - 17).
    Notes: Die Komplexe [C6H6RuCl(PR3)PR3)]PF6 (1 - 4) und [C6H6RuCl2(PR3)] (9, 10) reagieren mit Phosphanen PR3″ in Gegenwart von NH4PF4 zu den (6-Phosphonio-η5-cyclohexadienyl)-ruthenium(II)-Verbindungen [(6-R3″P-η5-C6H6)Ru(PR3)(PR3″](PF6)2 (5 - 8, 11). Aus [C6H6Ru(CH3CN)3](PF6)2 (12) und PMe3 erhält man analog den Komplex (6-Me3P-η5-C6H6)Ru(PMe3)2CH3CN](PF6)2 (13). Die IR- und NMR-Spektren von 5 - 8, 11 und 13 weisen darauf hin, daß sich die Phosphoniogruppierung in der exo-Position am sp3-C-Atom des Cyclohexadienylliganden befindet. Unterhalb - 30°C ist die Rotation um die Metall-Ring-Bindung so stark behindert, daß starre Konformere nachweisbar sind. Die Verbindungen 5 - 8 reagieren mit Trifluoressigsäure unter Abspaltung der Phosphoniogruppe zu den PF6-Salzen der Halbsandwich-Komplexe [C6H6Ru(PR3)(PR3′)PR3″]2+ (14 - 17).
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  • 29
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, VI1). Synthesis of [(RC6H5)OsI(PMe3)2]PF6 from (exo-6-RC6H6)OsI(PMe3)2: A contribution to the Mechanism of Aromatization of Substituted Cyclohexadienyl Ligands by „endo-H Abstraction“The compounds (exo-6-RC6H6)OsI(PMe3)2 (2 - 5, 7) react smoothly with [CPh3]PF6 in acetone to give the (arene)osmium(II) complexes [(RC6H5)OsI(PMe3)2]PF6 (8 - 12) in quantitative yield. The hydride elimination proceeds via two (cyclohexadienyl)hydridoosmium(IV) intermediates (13 and 14, 15, respectively) which can be prepared from 2, 5, 6 (R = CH3, n-C4H9, t-C4H9) and CF3CO2H/NH4PF6. The (cyclohexadienyl)hydrido complexes [(RC6H6)Os(H)I(PMe3)2]+ undergo an intramolecular isomerization which leads to a cation possessing a CH2 group in the six-membered ring. This cationic complex or (more probably) the neutral compound (2- or 3-RC6H6)OsI(PMe3)2 formed on deprotonation reacts with [CPh3]+ by abstraction of an exo-hydrogen atom.
    Notes: Die Verbindungen (exo-6-RC6H6)OsI(PMe3)2 (2 - 5, 7) reagieren mit [CPh3]PF6 in Aceton rasch und quantitativ zu den (Aromaten)osmium(II)-Komplexen [(RC6H5)OsI(PMe3)2]PF6 (8 - 12). Die Hydrid-Eliminierung verläuft über zwei (Cyclohexadienyl)hydridoosmium(IV)-Zwischenstufen (13 bzw. 14, 15), die aus 2, 5, 6 (R = CH3, n-C4H9, t-C4H9) und CF3CO2H/NH4PF6 synthetisiert werden können. Die (Cyclohexadienyl)hydrido-Komplexe [(RC6H6)Os(H)I(PMe3)2]+ gehen eine intramolekulare Isomerisierung ein, wobei ein Kation mit einer CH2-Gruppe im Sechsring entsteht. Dieses Komplexkation oder (wahrscheinlicher) die nach Deprotonierung erhaltene Neutralverbindung (2- bzw. 3-RC6H6)OsI(PMe3)2 reagiert mit [CPh3]+ unter Abstraktion eines exo-H-Atoms.
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  • 30
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arene(phosphane)metal Complexes, V1). On the Addition of Carbanions to (Benzene)ruthenium(II) and -osmium(II) Complexes. The Crystal and Molecular Structure of (exo-6-n-C4H9-η5-C6H6)OsI(PMe3)2The complex [C6H6RuCl(PMe3)2]PF6 (1) reacts with methyllithium to give a mixture of products that contains (η5-C6H6CH3)RuCH3(PMe3)2 (2) as the main component. From 1 and LiC6H5/LiBr the bromide 3 is primarily formed but the final product is (η5-C6H6C6)H5RuC6H5(PMe3)2 (4). Reaction of [C6H6OsI(PMe3)2]PF6 (5) with organyllithium compounds LiR (R = CH3, C2H5, n-C3H7, n-C4H9, t-C4H9, C6H5) yields the complexes (η5-C6H6R)OsI(PMe3)2 (6 - 11). 31P NMR spectra of 6 - 11 indicate restricted rotation at low temperatures around the metal-ring axis. According to X-ray structure analysis of 9 (R = n-C4H9) the cyclohexadienyl ring possesses an envelope conformation. The n-butyl group occupies the exo-position at the sp3-C atom.
    Notes: Der Komplex [C6H6RuCl(PMe3)2]PF6 (1) reagiert mit Methyllithium zu einem Produktgemisch, welches (η5-C6H6CH3)RuCH3(PMe3)2 (2) als Hauptkomponente enthält. Aus 1 und LiC6H5/LiBr entsteht über 3 bei längeren Reaktionszeiten (η5-C6H6C6H5)RuC6H5(PMe3)2 (4). Die Umsetzung von [C6H6OsI(PMe3)2]PF6 (5) mit Organyllithium-Verbindungen LiR (R = CH3, C2H5, n-C3H7, n-C4H9, t-C4H9, C6H5 ergibt die Komplexe (η5-C6H6R)OsI(PMe3)2 (6 - 11), in denen nach den 31P-NMR-Spektren die Rotation um die Metall-Ring-Bindung bei tiefen Temperaturen stark eingeschränkt ist. Die Röntgenstrukturanalyse von 9 (R = n-C4H9) beweist die „Envelope“-Konformation des Cyclohexadienylrings. Die n-Butylgruppe befindet sich in der exo-Position am sp3-C-Atom.
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  • 31
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 172-186 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radical Ions, 55. The One-Electron Oxidation of Tetrahedrane to Cyclobutadiene Radical CationTetra-tert-butyltetrahedrane, on one-electron oxidation using AlCl3 in CH2Cl2, opens to form tetra-tert-butylcyclobutadiene radical cation, which can also be generated under identical reaction conditions from tetra-tert-butylcyclobutadiene itself. The assignments of the ESR and ENDOR spectra are supported by deutero substitution of one tert-butyl group and by MNDO hypersurfaces for the thermal and for the oxidative structural changes of both C4 skeletons. The feasible formation of a valence isomeric tert-butyl(tri-tert-butylcyclopropenyl)carbene radical cation is discussed.
    Notes: Tetra-tert-butyltetrahedran öffnet sich bei Einelektronen-Oxidation mit AlCl3 in CH2Cl2 zum Tetra-tert-butylcyclobutadien-Radikalkation, das unter gleichen Reaktionsbedingungen auch aus Tetra-tert-butylcyclobutadien erzeugt werden kann. Die Zuordnungen der ESR- und ENDOR-Spektren werden durch Deutero-Substitution einer tert-Butyl-Gruppe sowie durch MNDO-Hyperflächen für die thermischen und oxidativen Strukturänderungen der beiden C4-Gerüste gestützt. Die mögliche Bildung eines valenzisomeren tert-Butyl(tri-tert-butylcyclopropenyl)carben-Radikalkations wird diskutiert.
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  • 32
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 948-954 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Acidic Complexones Bearing Donor-enhancing Pyridine Anchour GroupsThe synthesis, complex stability and -selectivity for alkaline earth metal ions of 2,6-pyridinebis-(methylamine)-N, N, N′, N′-tetraacetic acid (3a) and of their donor-enforced analogues 3b, c are described. The acid dissociation constants and the stability constants of the metal complexes have been measured potentiometrically at 25°C in water of constants ionic strength (μ = 0.1). The stability order is Ca 〉 Mg 〉 Sr 〉 Ba which is analogues to the selectivity of EDTA and comparable aliphatic complexones. The magnitudes of the stability constants of 3a are comparable to those of EDTA, while the donor-enforced analogues 3b, c form less stable complexes with alkaline earth metal ions.
    Notes: Synthese, Komplexstabilität und -selektivität gegenüber Erdalkalimetall-Ionen von 2,6-Pyridinbis(methylamin)-N, N, N′, N′-tetraessigsäure (3a) und ihren Donor-verstäkten Analoga 3b, c werden beschrieben. Die Bestimmung der Dissoziations- und Komplexbildungskonstanten erfolgt potentionmetrisch bei 25°C in Wasser konstanter ionaler Stärke (μ = 0.1). Die Bildungskonstanten der Metallkomplexe nehmen in der Reihenfolge Ca 〉 Mg 〉 Sr 〉 Ba ab und folgen damit der bei EDTA und vergleichbaren aliphatischen Komplexonen vorgefundenen Selektivität. 3a weist mit EDTA vergleichbare hohe Komplexbildungskonstanten auf, während die Donor-verstärkten Analoga 3b, c schwächere Erdalkalimetallkomplexe bilden.
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  • 33
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 959-965 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Preparation and X-Ray Structure Analysis of the Diels-Alder Adduct of 4-Phenyl-4H-1,2,4-triazole-3,5-dione with OctavaleneIn the reaction of 4-phenyl-4H-1,2,4-triazole-3,5-dione with octavalene (1) the Diels-Alder adduct 2 is formed. From its X-ray structure analysis the dihedral angle for the bicyclo[1.1.0]butane group, the 2- and 4-positions of which are spanned by four atoms, has been determined to be 122.7°. The bridging bond C1 - C3 has a length of 1.487 Å.
    Notes: Aus Octavalen (1) und 4-Phenyl-4H-1,2,4-triazol-3,5-dion bildet sich das Diels-Alder-Addukt 2. Seine Röntgenstrukturanalyse ergab für das Bicyclo[1.1.0]butan-Gerüst, dessen 2- und 4-Stellung durch vier Atome überbrückt sind, einen Interplanarwinkel von 122.7°. Die Brückenbindung C1 - C3 hat eine Länge von 1.487 Å.
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  • 34
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Condensed Ring Systems, XV. About the Reaction of α-Chloro Sulfoxides with Potassium tert-Butoxide by the Example of the Synthesis of OxapropellenesThe synthesis of dithia- 1a - 3a and oxathiapropellenes 1b - 3b is described. From 1b - 3b the α-chloro sulfoxides 4 - 6 and α-chloro sulfones 4a - 6a are prepared, or which in most cases several stereoisomeric racemates are obtained. The constitution, configuration, and conformation of the α-chloro sulfoxide 4, the main product obtained from 1b, was elucidated by X-ray structure analysis. Only in that way it was possible to deduce the constitutions and configurations of the other stereoisomeric α-chloro sulfoxides 4 - 6 and α-chloro sulfones 4a - 6a, respectively, using 13C NMR spectroscopy. By the reaction of the α-chloro sulfones 4a - 6a with potassium tert-butoxide (Ramberg-Bäcklund reaction) the corresponding oxapropellenes 7 - 9 are obtained only in low yields (〈 10%). Contrary, the α-chloro sulfoxides 4 - 6, und analogous conditions give yields of 80 - 90% (from 4, 6) and 25% (from 5).
    Notes: Es wird die Synthese der Dithia- 1a - 3a und Oxathiapropellene 1b - 3b beschrieben. Aus 1b - 3b werden die α-Chlorsulfoxide 4 - 6 und α-Chlorsulfone 4a - 6a hergestellt, von denen meist mehrere stereoisomere Racemate erhalten werden. Konstitution, Konfiguration und Konformation des Hauptprodukts der aus 1b erhaltenen α-Chlorsulfoxide 4 wurden durch Röntgenstrukturanalyse ermittelt. Erst dadurch wurde es möglich, mit Hilfe der 13C-NMR-Spektroskopie die Konstitutionen und Konfigurationen der anderen stereoisomeren α-Chlorsulfoxide 4 - 6 und α-Chlorsulfone 4a - 6a aufzuklären. Bei der Reaktion der α-Chlorsulfone 4a - 6a mit Kalium-tert-butylat (Ramberg-Bäcklund-Reaktion) erhält man die entsprechenden Oxapropellene 7 - 9 nur in geringer Ausbeute (〈 10%), während die α-Chlorsulfoxide 4 - 6 unter analogen Bedingungen Ausbeuten von 80 - 90% (aus 4, 6) und 25% (aus 5) ergeben.
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  • 35
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 982-989 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Selectivity of the Reaction of Carbocations with NucleophilesThe problem of the selectivity of the nucleophilic attack on carbocations according to the HSAB-principle is discussed in relation to the solvolysis in ether of 7,7-bis(trifluoromethylsulfonyloxy)-norbornane (2) and 7,7-bis(trifluoromethylsulfonyloxy)-2-norbornene (4) in presence of dimethyl-magnesium, magnesium iodide and methylmagnesium iodide. The nucleophiles and carbocations are arranged according to the hard-soft-scale, so our results can be explained.
    Notes: Das Problem der Selektivität beim nucleophilen Angriff an Carbokationen wird im Rahmen des HSAB-Prinzips am Beispiel der Solvolysen in Ether von 7,7-Bis(trifluormethylsulfonyloxy)norbornan (2) und 7,7-Bis(trifluormethylsulfonyloxy)-2-norbornen (4) in Anwesenheit von Dimethylmagnesium, Magnesiumiodid und Methylmagnesiumiodid erörtert. Die Nucleophile und die als Zwischenstufen auftretenden Carbokationen werden auf der Hart-weich-Skala eingeordnet, wobei die Ergebnisse erklärt werden können.
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  • 36
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1003-1012 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dichloropalladium(II) Complexes with α-Amino Acids, α-Amino Acid Esters, Dipeptides, and Dipeptide EstersA series of trans-dichloropalladium(II) complexes Cl2PdL2 (L = α-amino acid, α-amino acid ester, dipeptide, dipeptide esters) and cis-Cl2Pd(histidine) has been prepared and spectroscopically characterized. The X-ray structure of trans-Cl2Pd(GlyOEt)2 (3b) has been determined.
    Notes: Eine Reihe von trans-Dichloropalladium(II)-Komplexen Cl2PdL2 mit (L = α-Aminosäure, α-Aminosäureester, Dipeptid, Dipeptidester) sowie cis-Cl2Pd(Histidin) wurde dargestellt und spektroskopisch charakterisiert. Die Röntgenstruktur von trans-Cl2Pd(GlyOEt)2 (3b) wurde bestimmt.
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  • 37
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1436-1454 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Evidence for a Radical Chain Mechanism for the Knabe Reaction of 1,2-Dihydro-2-methylpapaverineA free radical chain mechanism is proposed for the Knabe reaction and the accompanying elimination reaction on account of their nonintegral reaction order and of successful inhibition experiments. 3,4-Dimethoxybenzyl radicals are the chain carrying species. Battersby's synthesis of N-methylpavine (19) from 1,2-dihydro-2-methylpapaverine (9) is dependent on the presence of formic acid as radical chain inhibitor. In the presence of inhibitors 1-benzyl-1,4-dihydro-2-methyl-isoquinolinium ions like 10 are persistent species whose chemistry can now be investigated.
    Notes: Die Knabe-Reaktion von 1,2-Dihydro-2-methylpapaverin (9) und die begleitende Eliminierungsreaktion wurden durch ihre gebrochene Reaktionsordnung und durch die Möglichkeit der Inhibition als Radikalkettenreaktionen erkannt, deren kettentragendes Radikal das 3,4-Dimethoxybenzylradikal ist. Die Synthese von N-Methylpavin (19) aus 1,2-Dihydro-2-methylpapaverin (9) ist an die Anwesenheit von Ameisensäure als Inhibitor der Radikalketten gebunden. Durch Zusatz von Inhibitoren können nun Immoniumionen 10 und analoge Verbindungen stabilisiert und ihre Chemie untersucht werden.
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  • 38
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1455-1464 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azo Bridges from Azines, III. Unexpected Formation of a Compounds with Parallel C=C and N=N Bonds2)Dialdehyde 5 reacts with hydrazine at pH 〉 7 to form the trimeric azine 6Tr, at pH 〈 4, however, to yield unexpectedly 8, which contains parallel C=C and N=N bonds in close proximity. The complex reaction is clarified. 8 is characterized by structure proving reactions and its spectroscopic data.
    Notes: Der Dialdehyd 5 reagiert mit Hydrazin bei pH 〉 7 zu dem trimeren Azin 6Tr, bei pH 〈 4 unerwartet zu 8, das parallel benachbarte C=C- und N=N-Bindungen besitzt. Der komplexe Reaktionsverlauf wird aufgeklärt. 8 wird durch struktursichernde Reaktionen und spektroskopische Daten charakterisiert.
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  • 39
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1465-1475 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azo Bridges from Azines, IV1). Intramolecular [2 + 2] Photocycloaddition of Parallel C=C and N=N BondsThe parallel C=C and N=N bonds in the rigid molecules 1 - 10 photocyclize nearly quantitatively, forming 1,2-diazetidines 11 - 20. Their structure is confirmed by spectroscopic methods and for 13 by X-ray analysis. Radiation induced denitrogenation, the normal reaction for similar compounds without neighbouring C=C bonds, is suppressed even with the sensitive derivatives of 2,3-diazabicyclo[2.2.1]heptene. Photocyclization of 6, carrying two neighbouring C=C bonds, includes only the norbornene bond.
    Notes: In den starren Molekülen 1 - 10 reagieren die benachbarten parallelen C=C- und N=N-Bindungen nahezu quantitativ unter Photocyclisierung zu den 1,2-Diazetidinen 11 - 20, deren Struktur spektroskopisch und für 13 durch Kristallstrukturanalyse bewiesen wird. Die in Abwesenheit der C=C-Bindung beobachtete Photo-Denitrogenierung unterbleibt selbst bei den empfindlichen Derivaten des 2,3-Diazabicyclo[2.2.1]heptens. Photocyclisierung von 6 mit zwei zur N=N-Bindung benachbarten C=C-Bindungen tritt nur mit der Norbornendoppelbindung ein.
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  • 40
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1497-1512 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids, 21,2). N-Acetyl α,β-Didehydro α-Amino Acid Esters from α-Azidocarboxylic Acid Esters and Acetic Anhydride by Nitrogen Elimination with Rhenium Catalystsα-Azidocarboxylic acid esters 2 react with acetic anhydride in presence of catalytic amounts of rhenium heptasulfide and - if necessary - by addition of hydrochloric acid to give N-acetyl 3 or/and N,N-diacetyl-α,β-didehydro-α-amino acids esters 4 in very good yields. Exclusively monoacetylated products 3 are formed if water ist added before work up.
    Notes: Beim Erwärmen von α-Azidocarbonsäureestern 2 in Acetanhydrid/Essigsäure in Gegenwart katalytischer Mengen Rheniumheptasulfid und gegebenenfalls unter Zugabe von Chlorwasserstoff entstehen in sehr guten Ausbeuten N-Acetyl- 3 und/oder N,N-Diacetyl-α-β-didehydro-α-amino-säureester 4. Durch Zugabe von Wasser vor der Aufarbeitung erfolgt partielle Deacetylierung unter ausschließlicher Bildung der N-Monoacetylverbindungen 3.
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  • 41
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amino Acids, 31). N-Acetylated α-β-Didehydro α-Amino Acid Derivatives by Nitrogen Elimination from α-Azido-carboxylic Acid Amides and α-Azido-ω-aminocarboxylic Acid Lactams with Rhenium Catalystsα-Azidocarboxylic acid amides 2 and α-azido-ω-aminocarboxylic acid lactams 6, respectively, react with acetic anhydride in the presence of rhenium catalysts by nitrogen eliminations to give N-acetyl- 7 and N,N-diacetyl-α,β-didehydro-α-amino acid amides 8, α-acetylamino- 11 and α-diacetylamino-α,β-didehydro-ω-aminocarboxylic acid lactams 12, respectively. Reactions of the educts 6c, d - with a ring size 7 or 8 - additionally lead to the oxazoloazepine 14c and the oxazoloazocine 14d, respectively.
    Notes: Bei der Umsetzung von α-Azidocarbonsäureamiden 2 mit Acetanhydrid in Gegenwart von Rheniumkatalysatoren entstehen unter Stickstoffabspaltung N-Acetyl- 7 und N,N-Diacetyl-α,β-didehydro-α-aminosäureamide 8, bei der von α-Azido-ω-aminocarbonsäurelactamen 6 α-Acetyl-amino- 11 und α-Diacetylamino-α,β-didehydro-ω-aminocarbonsäurelactamen 12, wobei sich aus den Verbindungen 6c, d, mit der Ringgliederzahl 7 bzw. 8 außerdem noch das Oxazoloazepin 14c bzw. das Oxazoloazocin 14d bilden.
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  • 42
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus, 131. Synthesis and Properties of the Methylenediphosphiranes (t-BuP)2)C = CR2 (R = H, Me, 4-ClC6H4)The first methylenediphosphiranes (diphosphamethylenecyclopropanes) (t-BuP)2C = CH2 (1), (t-BuP)2C = CMe2 (2), and (t-BuP)2C = C(4-ClC6H4)2 (3) were synthesized by [2 + 1] cyclocondensation of K(t-Bu)P - P(t-Bu)K with the corresponding 1,1-dichloroolefins. The homocyclophosphanes (t-BuP)n (n = 4,3) and in the case of 1 mainly H(t-Bu)P - P(t-Bu)H are formed as by-products. The three-membered heterocycles 2 and 3 could be purely isolated as surprisingly stable compounds. According to an X-ray single-crystal analysis 3 possesses approximately C2 symmetry and exhibits one of the smallest bonding angles ψ (P - P - C) = 52.4° on a phosphorus atom experimentally proved so far. Along [100] there are canals filled with disordered n-pentane molecules.
    Notes: Die ersten Methylendiphosphirane (Diphosphamethylencyclopropane) (t-BuP)2C = CH2 (1), (t-BuP)2C = CMe2 (2) und (t-BuP)2C = C(4-ClC6H4)2 (3) wurden durch [2 + 1]-Cyclokondensation von K(t-Bu)P - P(t-Bu)K mit den entsprechenden 1,1-Dichlorolefinen synthetisiert. Als Nebenprodukte entstehen die Homocyclophosphane (t-BuP)n (n = 4,3) und im Fall von 1 vor allem H(t-Bu)P - P(t-Bu)H. Die Dreiringheterocyclen 2 und 3 konnten als thermisch überraschend beständige Verbindungen in reiner Form isoliert werden. 3 besitzt nach der Röntgenstrukturanalyse annähernd die Symmetrie C2 und enthält mit ψ (P - P - C) = 52.4° einen der kleinsten experimentell gesicherten Bindungswinkel am Phosphor. Längs [100] liegen fehlgeordnet mit n-Pentan gefüllte Kanäle vor.
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  • 43
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1523-1541 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminierung, III. Trimethylsilanol als austretende Gruppe, V. Silylierung-Aminierung von Hydroxy-N-heterocyclenDurch Silylierung-Aminierung lassen sich Hydroxy-N-heterocyclen (z. B. 18, 21, 26 u. a.) bequem in einer Einstufen-Eintopfreaktion aminieren (→ 20, 23 - 25 etc.). Aromatische Hydroxy-N-heterocyclen werden durch Silylierung in aktivierte und lipophile Zwischenprodukte vom Typ 3, 8 umgewandelt, die sich in situ mit Ammoniak, primären oder sekundären Aminen zu den entsprechenden mono-, bis- und tris-aminierten Produkten (5, 10) umsetzen. Die Additions-Eliminierungsreaktion von Aminen an O-silylierte Heterocyclen ist Lewissäure-katalysiert und verläuft gewöhnlich in hohen Ausbeuten, falls die austretende Gruppe Trimethylsilanol in situ durch überschüssiges Silylierungsmittel in Hexamethyldisiloxan umgewandelt wird. Anwendungsbreite und Grenzen dieser einfachen Methode werden diskutiert.
    Notes: Hydroxy N-heterocycles such as 18, 21, 26, and others are efficiently aminated in a one-step/one-pot procedure by silylation-amination to give 20, 23 - 25 etc. Silylation converts aromatic hydroxy N-heterocycles into activated and lipophilic intermediates of type 3, 8 which react in situ with ammonia, primary or secondary amines to form the corresponding mono-, bis- or tris-aminated products (5, 10). This addition-elimination of amines to O-silylated heterocycles in Lewis acid-catalyzed and proceeds usually in high yields if the leaving group trimethylsilanol is converted in situ by excess silylated agent into hexamethyldisiloxane. Scope and limitations of this simple procedure are discussed.
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  • 44
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1572-1582 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Benzonitrile as a 6-Electron Donor Ligand: The Clusters Fe3(CO)9(μ3(η2)-NCC6H5) and Fe4(CO)12(μ4(η2)-NCC6H5)The reaction of Fe3(CO)12 with benzonitrile in the presence of hydrogen leads to the benzonitrile complexes Fe3(CO)9(μ3(η2)-NCC6H5) (1a) and Fe4(CO)12(μ4(η2)-NCC6H5) (2). Their structures were determined crystallographically. The benzonitrile ligand is coordinated to the iron atoms formally via on „s̰-bond“ and two „π-bonds“ in 1a, and via three s̰-bonds and one π-bond in 2.
    Notes: Die Reaktion von Fe3(CO)12 mit Benzonitril in Anwesenheit von Wasserstoff führt zu den beiden Benzonitril-Komplexen Fe3(CO)9(μ3(μ2)-NCC6H5) (1a) und Fe4(CO)12(μ4(η2)-NCC6H5) (2). Ihre Strukturen wurden kristallographisch aufgeklärt. Der Benzonitril-Ligand ist in 1a formal über eine „s̰-Bindung“ und zwei „π-Bindungen“, in 2 über drei s̰-Bindungen und eine π-Bindung an die Eisenatome koordiniert.
    Additional Material: 2 Ill.
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  • 45
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Spin-Spin Coupling Constants by Platinium-195 as Criteria for a Configuration Determination in Platinum Organic CompoundsThe platinum organic compounds [Pt(η4-1,5-cyclooctadiene)(XC6H4)2] and cis-[Pt(P(n-Bu)3)2-(XC6H4)2] (X = H, 4-CH3, 4-(CH3)3C, 4-(CH3)2N, 3-F, 4-F, 4-CH3O, 4-CF3; 3a - 4, cis-4a - h) as well as trans-[Pt(P(n-Bu)3)2(4-CH3OC6H4)2] (trans-4g) and trans-[Pt(P(n-Bu)3)2(4-CF3C6H4)2] (trans-4h) have been studied by 31P-, 13C-, and 1H NMR spectroscopy. The coupling constants 1J[195Pt, 31P], nJ[195Pt, 13C], nJ[195Pt, H], and 2J[31P, 13C] show a clear correlation to the ligand configuration at the dsp2-hybridized platinum and can therefore be used as basis for configuration determination.
    Notes: Die platin-organischen Verbindungen [Pt(η4-1,5-cyclooctadien)(XC6H4)2] und cis-[Pt(P(n-Bu)3)2-(XC6H4)] (X = H, 4-CH3, 4-(CH3)3C, 4-(CH3)2N, 3-F, 4-F, 4-CH3O, 4-CF3; 3a - h, cis-4a - h) sowie trans-[Pt(P(n-Bu)3)2(4-CH3OC6H4)2] (trans-4g) und trans-[Pt(P(n-Bu)3)2(4-CF3C6H4)2] (trans-4h) wurden 31P-, 13C- und 1-NMR-spektroskopisch untersucht. Die Kopplungskonstanten 1J[195Pt, 31P], nJ[195Pt, 13C], nJ[195Pt, H] und 2J[31P, 13C] zeigen eine eindeutige Abhängigkeit von der Konfiguration der Liganden am dsp2-hybridisierten Platin; sie können daher zur sicheren Konfigurations-Bestimmung verwendet werden.
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  • 46
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1597-1605 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Structure of N-Methylenecarboxamides: X-Ray Data, Spectroscopy, and Quantum Mechanical CalculationsN-(Diphenylmethylene)acetamide (1) has been studied by X-ray crystallography as an example for the polyfunctional, highly reactive N-methyleneamides. The dihedral angle (C = N - C = O = 73°) and the bond lengths indicate that there is only little interaction between the C = O and the C = N groups. Extensive ab initio 3-21G calculations for the parent molecule H2C = N - CH = O (2) predict a C - N rotational barrier of ca. 4 kcal/mol with a cisoid form (C = N - C = O = 23°) as the most stable structure. MNDO data as well as spectroscopic properties (IR, 13C NMR) suggest high molecular flexibility due to the many electronic interactions possible for the nitrogen atom.
    Notes: Als Beispiel für die polyfunktionellen N-Methylencarbonsäureamide wurde N-(Diphenylmethylen)acetamid (1) röntgenographisch untersucht. C = N - C = O-Torsionswinkel (73°) und Bindungslängen deuten auf nur geringe Wechselwirkungen zwischen C = O- und C = N-Molekülteil. Ausführliche ab initio-3-21G-Berechnungen am Grundsystem H2C = N - CH = O (2) sagen eine C - N-Rotationsbarriere von ca. 4 kcal/mol voraus, wobei als stabilste Struktur eine cisoide Form (C = N - C = O-Winkel = 23°) gefunden wurde. MNDO-Daten und spektroskopische Untersuchungen (IR, 13C-NMR) deuten ebenfalls auf hohe molekulare Beweglichkeit, die vor allem durch die vielfältigen elektronischen Wechselwirkungsmöglichkeiten des Stickstoffatoms verursacht wird.
    Additional Material: 3 Ill.
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  • 47
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1659-1670 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reduction of β-Lactams, I. Reduction of 3,3,3′,3′-Tetramethyl[1,1′-biazetidine]-2,2′-dione with Complex HydridesReduction of the title compound 7 with lithium aluminium hydride leads to four products 8 to 11 in yields depending on the reaction conditions. Compounds 8 to 10 are also obtained from the bicyclic hydrazide 12, isomeric with 7. Therefore, the reduction of 7 and 12 is likely to proceed in part via common intermediates. A reaction scheme is proposed to account for the generation of the products. With other hydride reagents complex reaction mixtures are obtained from 7. The reduction of 7 to 3,3,3′,3′-tetramethyl-1,1′-biazetidine (13) failed.
    Notes: Die Reduktion der Titelverbindung 7 mit Lithiumaluminiumhydrid liefert die vier Produkte 8 - 11 in von den Reaktionsbedingungen abhängigen Mengenverhältnissen. Da die Verbindungen 8 - 10 auch aus dem mit 7 isomeren bicyclischen Hydrazid 12 erhalten werden, muß die Reduktion von 7 und 12 z. T. einheitlich ablaufen. Hierfür wird ein Reaktionsschema vorgeschlagen. Mit anderen Hydridübertragungsreagenizen entstehen aus 7 komplexe Produktgemische. Die Reduktion von 7 zu 3,3,3′,3′-Tetramethyl-1,1′-biazetidin (13) gelang nicht.
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  • 48
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 565-574 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (Trimethylstannyl)adamantane DerivativesReaction of brominated adamantane compounds with (trimethylstannyl)lithium afforded a series of (trimethylstannyl)adamantane derivatives. Additionally, we found products from fragmentation and reduction reactions which allowed conclusions concerning the mechanisms. Surprisingly high stereoselectivities were observed in most instances. By Wurtz synthesis we obtained 2-adamantyltriphenylstannane.
    Notes: Die Umsetzung bromierter Adamantanverbindungen mit (Trimethylstannyl)lithium lieferte eine Reihe von (Trimethylstannyl)adamantan-Derivaten. Wir fanden zusätzlich Fragmentierungs- und Reduktionsprodukte, die Rückschlüsse auf den Mechanismus zuließen. Überraschend ist die hohe Stereoselektivität der meisten Reaktionen. Durch Wurtz-Synthese wurde auch 2-Adamantyltriphenylstannan erhalten.
    Additional Material: 1 Ill.
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  • 49
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 575-584 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Influence of Substituents on the Valence-tautomeric Equilibrium of 4,8-Substituted HomotropilidenesThe valence-tautomeric equilibrium of 4,8-substituted homotropilidenes 2 - 4 is governed by electronic (preference of a substituent for attachment to a cyclopropyl or an aliphatic carbon atom) and steric factors. The conformational change chair → boat, which precedes the Cope rearrangement of a homotropilidene, cannot take place when both endo-8- and cis-4-substituents are present.
    Notes: Das Valenzgleichgewicht 4,8-substituierter Homotropilidene 2 - 4 wird durch elektronische (Präferenz eines Substituenten für Cyclopropyl- oder aliphatische Verknüpfung) und sterische Faktoren bestimmt. Die der Cope-Umlagerung vorgeschaltete Konformationsänderung Sessel → Boot wird verhindert, wenn das Homotropiliden sowohl in endo-8- wie in cis-4-Stellung substituiert ist.
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  • 50
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocyclic β-Enamino Esters, 311). Novel 6:7-, 6:8, and 5:6:7-Combinations of Heterocondensed Pyrimidines from Iminophosphoranes of Heterocyclic β-Enamino Esters. - Stable Heterocyclic YlidesWith acetylenic esters the (5-azolylimino)triphenylphosphoranes 10a - d do not show any cyclo-addition tendency, while the (2-thienylimino)triphenylphosphoranes 8a, b yield the stable ylids 13a, b. By treatment with phenyl isocyanate the iminophosphoranes 16a - m, 17, and 18a, b afford the carbodiimides 19a - m, 20, and 21a, b; however, 10b - d give the O-ethylisoureas 24b - d. 19a, b, e, f, h are transformed in aqueous ethanol into 6:7-bicycles, namely into oxepino[2,3-d]pyrimidines 25a, b, e, f, h. With isopropylamine the 2-isopropylamino-6:7-bicycles 31a - c, e - h are formed analogously, while in the case of thiocin 21a the 6:8-bicycle 34 is obtained. The salts 33f, g are formed by treating 19f, g or 25f with aqueous diethylamine. Accordingly, 2-aminoethanol, 3-aminopropanol, and ethylenediamine react with 19a, b, f, l to afford the 2-hydroxy- and 2-aminoalkyl-6:7-bicycles 36a - f; by treatment with hydrazine the 2-hydrazinooxepino- and -thiepino[2,3-d]pyrimidines 38a - h and 39 are obtained, which are converted with functional C1-units into 5:6:7-tricycles 43a - d, 45'a, b.
    Notes: Die (5-Azolylimino)triphenylphosphorane 10a - d zeigen mit Acetylendicarbonsäureestern keine Tendenz zur Cycloaddition, während die (2-Thienylimino)triphenylphosphorane 8a, b, zu den stabilen Yliden 13a, b reagieren. Mit Phenylisocyanat ergeben die Iminophosphorane 16a - m, 17 und 18a, b die Carbodiimide 19a - m, 20 und 21a, b; 10b - d liefern statt dessen die O-Ethylisoharnstoffe 24b - d. In wäßrigem Ethanol werden 19a, b, e, f, h in 6:7-Bicyclen, nämlich in die Oxepino[2,3-d]pyrimidine 25a, b, e, f, h umgewandelt. Mit Isopropylamin bilden sich die 2-Isopropylamino-6:7-Bicyclen 31a - c, e - h und im Fall des Thiocins 21a der 6:8-Bicyclus 34. Die Salze 33f, g entstehen durch Einwirkung von wäßrigem Diethylamin auf 19f, g bzw. auf 25f. 2-Aminoethanol, 3-Aminopropanol und Ethylendiamin ergeben mit 19a, b, f. l analog die 2-Hydroxy- und 2-Aminoalkyl-6:7-Bicyclen 36a - f; mit Hydrazin werden die 2-Hydrazinooxepino- und -thiepino[2,3-d]pyrimidine 38a - h und 39 erhalten, die mit funktionellen C1-Bausteinen zu den 5:6:7-Tricyclen 43a - d, 45'a, b führen.
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  • 51
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 682-693 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Addition of Aldehydes to Activated Double Bonds, XXXIV1). Addition of Aldehydes to Cyclic α-Methylene KetonesThe thiazolium salt-catalyzed addition of aldehydes to the cyclic α-methylene ketones 3, 4, 7, 8, 48, and 49 leads to γ-diketones 9 - 22, 50 - 53; some of them were converted into unsaturated ketones 23 - 28, pyrroles 29 - 34, 37 - 43, and furans 35, 36, 44 - 46. The α-methylene ketones were synthesized by retro Diels-Alder reaction of the corresponding norbornene compounds 1, 2, 5, 6, 47.
    Notes: Die Thiazoliumsalz-katalysierte Addition von Aldehyden an die cyclischen α-Methylenketone 3, 4, 7, 8, 48 und 49 führt zu γ-Diketonen 9 - 22, 50 - 53, aus denen einige ungesättigte Ketone 23 - 28, Pyrrol- 29 - 34, 37 - 43 und Furanderivate 35, 36, 44 - 46 synthetisiert wurden. Die Darstellung der α-Methylenketone erfolgte durch Retrospaltung entsprechender Norbornenderivate 1, 2, 5, 6 und 47.
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  • 52
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 694-701 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diazadiene als Steuerliganden in der Katalyse, 51). Synthese chiraler Diazadiene R* - N = CR' - CR' = N - R*Die im Prinzip einfache Kondensationsreaktion von Glyoxal (als Hydrat) und 2,3-Butandion mit primären Aminen führt leider bei aliphatischen Aminen mit tertiärem bzw. sekundärem α-Kohlenstoff oftmals zu unerwünschten Additionsprodukten. Unter speziellen Synthesebedingungen können mit (R)-1-Phenylethylamin (1) und (1S,2S,3S,5R)-3-(Aminomethyl)pinan die gewünschten Diimine (Diazadiene (dad): R* - N = CR' - CR' = N - R*, R' = H, CH3) 4, 6 - 8 erhalten werden. Aus (S)-2-Amino-1-butanol (3) werden je nach Dion-Komponente ein Morpholinomorpholin 9 bzw. ein Bioxazolidin 10 gebildet, die von elektronenreichen Metallen in ihrer isomeren Form als Diazadiene gebunden werden ((dad)Mo(CO)4 11 und 12). Die offenkettige dad-Form ist durch O-Silylierung (14, 15) stabilisierbar. Die (dad)Eisen(0)-katalysierte Dimerisierung von Butadien zu 4-Vinyl-1-cyclohexen mit diesen dad-Liganden ergibt Enantiomerenüberschüsse e.e. bis zu 16%.
    Notes: The condensation of glyoxal (as hydrate) or 2,3-butanedione with primary amines is, in principle, a simple reaction. Unfortunately, aliphatic amines with secondary or tertiary α-carbons often give unwanted addition products. Under special reaction conditions the desired diimines (diazadienes (dad): R* - N = CR' - CR' = N - R*, R' = H, CH3) 4, and 6 - 8 are obtained from (R-1-phenyl-ethylamine (1) and (1S,2S,3S,5R)-3-(aminomethyl)pinane (2). Depending on the dione, a morpholinomorpholine 9 and a bioxazolidine 10 are formed from (S)-2-amino-1-butanol (3), which are bound by electron-rich metals in their isomeric dad form ((dad)Mo(CO)4 11 and 12). The acyclic dad structure is stabilized by O-silylation (14, 15). The (dad)iron(0) catalyzed dimerization of butadiene with these controlling ligands to 4-vinyl-1-cyclohexene occurs with an enantiomeric excess up to 16%.
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  • 53
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Application of High-Resolution Solid State NMR Spectroscopy for the Determination of the Ring-Chain TautomerismThe structure of the benzaldehyde derivatives 1 and 2 showing ring-chain tautomerism was investigated by NMR spectroscopy in the solid state and in solution. Difficulties in preparing single crystals, low solubility, and the presence of solvent in the crystal prevent an X-ray analysis and other spectroscopic methods. The structural problem was solved by C-13 CP-MAS NMR spectroscopy. 2-[2-(Methylamino)ethyl]-3-nitrobenzaldoxime (1) exists in the chain form in the crystal but is in equilibrium with the cyclic isomer in solution. Two different types of crystals were obtained from the aminoethenylbenzaldehyde derivative 2, one of them containing the chain the other the cyclic form of 2. Signal assignments in the solid state result from comparison with the spectra in solution, which have been partially assigned by 2D 1H 13C NMR shift correlation.
    Notes: Die Struktur der Benzaldehyd-Derivate 1 und 2, die Ring-Ketten-Tautomerie zeigen, wird durch NMR-Spektroskopie im festen und gelösten Zustand untersucht. Schwierigkeiten beim Züchten von Einkristallen sowie die Schwerlöslichkeit bzw. die Anwesenheit von Kristallösungsmittel verhinderten die Anwendung der Röntgenstrukturanalyse und anderer spektroskopischer Methoden. Mit Hilfe von C-13-CP-MAS-NMR-Spektren wird das Strukturproblem lösbar. In 2-[2-(Methyl-amino)ethyl]-3-nitrobenzaldoxim (1) liegt im Kristall die offene Form vor, die in Lösung mit dem cyclischen Tautomeren 1b im Gleichgewicht steht. Vom Aminoethenylbenzaldehyd-Derivat 2 lassen sich zwei verschiedene Kristalle gewinnen, in denen alternativ die offene und die cyclische Struktur vorliegt. Zur Signalzuordnung werden die Festkörper-NMR-Spektren mit den z. T. durch 2D-1H-13C-NMR-Verschiebungskorrelation zugeordneten C-13-Spektren verglichen.
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  • 54
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 710-724 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Asymmetric Catalyses, 121). New Optically Active P,N Ligands and Their Use in Rh-Catalyzed Asymmetric Hydrogenation and HydrosilylationNew P,N-ligands 2, 4 and 5 were prepared by Schiff base condensation of (2-formylphenyl)diphenyl- and tris(2-formylphenyl)phosphane with (R)-(+)-1-phenylethylamine and ethylenediamine. (R)-(+)-aminphos (6) was obtained by hydrogenation of the C = N bond in (R)-(+)-iminphos (2). The new imine ligands form stable chelate complexes. The pseudotetrahedral CpFe(CO)[R)-(+)-iminphos]PF6 was separated into the diastereoisomes with respect to the Fe configuration. The square planar Rh[(R)-(+)-iminphos]2X is obtained as a cis/trans mixture. The isolated Rh complexes and the combinations [Rh(COD)Cl]2/2, 4, and 6, respectively, were used as catalysts for the homogeneous hydrogenation of (Z)-α-(acetylamino)cinnamic acid and for the hydrosilylation of acetophenone with diphenysilane. The optical yield of 1-phenyl-ethanol, the product of hydrolysis of the hydrosilylation, increases with increasing ligand excess, decreasing catalyst concentration, and decreasing temperature.
    Notes: Neue P,N-Liganden 2, 4 und 5 wurden durch Schiffbasenkondensation von (2-Formylphenyl)diphenyl- und Tris(2-formylphenyl)phosphan mit (R)-(+)-1-Phenylethylamin und Ethylendiamin dargestellt. (R)-(+)-aminphos (6) wurde durch Hydrierung der C = N-Bindung in (R)-(+)-iminphos (2) erhalten. Die neuen Imin-Liganden bilden stabile Chelatkomplexe. Das pseudotetraedrische CpFe(CO)[(R)-(+)-iminphos]PF6 wurde in die Diastereomeren bezüglich der Fe-Konfiguration getrennt. Das quadratisch-planare Rh[(R)-(+)-iminphos]2X fällt als cis/trans-Gemisch an. Die isolierten Rh-Komplexe und die Kombinationen [Rh(COD)Cl]2/ 2, 4 bzw. 6 wurden als Katalysatoren für die homogene Hydrierung von (Z)-α-(Acetylamino)zimtsäure und für die Hydrosilylierung von Acetophenon mit Diphenylsilan eingesetzt. Die optische Ausbeute an 1-Phenylethanol, dem Hydrolyseprodukt der Hydrosilylierung, steigt mit zunehmendem Ligandenüberschuß, mit abnehmender Katalysatorkonzentration und mit abnehmender Temperatur.
    Additional Material: 2 Ill.
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  • 55
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3021-3033 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Solvolysis of (Z)/(E)-1-Methyl-2-[2-(1-propyn-1-yl)phenyl]vinyl Triflate and 1-Methylene-2-[2-(1-propyn-1-yl)phenyl]ethyl TriflateThe synthesis and solvolysis of the triflates (Z)/(E)-8 and 20 in various solvents are described. The (E)-triflate 8 reacts in trifluoroethanol by rearrangement via the intermediate naphthyl cation 9 to give the naphthyl ether 22 and the naphthyl triflate 24. The identification of 1-bromo-2,3-dimethylnaphthalene (26) after addition of bromide ions to the solvolysis confirms 9 as a reactive intermediate. The (Z)-triflate 8 solvolyses preferably to the elimination product 28, the formation of [(3-methyl-2-naphthyl)methyl] (trifluoroethyl) ether (23), however, can not be explained via the cation 9 as an intermediate. The solvolysis of the triflate 20 leads also to the rearranged products 22 and 23.
    Notes: Die Synthese und Solvolyse der Triflate (Z)/(E)-8 und 20 in verschiedenen Lösungsmitteln wird beschrieben. Das (E)-Triflat 8 reagiert in Trifluorethanol bevorzugt unter Umlagerung über das intermediäre Naphthylkation 9 zum Naphthylether 22 und zum Naphthyltriflat 24. Der Nachweis von 1-Brom-2,3-dimethylnaphthalin (26) nach Bromidionenzusatz zur Solvolyse bestätigt 9 als reaktive Zwischenstufe. Das (Z)-Triflat 8 solvolysiert bevorzugt zum Eliminierungsprodukt 28, die Bildung des [(3-Methyl-2-naphthyl)methyl]-(trifluorethyl)-ethers (23) kann jedoch nicht über das Kation 9 als Zwischenstufe erklärt werden. Die Solvolyse des Triflates 20 führt ebenfalls zu den Umlagerungsprodukten 22 und 23.
    Additional Material: 1 Tab.
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  • 56
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3160-3164 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Measurement of Absolute Rates of Radical Additions to Alkenes by the “Mercury Method”Using the 5-hexenyl radical (2) as “radical clock” the rates of radical additions to methyl acrylate (5a) and acrylonitrile (5b) are measured by the “mercury method” (Table 1). Alkyl radicals are trapped by the alkylmercury hydride 1 with rate constants of at least 107 1 · mol-1 · s-1.
    Additional Material: 2 Tab.
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  • 57
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    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 58
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3175-3182 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Radical Chain Reactions with Maleic Anhydrides  -  Contrathermodynamic StereoselectivityThe reactions of cyclohexylmercuric chloride with NaBH4 and alkenes 1a-g yield 60-84% of products 3, 4 and 6 in a radical chain process (table 1). Caused by steric effects of substituents Z at least 97% of the radical attack occurs at the unsubstituted carbon atom of maleic anhydrides 1c-g. Only fluoromaleic anhydride 1b is attacked by cyclohexyl radicals predominantly at the substituted carbon atom, because fluorine is a tiny, electron releasing substituent. Radicals 2 are trapped predominantly from the anti-direction by the H-donor (figure 1), yielding cis-compounds 3 as main products. This „contrathermodynamic“ stereoselectivity ranges between 2.3 and 19 (table 1).
    Notes: Die Reaktion von Cyclohexylquecksilberchlorid mit NaBH4 und den Alkenen 1a-g liefert in einer Radikalkettenreaktion die Produkte 3, 4 und 6 in 60- bis 84proz. Ausbeuten (s. Tab. 1). Wegen der sterischen Effekte der Substituenten Z erfolgt der Angriff der Radikale zu mindestens 97% am unsubstituierten C-Atom der Maleinsäureanhydride 1c-g. Allein das Fluormaleinsäureanhydrid 1b wird bevorzugt am substituierten C-Atom durch Cyclohexyl-Radikale angegriffen. Die Ursache für diese umgekehrte Regioselektivität liegt in der geringen Raumerfüllung und dem elektronenspendenden Effekt des Fluoratoms. Die H-Übertragung auf die Radikale 2 erfolgt überwiegend von der anti-Seite (s. Abb. 1), so daß die thermodynamisch instabileren cis-Verbindungen 3 als Hauptprodukte entstehen. Diese „kontrathermodynamische“ Stereoselektivität liegt zwischen 2.3 und 19 (s. Tab. 1).
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  • 59
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1241-1245 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive Platinum Complexes with α-Amino Acid Derivatives and their 31P- and 15N Nuclear Magnetic Resonance SpectraThe α-amino acidate chelate complexes (n-Bu3P)(Cl)⊓PtNH2CH(R)COO (1a - c) (R = H, CH3, CHMe2) react with thionyl chloride, phosphorus pentachloride, or acetyl chloride by cleavage of the chelate ring to give complexes with α-amino acyl chloride or acetic glycine anhydride as ligands: (n-Bu3P)Cl2Pt(NH2CH2COCl) (2), (n-Bu3P)Cl4Pt(NH2CH(CHMe2)COCl) (6), (n-Bu3P)-Cl2Pt(NH2CH2CO(O)OCCH3) (4). Using 15N enriched amino acids, the IR, 15N and 31P NMR spectra indicate cis orientation of phosphane and amino groups in all these complexes.
    Additional Material: 3 Tab.
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  • 60
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1246-1249 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses with Alkenediazonium Salts, III. ω,ω′-Di-1H-1,2,3-triazolylalkanes from Ethenediazonium Hexachloroantimonates and ω,ω′-DiaminoalkanesReaction of the ethenediazonium hexachloroantimonates 2 with ω,ω′-diaminoalkanes 3 leads to ω,ω′-di-1H-1,2,3-triazolylalkanes 5.
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  • 61
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1222-1234 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Boron, 1351). Addition Compounds of 1,3,2-Diazaborolidines with Aluminium and Gallium Halides1,3-Dimethyl-1,3,2-diazaborolidines 3 - 6 add aluminium and gallium halides, respectively, in a 1 : 1 molar ratio. The ligand is monodentate in these coordination compounds (3a - e, 4a, 5a, b, 6a). Addition occurs at one of the ring nitrogen atoms irrespective of the B-substituent. A consequence of this coordination is a long BN bond to the chiral tetracoordinated nitrogen atom as well as a considerable shortening of the BN bond involving the tricoordinate ring nitrogen. In addition, the almost planar five-membered ring adopts the envelope conformation as shown by an X-ray structure analysis of 5a. In contrast, the 2-(dimethylamino)diazaborolidine 7 yields unstable 1 : 1 besides stable 1 : 2 adducts 8. In these the Lewis acid is also coordinated to the ring nitrogen atoms only.
    Notes: Die 1,3-Dimethyl-1,3,2-diazaborolidine 3 - 6 addieren Aluminium- oder Galliumhalogenide im Molverhältnis 1 : 1 zu Koordinationsverbindungen 3a - e, 4a, 5a, b, 6a, in denen der Ligand einzähnig ist. Die Anlagerung erfolgt unabhängig vom B-Substituenten an einem Ringstickstoff-Atom. Folge dieser Koordination ist die Ausbildung einer langen BN-Bindung zum chiralen tetra-koordinierten Ring-Stickstoff, eine erhebliche Verkürzung der BN-Bindung zum dreifach koordinierten endocyclischen Stickstoffatom und der Übergang des nahezu planaren Fünfrings in die „envelope“-Konformation, wie die Röntgenstrukturanalyse von 5a belegt. Im Gegensatz dazu liefert das 2-(Dimethylamino)diazaborolidin 7 mit AlX3 und GaX3 instabile 1 : 1- und stabile 1 : 2-Addukte 8. In diesen ist die Lewis-Säure nur an den Ringstickstoff-Atomen koordiniert.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1250-1254 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Simple Synthesis of Primary Amines via their N,N-Bis(trimethylsilyl) DerivativesPrimary halogen compounds 1 or the corresponding tosylates react with sodium bis(trimethylsilyl)amide (2) in hexamethyldisilazine to form N,N-bis(trimethylsilyl)amines 3, which are converted into the amine hydrochlorides 5 by treatment with aqueous HCl.
    Additional Material: 1 Tab.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1255-1258 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dibenz[a,j]anthracen durch Photocyclodehydrierung von 9,10-Dihydro-2-styrylphenanthrenWährend aus 2-Styrylphenanthren (1) durch Photocyclodehydrierung Benzo[c]chrysen (2) entsteht, läßt sich unter Ausnutzung der „ΣF*-Regel“5) aus 9,10-Dihydro-2-styrylphenanthren (4) durch Photocyclodehydrierung zu 6 und anschließende Dehydrierung Dibenz[a,j]anthracen (3) erhalten.
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  • 64
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1259-1261 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Simple Synthesis of 5-Cyano-2-pyridinecarboxylic Acid and its AmideThe title compounds 3 and 2 (X = CN) are prepared in good yields by regioselective carbamoylation of 3-cyanopyridine in a Minisci reaction and by consecutive amide hydrolysis with amyl nitrite in HCl-saturated acetic acid. The observed regioselectivity apparently remains confined to carbamoyl and possibly acyl radicals and to - M-effect substituents in 3-position.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
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    Topics: Chemistry and Pharmacology
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  • 66
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    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 67
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1424-1435 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Reaction of 2-Pyrrolecarbaldehyde with Hetero-substituted Ethenes3H-Pyrrolizines 1 have been obtained from reactions of 2-pyrrolecarbaldehyde with ethenylphosphonates 2 and the phosphane oxide 5, respectively, the ratio of products depending on the structure of the educts. On varying the reaction conditions a controlled synthesis of both isomers 1e/f was achieved. Pyrrolizines, formed in a reaction of 2 pyrrolecarbaldehyde with ethenyl phenyl sulfone (3), could not be isolated since the reaction proceeded to give more complex pyrrolizine derivatives and the cyclazine 11. A mechanism is proposed for this multistep reaction. N-Alkylation of 2-pyrrolecarbaldehyde with dihaloalkanes has been carried out using phase transfer catalysis.
    Notes: Umsetzungen des 2-Pyrrolcarbaldehyds mit Ethenylphosphonaten 2 und dem Phosphanoxid 5 führten zu 3H-Pyrrolizinen 1, wobei das Mengenverhältnis der gebildeten Isomeren von der Struktur der Edukte abhängt. In einem Falle (1e/1f) gelang die gezielte Synthese beider Isomeren durch Variation der Reaktionsbedingungen. Die aus 2-Pyrrolcarbaldehyd und Ethenylphenylsulfon (3) entstandenen Pyrrolizine 1e/f reagieren weiter unter Bildung komplexer Pyrrolizinderivate und des Cyclazins 11. Für diese Mehrstufenreaktion wird ein Mechanismus vorgeschlagen. Unter Phasentransfer-Bedingungen gelingen Alkylierungen des 2-Pyrrolcarbaldehyds mit Dihalogenalkanen.
    Additional Material: 3 Tab.
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  • 68
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1400-1423 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Anodic Oxidation of OrganoboranesOrganoboranes are converted into more easily oxidizable borates by reaction with nucleophiles and the alkyl groups are dimerized by anodic oxidation. The oxidation potentials (Ep) of the borates depend strongly on the nature of the complexing nucleophile, for instance Ep = +0.37V (vs. SCE) with OH- or +1.65V with tetrahydrofuran. The dimer yields are optimized with trioctylborane (5) by variation of the electrode material and the electrolyte. At the platinum anode in sodium hydroxide-methanol/tetrahydrofuran yields of 80% are obtained for acyclic alkyl groups, and lower ones for cycloalkyl groups. They exceed those obtained by the Kolbe electrolysis or the oxidation with neutral hydrogen peroxide and they are comparable to those of the AgNO3 oxidation. - The selective preparation of unsymmetrical products from borates with different alkyl groups is not possible, the dimerization proceeds likely via free radicals that couple statistically. Good yields of unsymmetrical coupling products are achieved, when one olefin is used in excess. With chloro-, ethoxy-, acetoxy-, and aryl-substituted alkyl groups the dimers are obtained in 21 - 66% yield, with bromide the yield are lower and with nitriles the dimerization fails.
    Notes: Organoborane werden durch Nucleophile in leichter oxidierbare Borate übergeführt und die Alkylreste durch anodische Oxidation dimerisiert. Die Oxidationspotentiale (Ep) der Borate werden stark vom komplexierenden Nucleophil beeinflußt, z. B. Ep = +0.37V (gKE) mit OH- oder + 1.65 V mit Tetrahydrofuran. Mit Trioctylboran (5) werden die Dimerenausbeuten (10) durch Variation von Elektrodenmaterial und Elektrolyt optimiert. An der Platinanode in KOH-Methanol/Tetrahydrofuran liegen die Ausbeuten für acyclische Alkylreste um 80%, die für Cycloalkane niedriger. Sie übertreffen die der Kolbe-Elektrolyse oder der Oxidation mit neutralem Wasserstoffperoxid und sind denen bei der Oxidation mit Silbernitrat vergleichbar. - Die selektive Darstellung unsymmetrischer Produkte aus Boraten mit unterschiedlichen Alkylresten gelingt nicht; die Dimerisierung verläuft wahrscheinlich über freie Radikale, die statistisch kuppeln. Gute Ausbeuten an unsymmetrischen Kupplungsprodukten werden jedoch erzielt, wenn ein Olefin im Überschuß eingesetzt wird. Mit chlor-, ether-, ester- und arylsubstituierten Alkylresten erhält man Dimere mit 21 - 66% Ausbeute. Mit Bromiden gelingt die Kupplung schlecht, mit Nitrilen überhaupt nicht.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2369-2381 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hetero-π-Systems, 9. About the Relationships between Silaethenes and MethylsilylenesSilaethenes 1 and the isomeric methylsilylenes 2 are separately existing species, but can readily be interconverted in an argon matrix via a photochemically induced 1,2-H shift. In case of the thermal excitation in the gas phase examples for both directions have been detected spectroscopically: the isomerisation of a silaolefin into the corresponding silylene (1d → 2d) and the formation of a silene from a silylene (2f → 1f).
    Notes: Die Silaolefine 1 und dazu isomeren Methylsilylene 2 sind getrennt existenzfähige Spezies, lassen sich in einer Argonmatrix aber über eine photochemisch induzierte 1,2-H-Wanderung leicht ineinander umwandeln. Bei thermischer Anregung in der Gasphase ist sowohl die Isomerisierung eines Silaolefins zum zugehörigen Silylen (1d → 2d) als auch eines Silylens zum entsprechenden Silen (2f → 1f) direkt spektroskopisch nachweisbar.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2469-2478 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopropenes as Complex Ligands: η4-Vinylketene Complexes of Manganese, Vanadium, and Cobalt; Preparative and X-ray Crystallographic ResultsThe reaction of 1,2,3-triphenylcyclopropene with (η5-C5H5)Mn(CO)3, (η5-C5H5)V(CO)4, (η5-C5H5)Co(CO)2 and Co2(CO)8 yields via ring opening and carbonylation the new compounds LMn(C5H5)CO (1), LV(C5H5)(CO)2 (2), LCo(C5H5) (3, 4) and L2Co2(CO)4 (6) (L = η4-C3Ph3HCO), respectively. In the reaction with (η5-C5H5)Co(CO)2 additionally the formation of 2,3-diphenylindenone (5) is observed. The X-ray structures of 1, 3 and 5 have been determined.
    Notes: Die Umsetzung von 1,2,3-Triphenylcyclopropen mit (η5-C5H5)Mn(CO)3, (η5-C5H5)V(CO)4, (η5-C5H5)Co(CO)2 und Co2(CO)8 ergibt unter Ringöffnung und Carbonylierung die neuen Verbindungen LMn(C5H5)CO (1), LV(C5H5)(CO)2 (2), LCo(C5H5) (3, 4) bzw. L2CO2(CO)4 (6) (L = η4-C3Ph3HCO). Bei der Reaktion mit (η5-C5H5)Co(CO)2 wird außerdem die Bildung von 2,3-Diphenylindenon (5) beobachtet. Die Röntgenstrukturen von 1, 3 und 5 wurden bestimmt.
    Additional Material: 3 Ill.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2510-2523 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Deamination Reactions, 401). Decomposition of 3,3-, 5,5-, and 7,7-Dimethyl-2-norbornanediazonium Ionsgem.-Dimethylnorbornyl cations (3, 5) were generated by decomposition of optically active diazonium ion precursors. 6,1- and 6,2-H shifts were detected by structural isomerization and racemization, respectively. Product distributions and optical activities were profoundly affected by the polarity of the solvent. In weakly polar solvents, substitution reactions were associated with much less racemization than hydrogen shifts. Our observations are incompatible with equilibrating open ions but are reasonably explained in terms of unsymmetrical ion pairs.
    Notes: gem.-Dimethylnorbornylkationen (3,5) wurden durch Zerfall optisch aktiver Diazonium-Ionen erzeugt. 6,1- und 6,2-H-Verschiebungen wurden durch Strukturisomerisierung bzw. Racemisierung nachgewiesen. Die Polarität des Lösungsmittels hatte einen starken Einfluß auf Verteilung und optische Aktivität der Produkte. In schwach polaren Lösungsmitteln war die Substitution mit deutlich weniger Racemisierung verbunden als die H-Verschiebung. Unsere Beobachtungen sind mit äquilibrierenden, offenen Carbokationen unvereinbar, werden aber durch unsymmetrische Ionenpaare plausibel gedeutet.
    Additional Material: 5 Tab.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2524-2526 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of Carboxylic Acids to (1S)-5,5-Dimethylbicyclo[2.2.1]hept-2-eneProtonation of the title compound 5 induced Wagner-Meerwein rearrangement and 6,2(6,1)-hydride shifts, depending on the polarity of the acid (trifluoroacetic, acetic, and 2-ethylhexanoic acid). The optical purity of 5,5-dimethyl-2-norbornyl esters (7) exceeded that of 7,7-dimethyl-2-norbornyl esters (9). The results are interpreted in terms of asymmetric ion pairs which are tighter than those involved in deamination reactions.
    Additional Material: 1 Tab.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2538-2541 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cesium Effect in C-C-Bond Forming Reactions Yielding Large Hydrocarbon RingsC-C-bond formations of the Wurtz type following the Müller-Röscheisen procedure [alkali metal + tetraphenylethene (TPE)] leading to [2n]paracyclophane rings 2 have been carried out, comparing sodium, potassium, and cesium as metals. As fig. 1 shows, the selectivity of the oligomer formation starting from 1,4-bis(chloromethyl)benzene (1a) is strongly dependent on the alkali metal used. Sodium/TPE besides 2b predominantly yields the higher oligomers 2c - e. Use of cesium metal/TPE leads to 2b preferentially. With potassium metal/TPE all oligomers 2b - e are obtained in low yields or traces, respectively. According to these results, the oligomer formation in carbocyclic ring systems can be steered by the type of alkali metal applied; cesium seems to favour the formation of conformationally more rigid rings (like 2b).
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  • 74
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2580-2596 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramolecular [4 + 3] Cycloaddition of Allylium-2-olates (Oxallyls) to the Furan Nucleus: Synthesis of Oxy-bridged Octahydro-azulenes and -benzocycloheptenesThe grignard reagents prepared from the 2-(ω-chloroalkyl)furans 3b, c can be acylated with the anhydrides or chlorides of chloroacetic, dichloroacetic, and α-chloropropionic acid to form the ω-furyl-substituted α-chloro ketones 1a - d. Treatment of 1 with the lithium perchlorate/triethylamine reagent affords the octahydroepoxyazulenones 2a - c and -1H-benzocycloheptenone 2d, respectively. In the case of 2b and c the exo-connection at C-8a, i.e. trans-anellation of the carbocyclic rings, is preferred.
    Notes: Die aus den 2-(ω-Chloralkyl)furanen 3b, c hergestellten Grignard-Verbindungen können mit den Anhydriden oder Chloriden von Chloressigsäure, Dichloressigsäure und α-Chlorpropionsäure acyliert werden. Die so gebildeten ω-furylsubstituierten α-Chlorketone 1a - d liefern bei der Behandlung mit dem Lithiumperchlorat/Triethylamin-Reagens die Octahydroepoxyazulenone 2a - c und das Octahydroepoxy-1H-benzocycloheptenon 2d. Im Falle von 2b und c ist die exo-Verknüpfung an C-8a, d. h. die trans-Anellierung der carbocyclischen Ringe, bevorzugt.
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  • 75
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2644-2659 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Naphtho[b]cycloheptatrienylidene - a Carbene of the Tropylidene Series with Novel PropertiesNaphtho[b]tropylidene (3) possesses a [15]annulene skeleton. It can be generated by flash solvolysis of the sodium salt of naphthotropone tosylhydrazone (4′) in the gas-phase. Thus 1- and 2-methylanthracene (11 and 12) are formed. The decisive step is a carbene carbene rearrangement to anthrylcarbene 6 and 10, respectively. The reaction is position-selective. Intermediates in these reactions should be the bicyclic compounds 5 and 7. In the condensed phase 3 reacts with olefins to afford cycloaddition products 16 and insertion products 17. The cycloaddition via the intermediate anthrylcarbene 6 to 18 is only a side-reaction. The bicycle system 5 formed in the carbene carbene rearrangement could be trapped by dienes to give 21. Non-stereospecific cycloaddition, allyl insertion as well as competition experiments with olefin/diene mixtures suggest an equilibrium mixture of singlet-3⇄ triplet-3⇄ bicycle 5.
    Notes: Naptho[b]tropyliden (3) besitzt ein [15]Annulen-Gerüst. Es kann durch Blitzthermolyse des Natriumsalzes des Naphthotropon-tosylhydrazons 4′ in der Gasphase erzeugt werden. Hierbei werden 1- und 2-Methylanthracen (11 und 12) gebildet. Als entscheidender Schritt läft dabei eine Carben-Carben-Umlagerung zum Anthrylcarben 6 bzw. 10 ab. Die Reaktion selbst ist positionsselektiv. Als Zwischenstufen dürften die Bicyclen 5 und 7 auftreten. In kondensierter Phase reagiert 3 mit Olefinen unter Bildung von Cycloadditionsprodukten 16 und Insertionsprodukten 17. Die Cycloaddition über das intermediäre Anthrylcarben 6 zu 18 verläuft lediglich als Nebenreaktion. Der in einer Carben-Carben-Umlagerung gebildete Bicyclus 5 konnte durch Diene zu 21 abgefangen werden. Nicht-stereospezifische Cycloaddition, Allylinsertion sowie Konkurrenzexperimente mit Olefin/Dien-Gemischen legen für 3 ein Gleichgewichtsgemisch Singulett-3 ⇄ Triplett-3 ⇄ Bicyclus 5 nahe.
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  • 76
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2622-2643 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Formation and Reactivity of 1-Phosphoryl-1-(phosphoryloxy)allyl Anions and Related CompoundsThe formation of 1-heterosubstituted 1-phosphorylallyl anions of type 1A from the corresponding vinyl or allyl phosphonates is described. The reactivity in reactions with alkyl halides and carbonyl compounds is investigated. For preparative purposes neither the sulfur derivative 11A nor the oxygen derivatives 16A, 19A, 23A, and 29A show sufficiently high reactivity and selectivity. Only the 3-silylated derivative 25A reacts regioselectively with carbonyl compounds via Wittig-Horner olefination to give functionalized dienes 26 in moderate yields. From those it is possible to remove the phosphoryl, silyl or phosphoryloxy group selectively. Reactivity of dienes 26 in Diels-Alder reactions is poor.
    Notes: Die Bildung von in 1-Stellung heterosubstituierten 1-Phosphoryl-allyl-Anionen vom Typ 1A aus den entsprechenden Vinyl- oder Allylphosphonaten wird beschrieben und ihre Reaktivität gegenüber Alkylhalogeniden und Carbonylverbindungen untersucht. Weder das Schwefel-Derivat 11A noch die Sauerstoff-Derivate 16A, 19A, 23A und 29A besitzen für präparative Nutzung hinreichend hohe Reaktivität und Selektivität. Nur das in 3-Stellung silylierte Derivat 25A reagiert mit Carbonylverbindungen regioselektiv unter Wittig-Horner-Olefinierung in befriedigenden Ausbeuten zu den funktionalisierten Dienen 26. Aus diesen läßt sich selektiv die Phosphoryl-, die Silyl- oder Phosphoryloxygruppe abspalten. Die Reaktivität der Diene 26 in Diels-Alder-Reaktionen ist gering.
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  • 77
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2693-2702 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Low Coordinated Phosphorus Compounds, 27. Synthesis and Reactions of EthynylphosphaalkenesReactions of the alkyne grignards 2a, b with P-chlorophosphaalkenes 1a, b yield the ethynylphosphaalkenes 5a - d in high yields. 5a, b, d undergo [2 + 2]-cycloaddition forming the 1,3-diphosphetanes 7a, b, d. The structures of 7 are confirmed by NMR spectroscopy and, in part, by X-ray structure determination. With 2,3-dimethyl-1,3-butadiene 5a - d form the 1,2,3,6-tetra-hydrophosphinines 8a - d via [2 + 4]-cycloaddition.
    Notes: Die Umsetzung der P-Chlorphosphaalkene 1a, b mit den Grignard-Alkinen 2a, b liefert die Ethinylphosphaalkene 5a - d in hoher Ausbeute. Durch [2 + 2]-Cycloaddition entstehen daraus 1,3-Diphosphetane 7a, b, d, deren Struktur mittels NMR-Spektroskopie und Röntgenbeugung ermittelt wurde. Mit 2,3-Dimethyl-1,3-butadien erfolgt [2 + 4]-Cycloaddition zu den 1,2,3,6-Tetrahydrophosphininen 8.
    Additional Material: 3 Ill.
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  • 78
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2745-2760 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure of 2,6-Dicyanobicyclo[3.3.1]nona-2,6-dienes and 2,6-DicyanobarbaralanesThe zinc iodide-catalyzed addition of trimethylsilyl cyanide to bicyclo[3.3.1]nonane-2,6-dione (5) yields the sterically defined O-silylated cyanohydrin 9. Trichlorophosphane oxide in pyridine converts the latter to the unsaturated dinitrile 7c. Depending on the amount of N-bromosuccinimide used, the bromination of the dinitrile 7c affords either a mixture of the monobromo- (10) and the dibromodinitrile 7d or pure dibromodinitrile 7d. With sodium methoxide in methanol the monobromodinitrile 10 is converted via concerted dehydrobromination to 2,6-dicyanobarbaralane (8c) The latter is formed almost quantitatively on debromination of the dibromodinitrile 7d with zinc/copper reagent, while sodium methoxide yields the 4-bromo-2,6-dicyanobarbaralane (12). All reactions proceed smoothly in high yields. X-ray structural parameters for bicyclo[3.3.1]nona-2,6-dienes (i. e. 7c, d and 10) and a barbaralane (i. e. 12) have for the first time become available.
    Notes: Zinkiodid-katalysierte Addition von Trimethylsilylcyanid an Bicyclo[3.3.1]nonan-2,6-dion (5) ergibt das sterisch einheitliche O-silylierte Cyanhydrin 9, das mit Trichlorphosphanoxid in Pyridin zum ungesättigten Dinitril 7c umgesetzt wird. Je nach N-Bromsuccinimid-Menge entsteht bei der Bromierung des Dinitrils 7c ein Gemisch aus Monobrom- (10) und Dibromdinitril 7d oder reines Dibromdinitril 7d. Das Monobromdinitril 10 wird durch eine konzertierte Dehydrobromierung mit Natriummethanolat in Methanol in das 2,6-Dicyanbarbaralan (8c) übergeführt. Dieses bildet sich fast quantitativ durch Debromierung des Dibromdinitrils 7d mit Zink/Kupfer, während die Dehydrobromierung von 7d mit Natriummethanolat in Methanol 4-Brom-2,6-dicyanbarbaralan (12) ergibt. Alle Reaktionen verlaufen sehr glatt und mit hohen Ausbeuten. Durch Röntgenstrukturbestimmung der Dinitrile 7c, d und 10 sowie des 4-Brom-2,6-dicyanbarbaralans (12) wurden die exo-Konfiguration der Bromatome von 7d und 10 und erstmal geometrische Parameter von Bicyclo[3.3.1]nona-2,6-dienen und einem Barbaralan ermittelt.
    Additional Material: 5 Ill.
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  • 79
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2761-2778 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Photochemical Elimination of Nitrogen from 1-(1-Alkenyl)-4-tert-butyl-1,4-dihydro-5H-tetrazol-5-ones. Competition between Addition of Methanol and Cyclization of a Dipolar IntermediateThe 4-tert-butyl-1-vinylterazolones 12a - c and the tetrazolones 13 and 14 are synthesized from the 5-chlorotetrazole 7 and the tetrazolone 9 via several routes. Bis(benzonitrile)palladium dichloride catalyses the O → N-Claisen rearrangement 8 → 11, the allyl → vinyl rearrangements 11a → 12b and 11b → 12c, as well as the equilibration 13 → 14. On 254 nm photolysis of the vinyltetrazolones 12 nitrogen is extruded and cyclic and/or acylic products of primary photo-intermediates are formed: In [D3]acetonitrile as solvent, 77% of 1-tert-butylimidazolone 16 arises from 12a, while the tetrazolones 12b, c produce only complex mixtures. In methanol as solvent, the methanol adduct 20a (23%) of the intermediate imidazolone 15a and the acyclic N-(1,2-dimethoxyethyl)urea 22a (32%) are obtained besides 45% of 16. In contrast, from 12c in methanol the corresponding urea 22c is formed almost quantitatively as the only product. In [D4]methanol solution of (E,Z)-12b a ratio of 4-methoxyimidazolidinone 20 b to the diastereomeric ureas 22 b of 22: 78 is observed. With decreasing amounts of [D4]methanol in [D4]methanol/[D3]acetonitrile mixtures, the imidazolidinone 20 b increases at the expense of the ureas 22 b. A 20 b: 22 b ratio of 98: 2 is reached in [D3]acetonitrile containing 3-6% [D4]methanol. This indicates a competition between the cyclization (affording 20 b via 15 b) and the methanol addition (producing 22 b via 21 b) of a dipolar photo-intermediate. The structure of the photo-products are confirmed by independent synthesis of 16 and by their high field proton and carbon-13 NMR spectra.
    Notes: Aus dem 5-Chlortetrazol 7 und dem Tetrazolon 9 werden auf verschiedenen Wegen die 4-tert-Butyl-1-vinyltetrazolone 12a - c sowie die Tetrazolone 13 und 14 hergestellt. Bei der 254-nm-Photolyse der 1-Vinyltetrazolone 12 erhält man in Abhängigkeit von Struktur und Reaktionsbedingungen das Imidazolon 16, die 4-Methoxyimidazolidinone 20 und/oder die N-(1,2-Dimethoxyalkyl)harnstoffe 22. Die Ergebnisse sprechen für eine Konkurrenz zwischen Cyclisierung (→ 15b → 20b) und Methanol-Addition (→ 21b → 22b) einer dipolaren Photozwischenstufe. Die Struktur der Photoprodukte wird durch unabhängige Synthese von 16 sowie Hochfeld-1H-und 13C-NMR-Spektren bewiesen.
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. XXIII 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 81
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3169-3174 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organometallic Lewis Acids, XV1). Cyclodimerization of 2-Butyne and 2-Pentyne at Pentacarbonyl(tetrafluoroborato)rhenium to a Coordinated Methylenecyclobutene DerivativeThe reactions of pentacarbonyl(tetrafluoroborato)rhenium, (OC)5ReFBF3 (1a), with 2-butyne and 2-pentyne give the methylenecyclobutene complexes [(CO)5Re(C8H12)]+BF4- (2) and [(CO)5Re(C10H16)]+BF4- (3). From 2, 3 the methylenecyclobutene ligands can be liberated by halide ions.
    Additional Material: 1 Tab.
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  • 82
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Metal π-Complexes of Benzene Derivatives, XXIV1). 1H NMR Coordination Shift and Ring Current Quenching in Sandwich Complexes as Studied for Bis(η6-[10]paracyclophane)chromium(0)The title compound was prepared by means of metal atom-ligand vapor cocondensation. Its most conspicuous feature, the well defined disposition of 20 methylene groups in the periphery of the title complex is employed to gauge via 1H NMR the coordination induced quenching of the aromatic ring current in arenes.
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  • 83
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3194-3204 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gas Phase Chemistry of Metastable Thiophene Cation RadicalsThe unimolecular loss of acetylene from metastable thiophene cation radicals (1) has been studied by means of 13C and deuterium labelling and semi-empirical molecular orbital calculations (MINDO/3). It is shown that direct loss of acetylene from unrearranged 1 amounts to less than 5.3%:1.2% involving C-α/C-β and 4.1% for loss of C-β/C-β for dissociations with lifetimes t ≈ 10-5.5s. More than 94% of the long-lived molecular ions rearrange prior to dissociation, and it is shown that the majority of 1 (64.5%) undergoes complete carbon atom scrambling, presumably via the tricyclic cation radical 12. 30.2% of 1 suffer a degenerate isomerization involving either the pyramidal cation radical 11 or the bicyclic cation radicals 13, the latter undergoing a “Merry-go-round” rearrangement. At shorter lifetimes of 1 (t ≈ 10-6.5S) the isomerization pattern is only slightly changed. In agreement with previous kinetic studies of Butler and Baer8) it is shown by collisional activation mass spectrometry and the MINDO/3-study that the structure of the C2H2S+. ion generated from 1 is best described as that of the thioketene cation radical (18) and not of the isomeric mercaptoacetylene 21. The loss of both deuterated and 13C-labelled acetylene from labelled 1 is subject to a kinetic isotope effect.  -  The syntheses of the various isotopomers are described.
    Notes: Die unimolekulare Acetylen-Eliminierung aus den metastabilen Molekül-Ionen des Thiophens (1) wird durch eine Kombination von MINDO/3-Rechnungen und 13C- und D-Markierung analysiert. Es wird gezeigt, daß Ionen mit einer Lebensdauer von ca. 10-5.5 s nur untergeordnet zu einem direkten Zerfall befähigt sind: 1.2% für die C2H2-Abspaltung aus der C-α/C-β- und 4.1% für die aus der C-β/C-β-Position. Mehr als 94% der metastabilen Ionen erleiden vor ihrem Zerfall eine Isomerisierung, die zu 64.5% über das tricyclische Radikalkation 12 verläuft. Die Umlagerung über das pyramidale Ion 11 oder in Form einer „Merry-go-round“-Isomerisierung über 13 findet zu 30.2% statt. Bei kürzeren Zerfallszeiten (t ≈ 10-6.5s) ändert sich das Verhalten von 1 nicht wesentlich. In Übereinstimmung mit den kinetischen Untersuchungen von Butler und Baer8) belegen sowohl unsere Stoßaktivierungsuntersuchung als auch die MINDO/3-Analyse, daß den resultierenden C2H2S+.-Ionen die Struktur eines Thioketen-Radikalkations (18) und nicht des isomeren Mercaptoacetylens (21) zukommt. Der Verlust von deuteriertem bzw. 13C-markiertem Acetylen ist mit einem kinetischen Isotopieeffekt verknüpft.  -  Die Synthesen der verschiedenen Isotopomeren werden beschrieben.
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  • 84
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (η2-Alkene)(η5-cyclopentadienyl)organylnickel ComplexesThe (cyclopentadienyl)organylnickel species A, which is formed by reaction of nickelocene (1) with organolithium or organomagnesium halides, can be stabilized by complexation to the C = C bond of an olefin. Below ca. -30°C, the organyllithium compounds react with 1 and olefins to give the (η2-alkene)(η5-cyclopentadienyl)organylnickel complexes 2a-j (alkene: ethylene), 7-14 (alkene: propene) as well as the related methylnickel derivatives 15-17 and 22-25 with alkenes of different types.  - Only one C=C bond of butadiene complexes to give 18, while in the case of substituted 1,3-alkadienes the least substituted double bond is complexed. Temperature dependent NMR spectra are observed; in the case of the CH2=CHR and CH2=CR1R2 complexes as the result of rotation of the alkene around the coordination axis two rotamers can be observed at ca. -60°C. The ability of the organylnickel bond to add to complexed ethylene decreases in the order Ph-Ni (to 28) 〈 c-C3H5-Ni (to 29) 〈 Me-Ni (to 2e). 2d catalyzes the oligomerisation of ethylene at 120°C to give a mixture of butene, hexene, and octene.
    Notes: Das bei der Umsetzung von Nickelocen (1) mit Organylmagnesiumhalogenid bzw. Organyllithium primär entstehende (Cyclopentadienyl)organylnickel A läßt sich durch Komplexierung an die C = C-Bindung eines Olefins stabilisieren. Unterhalb ca. -30°C lassen sich mit Organyllithium die (η2-Alken)(η5-cyclopentadienyl)organylnickel-Komplexe 2a-j (Alken: Ethylen), 7-14 (Alken: Propen) sowie die Methylnickel-Derivate gleichen Typs 15-17 und 22-25 mit verschiedenartigen Alkenen erhalten. Bei Butadien komplexiert nur eine C = C-Bindung zu 18, bei unsymmetrisch substituierten Butadienen ist dies die geringer substituierte Bindung.  -  Rotation des Alkens um die Koordinationsbindungsachse bedingt temperaturabhängige NMR-Spektren; bei Alkenen der Typen CH2=CHR und CH2=CR1R2 sind bei ca. -60°C zwei Rotamere beobachtbar. Die Fähigkeit der Organyl-Nickel-Bindung zur Addition an komplexiertes Ethylen sinkt in der Reihe Ph-Ni (zu 28) 〈 c-C3H5-Ni (zu 29 〈 Me-Ni (zu 2e). 2d katalysiert bei 120°C die Oligomerisierung von Ethylen zu einem Gemisch von Buten, Hexen und Octen.
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  • 85
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    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3320-3324 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reductive Displacement of the Acetate Group in Allyl, Propargyl, and Benzyl Acetates by NaBH4/NiCl2 · 6 H2OThe combination of NiCl2 · 6 H2O and NaBH4 provides an effective system for reductive removal of the acetate group of allyl, propargyl, and benzyl acetates. Sterically less hindered allyl acetates are converted preferentially to the corresponding alkanes (Table 1).
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 117 (1984) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 87
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Aziridines, 301).  -  Synthesis of 2-(Acylimino)pyrrolidines and N-Acylated γ-Aminobutyronitriles by Amidoethylation of Simple Nitriles with N-AcylaziridinesMono- and disubstituted acetonitriles 3a-j in their deprotonated from are amidoethylated at the α-carbon with the N-acylaziridines 5a-d under aprotic conditions. The anionic primary products 6 and 20e, i may undergo a second amidoethylation if derived from a mono-substituted acetonitrile, and they may cyclize followed by migration of the acyl group. Thus, the N-acylated α-substituted γ-aminobutyronitriles 7b-g, i-o, the N,N'-diacylated 1,5-diamino-3-cyanopentanes 15d, f, g and 22e, i, the 2-(acylimino)pyrrolidines 10a-c, e, f, h-j, and the 3-amidoethylated 2-(acylimino)pyrrolidines 16e, f, h, i are obtained. Once, 6 was a second time amidoethylated at the amide nitrogen. In one case, the 3-cyano-2-pyrrolidone 25 was formed by amidoethylation, elimination of Ph2N⊝, and cyclization of the intermediate isocyanate. The cyclization may be prevented by using lithium as gegenion or by using a protic solvent. Base catalyzed solvolysis of an (acylimino)pyrrolidine removes the acyl group if this is ethoxycarbonyl and cleaves the C=N double bond if the acyl group is benzoyl.
    Notes: Mono- und Disubstituierte Acetonitrile 3a-j werden nach Deprotonierung unter aprotischen Bedingungen durch die N-Acylaziridine 5a-d am α-C-Atom amidoethyliert. Die anionischen Primärprodukte 6 und 20e, i können bei monosubstituierten Acetonitrilen (3d-i) einer zweiten Amidoethylierung unterliegen und können allgemein unter Cyclisierung und Acylwanderung weiterreagieren. Dementsprechend erhält man die N-acylierten α-substituierten γ-Aminobutyronitrile 7b-g, i-o, die N,N'-diacylierten 1,5-Diamino-3-cyanpentane 15d, f, g und 22e, i, die 2-(Acylimino)pyrrolidine 10a-c, e, f, h-j und die in 3-Stellung amidoethylierten 2-(Acylimino)pyrrolidine 16e, f, h, i. Einmal wurde 6 am Amidstickstoff ein zweites Mal unter Bildung von 13 amidoethyliert. In einem Falle wurde durch Amidoethylierung, Eliminierung von Ph2N⊝ und Cyclisierung des intermediär gebildeten Isocyanats das 3-Cyan-2-pyrrolidon 25 gebildet. Die Cyclisierung läßt sich verhindern mit Lithium als Gegenion oder durch Verwendung eines protischen Lösungsmittels. Basenkatalysierte Solvolyse eines (Acylimino)pyrrolidins entfernt den Acylrest, wenn dieser Ethoxycarbonyl ist, und spaltet die C=N-Doppelbindung, wenn der Acylrest Benzoyl ist.
    Additional Material: 7 Tab.
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  • 88
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3400-3413 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Oligophosphaalkanes, VI1). Syntheses and NMR Spectroscopic Characterization of PH-functional Methylene Bridged Diphosphanes R2P-CH2-PRH and HRP-CH2-PRH1,3-Diphosphapropane, H2P-CH2-PH2 (1) was synthesized in about 40% yield by reduction of Cl2P-CH2-PCl2 with LiAlH4. The mono-, di-, and tri-substituted derivatives RHP-CH2-PH2 (R = iPr, CH2Ph, 3a, b) RHP-CH2-PHR (R = iPr, CH2Ph, tBu, 5a-c), R2P-CH2-PRH (R = Me, iPr, CH2Ph, 10b, 7a, b) are accessible using Cl2P-CH2-PCl2 as a starting material. A multiple stage synthesis based on MePCl2 affords the disecondary phosphane MeHP-CH2-PmeH (10d), which in contrast to reports given in the literature is thermally stable to at least 100°C. The 31P and 1H NMR spectra of 1 have been analyzed and simulated by use of computer programs. The structure of the phosphanes is discussed on the basis of their 1H, 31P{1H}, 31P, and 13C{1H} NMR spectra.
    Notes: 1,3-Diphosphapropan, H2P-CH2-PH2 (1), läßt sich durch Reduktion von Cl2P-CH2-PCl2 mit LiAlH4 in ca. 40proz. Ausbeute darstellen. Mono-, Di- und Trisubstitutionsprodukte RHP-CH2-PH2 (R = iPr, CH2Ph, 3a, b), RHP-CH2-PHR (R = iPr, CH2Ph, tBu, 5a-c), R2P-CH2-PRH (R = Me, iPr, Ch2Ph, 10b, 7a, b) des Grundkörpers 1 dieser Serie sind ausgehend von Cl2P-CH2-PCl2 zugänglich. Eine Mehrstufensynthese auf der Basis von MePCl2 liefert das disekundäre Phosphan MeHP-CH2-PMeH (10d), das im Gegensatz zu Berichten in der Literatur thermisch bis zu 100°C stabil ist. Die 31P- und 1H-NMR-Spektren von 1 wurden analysiert und rechnerisch simuliert. Die Struktur der Phosphane wird anhand ihrer 1H-, 31P{1H}-, 31P- und 13C{1H}-NMR-Spektren diskutiert.
    Additional Material: 2 Ill.
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  • 89
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 3443-3456 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: (Cyclopentadienyl)organylcobalt ComplexesReaction of cobalticinium chloride (1) with organometallic compounds of Li, Mg, Al, and Zn leads (depending upon the metal, the organic group, the solvent, and the reaction temperature) to the formation of the (η5-cyclopentadienyl)(η4-5-organyl-1,3-cyclopentadiene)cobalt complexes 4a-j or cobaltocene (2) or mixtures of both. The exclusive formation of the exo-5-organyl derivatives 4 suggests a mechanism involving a cobalticinium chloroorganometallate species 3 or a cobalticinium alkanide species C. Complexes 3 were isolated from the reaction with aluminium or zinc compounds. Solvated cobalticinium salts of type C were identified in the reactions of 1 with sodium methoxide or ethoxide. They react further to (η5-cyclopentadienyl)(η4-exo-5-alkoxy-1,3-cyclopentadiene)cobalt complexes 6 upon removing the solvating alcohol.  -  In contrast to the unstable bis(cyclopentadienyl)organylcobalt complexes B (which react further to 2), the corresponding organylcobalt complexes 8a-f were obtained from the reaction of (η3-allyl)(η5-cyclopentadienyl)cobalt bromide 7 with organolithium or -magnesium halides. At 20°C 8d isomerizes by coupling of the vinyl and the allyl group into the (η4-1,3-pentadiene)cobalt complexes 9a and b.
    Notes: Bei der Umsetzung von Cobalticiniumchlorid (1) mit Organyl-Verbindungen von Li, Mg, Al oder Zn entstehen, abhängig vom Metall, dem Organylrest, dem Lösungsmittel und der Reaktionstemperatur die (η5-Cyclopentadienyl)(η4-5-organyl-1,3-cyclopentadien)cobalt-Komplexe 4a-j oder Cobaltocen (2) bzw. deren Mischungen. Aus der ausschließlichen Bildung der exo-5-Organylderivate 4 wird auf einen Reaktionsverlauf über Cobalticinium-chloroorganylmetallate 3 und/oder Cobalticinium-alkanide C geschlossen. Komplexe 3 konnten mit Aluminium- und Zinkverbindungen erhalten werden. Cobalticiniumsalze des Typs C wurden bei der Umsetzung von 1 mit Natriummethylat oder -ethylat als Solvat-Komplexe 5 nachgewiesen, die beim Entfernen des Solvatalkohols in (η4-exo-5-Alkoxy-1,3-cyclopentadien)(η5-cyclopentadienyl)cobalt-Komplexe 6 übergehen.  -  Im Gegensatz zu den instabilen Bis(cyclopentadienyl)organylcobalt-Komplexen B, die unter Bildung von 2, zerfallen, können durch Umsetzung von (η3-Allyl)(η5-cyclopentadienyl)-cobaltbromid (7) mit Organolithium oder -magnesiumhalogeniden entsprechende Organocobalt-Komplexe 8a-f erhalten werden. 8d isomerisiert bei 20°C unter Verknüpfung von Vinyl- und Allylgruppe zu den (η4-1,3-Pentadien)cobalt-Komplexen 9a und b.
    Additional Material: 7 Tab.
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  • 90
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    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1113-1127 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Complex Formation of Phenyl- and (4-Phenylbutyl)-substituted Crown EthersA number of phenyl and (4-phenylbutyl) derivatives of 18-C-6 and 24-C-8 have been prepared: tetraphenyl-diene-18-crown-6 (TPDE-18-C-6), tetraphenyl-18-crown-6 (TP-18-C-6), tetraphenyl-diene-24-crown-8 (TPDE-24-C-8), tetraphenyl-24-crown-8 (TP-24-C-8), and bis(4-phenylbutyl)-18-crown-6 (BPB-18-C-6). The ring formation reactions have been carried out by phase-transfer catalysis. All compounds are solids at room temperature except for the liquid BPB-18-C-6 which represents a mixture of isomers. The syn- and anti-isomers of TP-18-C-6 and TP-24-C-8 have been isolated and identified by x-ray diffraction. The complex formation constants, determined by d. c. polarography in methanol/benzene (80 : 20 v/v), depend not only on the ring size but also on the number and kind of substituents as well as their steric arrangement. The derivatives of 18-C-6 form the most stable complexes with K+, Sr2+, Ba2+, and Pb2+. The derivatives of 24-C-8 prefer K+, Rb+, and Ba2+.
    Notes: Es wird eine Anzahl phenyl- und (4-phenylbutyl)-substituierter Derivate von 18-C-6 und 24-C-8 dargestellt: Tetraphenyl-dien-18-krone-6 (TPDE-18-C-6) (1), Tetraphenyl-18-krone-6 (TP-18-C-6), (2a, b), Tetraphenyl-dien-24-krone-8 (TPDE-24-C-8) (3), Tetraphenyl-24-krone-8 (TP-24-C-8) (4a, b) und Bis(4-phenylbutyl)-18-krone-6 (BPB-18-C-6) (5). Die Ringschlüsse erfolgen mit Hilfe der Phasentransferkatalyse. Mit Ausnahme des flüssigen BPB-18-C-6, das als Isomerengemisch vorliegt, sind alle anderen Verbindungen bei Raumtemperatur fest. Bei TP-18-C-6 und TP-24-C-8 werden die syn- bzw. anti-Isomeren getrennt und mit Hilfe der Röntgenstrukturanalyse identifiziert. Die durch Gleichstrompolarographie bestimmten Komplexbildungskonstanten in Methanol/Benzol (80 : 20 v/v) sind nicht nur von der Ringgröße, sondern auch von der Zahl und Art der Substituenten sowie der geometrischen Anordnung abhängig. Die 18-C-6-Derivate bilden die stabilsten Komplexe mit K+ bzw. Sr2+, Ba2+ und Pb2+. Die 24-C-8-Derivate bevorzugen K+, Rb+ bzw. Ba2+.
    Additional Material: 6 Ill.
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  • 91
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Über den Mechanismus der Bildung von Umlagerungsprodukten bei der Addition von Arensulfenylchlorid und 4-Phenyl-4H-1,2,4-triazol-3,5-dion an BenzonorbornadieneAufgrund von Produkt- und Geschwindigkeitsuntersuchungen wurde ein ähnliches Verhalten von Phenyltriazoldion (PTAD) und den Arensulfenylchloriden 10 und 11 bei der elektrophilen Addition an die Benzonorbornadiene 1, 8 und 9 festgestellt, wobei die Umlagerungsprodukte 2 bzw. 6 entstehen. In Analogie zu dem gesicherten Mechanismus eines elektrophilen 3-Zentren-Angriffs bei der Reaktion der Arensulfenylchloride wird für die PTAD-Reaktion ein Ablauf über das Aziridinium-Ion 4 als Zwischenstufe vorgeschlagen. Daβ dennoch im Fall des PTAD weder Regioselektivität noch Abfangreaktionen und auch kein Additionsprodukt ohne Umlagerung beobachtet werden konnten, wurde mit Hilfe elektronischer und sterischer Effekte am dipolaren Aziridinium-Molekül gedeutet. - Die Röntgenstrukturanalyse des aus 9 und 11 erhaltenen Additionsprodukts 17 wird mitgeteilt.
    Notes: On the basis of product and rate studies the similarity in the electrophilic addition of phenyl-triazolediones (PTAD) and the arenesulfenyl chlorides 10 and 11 to benzonorbornadienes 1, 8, and 9, giving the rearrangement products 2 and 6, respectively, is being recognized. In analogy to the established mechanism involving three-center electrophilic attack for the arenesulfenyl chloride reaction, the PTAD reaction is proposed to proceed via the aziridinium ion 4 as intermediate. The lack of trapping, of regioselectivity and of formation of addition product in the case of PTAD is interpreted in terms of electronic and steric effects on the dipolar aziridinium species. - An x-ray analysis of the addition product 17, derived from 9 and 11, is reported.
    Additional Material: 2 Ill.
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  • 92
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1178-1193 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Azine Complexes of the (Pentamethylcyclopentadienyl)germanium and -tin CationBecause of their electrophilicity the cationic (h5-pentamethylcyclopentadienyl)germanium and -tin units react with pyridine, pyrazine, and 2,2′-bipyridine to form adducts 2 - 4. X-ray structure studies of the pyridine and bipyridine complexes of the C5Me5Sn+ cation (2b, 4b) show a distortion of h5-bonding towards h2- and h3-structures. The structural consequences of the complexation reaction can be understood in terms of the frontier orbitals of the compounds.
    Notes: Die kationische (h5-Pentamethylcyclopentadienyl)germanium- bzw. -zinn-Einheit reagiert aufgrund ihrer Elektrophilie mit Pyridin, Pyrazin sowie mit 2,2′-Bipyridin unter Bildung von Addukten 2 - 4. Röntgenstrukturanalytische Untersuchungen am Pyridin- sowie am Bipyridinkomplex des C5Me5Sn+ -Kations (2b, 4b) lassen eine Verzerrung der ursprünglichen h5-Bindung in Richtung auf eine h2- bzw. h3-Struktur erkennen. Die Strukturellen Konsequenzen der Komplexbildungsreaktione werden im Rahmen einer Diskussion der Grenzorbitale der Komponenten verständlich.
    Additional Material: 8 Ill.
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  • 93
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1153-1160 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On the Way to Pentafluorocyclopentadienyl Anion: 1,2,3,4,5-Pentafluorocyclopentadiene1,2,3,4,5-Pentafluorocyclopentadiene (8) was obtained in three steps from hexachlorocyclopentadiene (2). It is a typical cyclopentadiene. Thus, it dimerizes reversibly already at - 78°C.
    Notes: 1,2,3,4,5-Pentafluorcyclopentadien (8) wurde in drei Stufen aus Hexachlorcyclopentadien (2) hergestellt. Es ist ein typisches Cyclopentadien. So dimerisiert es - reversibel - bereits bei - 78°C.
    Additional Material: 1 Ill.
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  • 94
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metallkomplexe von Cyanamiden und ihre Alkylierung zu Cyanamidiumsalzen. Eine allgemeine Synthese hochsubstituierter Harnstoffe, Isoharnstoffe und GuanidineAus disubstituierten Cyanamiden und Lewis-Säuren werden die Komplexe 3a - p erhalten. Nach einer Röntgenstrukturanalyse hat der Antimonpentachlorid-Komplex 3a weder s̰- noch π-Symmetrie ( ∡ C≡N - Sb 133°). Die Komplexe 3 mit SbCl5 oder FeCl3 können mit tertiären Alkylchloriden zu den kristallinen Cyanamidiumsalzen 5a - m alkyliert werden. Mit Wasser, primären oder sekundären Alkoholen reagieren die Verbindungen 5 zu Harnstoffen (11) bzw. Uroniumsalzen (8a - z), mit Ammoniak, primären oder sekundären Aminen zu Guanidiniumsalzen (9a - s).
    Notes: The complexes 3a - p were prepared from disubstituted cyanamides and Lewis acids. According to a X-ray structural analysis, the antimony pentachloride complex 3a is neither a s̰ nor a π complex (∡ C≡N - Sb 133°). The complexes 3 with SbCl5 and FeCl3 can be alkylated with tertiary alkyl chlorides, affording crystalline cyanamidium salts (5a - m) which were characterized by reactions with water, primary or secondary alcohols to give ureas (11) and uronium salts (8a - z), respectively. The guanidinium salts 9a - s were obtained with ammonia, primary and secondary amines.
    Additional Material: 1 Ill.
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  • 95
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1194-1214 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 1,3-Dipolar Cycloadditions, 911). The Chemistry of N-Methyl-C-phenylnitrilimineThe treatment of N′-[α-bromobenzylidene]-N-methylhydrazinium bromide, accessible by bromination of benzaldehyde-N-methylhydrazone, with triethylamine furnishes the title compound; this method is superior to the thermolysis and photolysis of 2-methyl-5-phenyltetrazole. The in situ cycloadditions of the 1,3-dipole to arylethylenes, cyclohexene, and α,β-unsaturated carboxylic esters furnish derivatives of 1-methyl-3-phenyl-2-pyrazoline; the structures are elucidated and the isomer ratios determined. Phenylacetylen and acetylenic carboxylic esters likewise add the nitrilimine in both directions providing pyrazoles. The regiochemistry of N-methyl-C-phenylnitrilimine is compared with that of other nitrilimines and of benzonitrile oxide. Some nitriles and carbon disulfide serve as dipolarophiles with hetero-multiple bond.
    Notes: Aus N′-[α-Brombenzyliden]-N-methylhydraziniumbromid, durch Bromierung des Benzaldehyd-N-methylhydrazons erhalten, wird mit Triethylamin die Titelverbindung freigesetzt; diese Methode ist der Thermolyse oder Photolyse des 2-Methyl-5-phenyltetrazols überlegen. Die in situ-Cyclo-additionen des 1,3-Dipols an Arylethylene, Cyclohexen sowie ethylenische Carbonsäureester führen zu 1-Methyl-3-phenyl-2-pyrazolin-Abkömmlingen, die strukturell geklärt und im Isomeren-Verhältnis bestimmt werden. Auch Phenylacetylen und acetylenische Carbonsäureester lagern das Nitrilimin in beiden Richtungen unter Bildung von Pyrazolen an. Die Regiochemie der Additionen des N-Methyl-C-phenylnitrilimins wird mit der anderer Nitrilimine und der des Benzonitriloxids verglichen. Einige Nitrile und Schwefelkohlenstoff dienen als Dipolarophile mit Heteromehrfachbindung.
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  • 96
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1671-1678 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die entartete Cope-Umlagerung des 2,6-BarbaralandicarbonitrilsDie 1H- und 13C-NMR-Spektren von 4-Brom-2,6-barbaralandicarbonitril (2b) wurden vollständig analysiert. Das Molekül existiert nur in einer einzigen valenztautomeren Form. Die chemischen Verschiebungen im 13C-NMR-Spektrum von 2b dienen zur Abschätzung der analogen Verschiebungen des nicht-umlagernden Valenztautomeren des 2,6-Barbaralandicarbonitrils (2a). Die Barriere der entarteten Cope-Umlagerung von 2a in [D2]Dichlormethan wurde durch Messungen der Linienbreite im Temperaturbereich 204 - 249 K zu δG206± = 24.2 kJ. mol-1 bestimmt. Das Festkörper-13C-NMR-Spektrum von 2a zeigt, daß sich der größte Teil der Probe bei Raumtemperatur nicht rasch umlagert.
    Notes: The 1H and 13C NMR spectra of 4-bromo-2,6-barbaralanedicarbonitrile (2b) were completely analysed and the molecule is shown to exist as a single valence tautomer. The 13C chemical shifts of 2b serve as estimates of the analogous shifts in the non-exchanging valence tautomer of 2,6-barbaralanedicarbonitrile (2a) itself. The barrier for the degenerate Cope rearrangement of 2a in [D2]dichloromethane has been determined from line width measurements in the temperature range 204 - 249 K to be δG206† = 24.2 kJ. mol-1. The solid state 13C NMR spectrum of 2a indicated that the bulk of the sample is not undergoing rapid rearrangement at room temperature.
    Additional Material: 2 Ill.
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  • 97
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1679-1694 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Milde und effektive Abspaltung von Dithioketal-Schutzgruppen durch Triarylamin-Radikalkationen als homogene Elektronenüberträger1,3-Dithiane 2 können durch eine äußerst milde oxidative Methode unter Verwendung von Tri-p-tolylammoniumyl (1a+.) oder Tris(4-bromphenyl)ammoniumyl (1b+.) also homogene Elektronenüberträger in effektiver Weise in die zugrunde liegenden Carbonylverbindungen 7 umgewandelt werden. Die Spaltung durch stöchiometrische Mengen Triarylammoniumyl-hexachloroantimonate oder mit Hilfe der indirekten elektrochemischen Methode unter Verwendung katalytischer Mengen an Triarylamin in Verbindung mit der elektrochemischen Erzeugung und Regeneration der Radikalkationen führt zu gleich guten Ausbeuten. Im Falle der 1,3-Dithiolane ist die Anwendung stöchiometrischer Mengen von Tris(4-bromphenyl)ammoniumyl-hexachloroantimonat sehr effektiv, während im Verlauf der indirekten elektrochemischen Umsetzung die Ablagerung polymerer Schwefelverbindungen auf der Elektrodenoberfläche durch Verwendung einer Durchflußzelle verhindert werden muß. In allen Fällen sind die Spaltbedingungen so mild, daß Hydroxyfunktionen und Doppelbindungen ohne Probleme toleriert werden.
    Notes: 1,3-Dithianes 2 can effectively be converted in to the parent carbonyl compounds 7 by a very mild oxidative procedure using tri-p-tolylammoniumyl (1a+.) or tris(4-bromophenyl)ammoniumyl (1b+.) as homogeneous electron transfer agents. The yields are equally good for the cleavage by stoichiometric amounts of the triarylammoniumyl hexachloroantimonates as well as for the indirect electrochemical procedure using catalytic amounts of the triarylamine together with electrochemical generation and regeneration of the cation radicals. In the case of 1,3-dithiolanes 3 the application of stoichiometric amounts of tris(4-bromophenyl)ammoniumyl hexachloroantimonate is very effective while during the indirect electrochemical procedure the deposition of polymeric sulfur compounds onto the electrode surface has to be prevented by the use of a flow-through cell. In all cases the conditions for the cleavage are so mild that hydroxy functions and double bonds are tolerated without problems.
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  • 98
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1695-1706 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Degradation of (PhP)5 by Cyanide: Formation, Structure, and Reactions of the Phenyl Cyanophosphide Ion1)Phenyl cyanophosphide PhPCN- is formed in the reactions of P(CN)2- with phenyllithium and of PhP(CN)2 with CN-, and it may best be prepared by nucleophilic degradation of (PhP)5 with ammonium or phosphonium cyanides. With sulfur it yields phenyl cyanodithiophosphinates 4, by alkylation alkyl(phenyl)cyanophosphanes 6 and by hydrolysis of the latter alkyl(phenyl)phosphine oxides 7. - The molecular structure of [Ph3PNPPh3]PhPCN (3c) as determined by X-ray analysis shows an almost planar anion with a 102° CPC angle. A long PC and short CN bond in the PCN group make PhPCN- appear as “cyanide complex of phenylphosphinidene”.
    Notes: Phenyl-cyanphosphid PhPCN- entsteht bei den Reaktionen von P(CN)2- mit Phenyllithium und von PhP(CN)2 mit CN-, sowie präparativ verwertbar durch nucleophilen Abbau von (PhP)5 mit Ammonium- oder Phosphoniumcyaniden. Mit Schwefel kann es weiter zu Phenyl-cyandithiophosphinat 4, durch Alkylieren zu Alkyl(phenyl)-cyanphosphanen 6 und durch deren Hydrolyse zu Alkyl(phenyl)phosphanoxiden 7 umgesetzt werden. - Die röntgenographisch bestimmte Struktur von [Ph3PNPPh3]PhPCN (3c) zeigt ein fast planares Anion mit einem CPC-Winkel von 102°. Der lange PC- und kurze CN-Abstand der PCN-Gruppe läßt PhPCN- als „Cyanidkomplex des Phenylphosphinidens“ erscheinen.
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  • 99
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1726-1747 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions with Diazoazoles, VII. 3H-Azolo-1,2,4-triazoles by 1,8- or 1,12-Electrocyclizations of 3H-Pyrazol-3-one- or 3H-Indazol-3-one (Diorganylmethylene)hydrazones, Respectively3H-Azolo-1,2,4-triazoles 3 are formed by cycloreactions 2b) of diazoazoles 1 with diazoalkanes 2 and with fluorene--N-, P-, S-ylides 4, respectively, (Method A) or by cyclizing dehydrogenation of diorganylmethanone (1H-azol-3-yl)hydrazones 7 (Method B). In both methods the anellation of the triazol system results from 1,8- or 1,12-electrocyclization of azol-3-one (diorganylmethylene)-hydrazones (azines) 9, as could be shown in the case of the 4-nitrophenyl compound 9dk. - Spectroscopic data (UV, 1H NMR, 13C NMR) of the 3H-azolo-1,2,4-triazoles 3 are discussed.
    Notes: 3H-Azolo-1,2,4-triazole 3 entstehen durch Cycloreaktion2b) von Diazoazolen 1 mit Diazoalkanen 2 bzw. mit Fluoren-N-, P-, S-Yliden 4 (Methode A) oder durch cyclisierende Dehydrierung von Diorganylmethanon-(1H-azol-3-yl)hydrazonen 7 (Methode B). Bei beiden Methoden erfolgt die Triazolanellierung durch 1,8- bzw. 1,12-Elektrocyclisierung von Azol-3-on-(diorganylmethylen)-hydrazonen (Azine) 9, wie im Fall der 4-Nitrophenylverbindung 9dk gezeigt werden konnte. - Spektroskopische Daten (UV, 1H-NMR, 13C-NMR) der 3H-Azolo-1,2,4-triazole 3 werden diskutiert.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 1707-1725 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaktionen des (Pentafluorsulfanyl)isocyanats und -isothiocyanatsDie Reinigung des (Pentafluorsulfanyl)isocyanats (1) wird durch die Isolierung von (Pentafluorsulfanyl)carbamoylfluorid erleichtert. (Pentafluorsulfanyl)isothiocyanat (2) ist aus Dichlor(pentafluorsulfanylimino)methan und Phosphorpentasulfid in siedendem Toluol leicht erhältlich. 1 und 2 reagieren mit Alkoholen zu den Urethanen 3a - e bzw. Thiourethan 4 und mit Thiolen zu den Thiolurethanen 5a, b bzw. Dithiourethan 6. Mit Aminen reagieren 1 und 2 zu den verschiedenen substituierten Harnstoffen 7, 8a - e, 10a - c bzw. Thioharnstoff 9. Von besonderem Interesse ist die Reaktion von 1 mit tertiären Aminen zu den zwitterionischen Derivaten 11a, b. N-(Pentafluorsulfanyl)imin-Derivate 12a - e, 13a, b, 14 werden aus 1 oder 2 mit Aldehyden und N,N-disubstituierten Amiden hergestellt. Die Reaktion von 1 mit Acetylaceton gibt das N-(Pentafluorsulfanyl)amid 16 der Diacetessigsäure, das in Lösung in der Ketoform und zwei Enolformen beobachtet wird. Mit Trimethyl-orthoformiat gibt 1 nicht nur das erwartete N-Methyl-N-(pentafluorsulfanyl)urethan 18, sondern auch das klassische Additionsprodukt 2,2,2-Trimethoxy-N-(pentafluorsulfanyl)acetamid (17).
    Notes: The purification of pentafluorosulfanyl isocyanate (1) is rendered less difficult by isolation of the intermediate (pentafluorosulfanyl)carbamoyl fluoride, while pentafluorosulfanyl isothiocyanate (2) can easily be prepared by the reaction of dichloro(pentafluorosulfanylimino)methane with phosphorus pentasulfide in boiling toluene. Both 1 and 2 react readily with alcohols to give urethanes 3a - e and thiourethane 4, respectively, and with thiols to give thiolurethanes 5a, b and dithiourethane 6. With amines 1 and 2 form a variety of substituted ureas 7, 8a - e, 10a - c, and thiourea 9. Of particular interest is the reaction of 1 with tertiary amines which yields zwitterionic derivatives 11a, b. N-(Pentafluorosulfanyl)imine derivatives 12a - e, 13a, b, 14 are prepared from the reactions of 1 or 2 with aldehydes and N,N-disubstituted amides. The reaction of 1 with acetylacetone gives the N-(pentafluorosulfanyl)amide of diacetoacetic acid (16), which in solution is observed in both the keto form and two distinct enol forms. With trimethyl orthoformate 1 gives not only the expected N-methyl-N-(pentafluorosulfanyl)urethane 18 but also the classical addition product 2,2,2-trimethoxy-N-(pentafluorosulfanyl)acetamide (17).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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