ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Chemistry  (35)
  • Life and Medical Sciences
  • 1995-1999  (35)
  • 1925-1929
  • 1999  (35)
Collection
Keywords
Publisher
Years
  • 1995-1999  (35)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    Nucleophilic Aromatic Substitution of Hydrogen in the Reaction of tert-Alkylamines with Nitrosobenzenes - Synthesis and NMR Study of N-(tert-Alkyl)-ortho-nitrosoanilines (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 29-35 
    Details
    ISSN: 1434-193X
    Keywords: Nitrosobenzenes ; ortho-Nitrosoanilines ; 2-Nitroso-1,3-phenylenediamines ; Nucleophilic aromatic substitution ; Oxidative nucleophilic substitution of hydrogen ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -The reaction of primary amines bearing tertiary alkyl groups (e.g. R-NH2; R = tBu, 1-adamantyl) with nitrosobenzenes has been found to proceed by oxidative nucleophilic aromatic substitution of hydrogen, thereby affording N-(tert-alkyl)-ortho- and -para-nitrosoanilines. The replacement of hydrogen proceeds more rapidly than the replacement of ortho- or para-nitro or -bromo substituents. With p-nitronitrosobenzene, both ortho-hydrogen atoms are substituted to afford N,N′-di(tert-alkyl)-4-nitro-2-nitroso-1,3-phenylenediamines 8a,b. The addition of oxidizing agents (e.g. MnO2) increases the yield of products. 1H-, 13C-, 14N- and 15N-NMR studies have confirmed the structures of the compounds under investigation. In ortho-nitrosoanilines, the rotamer with the nitroso group syn to the amino group is favored.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    A Dimeric Tetranuclear Copper(II) Compound Assembled through Pentacoordinating Carbonate Anions (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 505-507 
    Details
    ISSN: 1434-1948
    Keywords: Macrocycle ; Pyrazole ; N-Heterocycle ; Carbonate ; Copper ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 22-membered macrocycle, spanning four endocyclic pyrazole groups, viz. 1,4,9,14,17,22,27,28,29,30-decaaza-5,13,18,26-tetramethylpentacyclo[24.2.1.14,7.111,14.117,20]triacontane-5,7(28),11(29),12,18,20(30),24(27),25-octaene (22Pz), rendered the tetranuclear compound [Cu4(22Pz)2(CO3)2(MeOH)2](ClO4)4(MeOH)4. The copper(II) ions are in distorted octahedral N3O3 environments. All four pyrazole groups of each macrocycle participate in the coordination of the copper(II) ions. The cationic part of this compound is in fact a dimer of two macrocyclic ligands, each containing two copper(II) ions bridged by two carbonate ions in the highly unusual pentacoordinating fashion.Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2005/1999/98332_s.pdf or from the author.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    3-Trifloxy-3-trifluoromethylpropeniminium Triflate: Reaction with Aromatic Amines - An Efficient Synthesis of 2-Trifluoromethylquinolines (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 937-941 
    Details
    ISSN: 1434-193X
    Keywords: Iminium salts ; Triflic anhydride ; Arylamines ; 2-Trifluoromethyl quinolines ; 3-Trifluoromethyl-cinnamaldehydes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -The reaction of iminium triflates 2 and 7 with various aromatic amines were investigated. The 2-Rf-substituted quinolines 3 and 8 were prepared in excellent yields by the reaction of 2 and 7, respectively, with substituted anilines. The reactions of 2 and 7 with diarylamines proceeds, suprisingly, to afford the corresponding 3-Rf-substituted cinnamaldehydes 4 and 9.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Photochemical pKa-Modulation and Gated Photochromic Properties of a Novel Diarylethene Switch (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 2359-2366 
    Details
    ISSN: 1434-193X
    Keywords: Photochromism ; Diarylethenes ; Molecular devices ; Proton switches ; Merocyanines ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The unsymmetrical dithienylethene photochrome 1a exhibits proton-gated photochromic properties as well as novel chemical reactivity. The dimethoxylated derivative 9a represents a light-triggered proton switch whose dissociation constant is increased by a factor of 16 upon photochemical cyclization to 9b. Such compounds are of potential interest for multiplexing photochemical systems.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 5
    Electronic Resource
    Electronic Resource
    Synthesis and 1H-, 15N-, 31P-, 183W-Multinuclear Magnetic Resonance Study of the Cyclotriphosphazenes [N3P3(dobp)2(OC5H4N-4)2] and [N3P3(dobp)(OC5H4N-4)4] and Their W(CO)5 Complexes (dobp = 2,2′-dioxybiphenyl) (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1015-1020 
    Details
    ISSN: 1434-1948
    Keywords: Cyclotriphosphazenes ; Oxypyridine ; Carbonyltungsten compounds ; NMR spectroscopy ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of [N3P3(dobp)2Cl2] and [N3P3(dobp)Cl4] with a mixture of HOC5H4N-4 and K2CO3 in acetone give the cyclotriphosphazenes [N3P3(dobp)2(OC5H4N-4)2] and [N3P3(dobp)(OC5H4N-4)4], respectively. These compounds react with [W(MeOH)(CO)5] in methanol to give mixtures of the polymetallic complexes [N3P3(dobp)2(OC5H4N-4)2{W(CO)5}x] (x = 1, 2) and [N3P3(dobp)(OC5H4N-4)4{W(CO)5}x] (x = 1-4), which are unstable in solution, slowly undergoing loss of the pentacarbonyl moiety. A complete characterization by multinuclear 1H, 15N, 31P, 183W magnetic resonance has revealed that the complexation of the N atom of one 4-oxypyridine ligand by the W(CO)5 fragment has a measurable effect on other parts of the phosphazene molecule very far away from the coordination site. The changes observed in δ183W have been used to identify the components in mixtures of compounds incorporating different numbers of tungsten atoms in the molecule. The characterization of less sensitive nuclei has been accomplished by means of indirect detection methods.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Crystallographic and Spectroscopic Characterization of Tetrakis(μ-N,N′-diarylformamidinato)dichlorodirhenium(III,III) Compounds (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 2095-2103 
    Details
    ISSN: 1434-1948
    Keywords: Metal-metal bonds ; Rhenium ; Formamidinate ; UV/Vis spectroscopy ; Electrochemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Through a variation in the aryl substituents of the formamidinate ligand, a variety of dirhenium compounds has been synthesized with [XArNC(H)NArX]- where Ar is a substituted C6H5 or C6H4 aryl ring and × is p-MeO (1), H (3), m-MeO (4), p-Cl (5), m-Cl (6), m-CF3 (7), p-CF3 (8), 3,4-Cl2 (9), and 3,5-Cl2 (10a, 10b). UV/Vis and NMR spectroscopy and electrochemical data for 1and 3-10 have been obtained. X-ray crystallographic analysis of Re2Cl2(μ-form)4 with four different diarylformamidinate ligands and one analog with two different interstitial solvents are presented; Re2Cl2[(p-MeOC6H4)NCHN(p-MeOC6H4)]4 (1), Re2Cl2[(m-MeOC6H4)-NCHN(m-MeOC6H4)]4 · 2 CH2Cl2 (4), Re2Cl2[(3,4-Cl2C6H3)NCHN(3,4-Cl2C6H3)]4 · 2 CH2Cl2 (9), Re2Cl2[(3,5-Cl2C6H3)NCHN(3,5-Cl2C6H3)]4 · 4 CH2Cl2 (10a), and Re2Cl2[(3,5-Cl2C6H3)NCHN(3,5-Cl2C6H3)]4 · OC4H8 (10b).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 7
    Electronic Resource
    Electronic Resource
    Dirhodium Tetra(N-arylsulfonylprolinates) as Chiral Catalysts For Asymmetric Transformations of Vinyl- and Aryldiazoacetates (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 2459-2469 
    Details
    ISSN: 1434-193X
    Keywords: Asymmetric synthesis ; C-H activation ; Carbenoids ; Cycloaddition ; Rhodium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Rhodium(II( prolinates are superb catalysts for asymmetric transformations of vinyldiazoacetates and phenyldiazoacetates. The most well-developed transformation is the [3 + 4] annulation between vinyldiazoacetates and dienes which is a very general method for the stereoselective synthesis of highly functionalized seven-membered rings. Recent studies have led to a general method for asymmetric intermolecular C-H activation which displays promising regio- and diastereocontrol in addition to the enantiocontrol.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 8
    Electronic Resource
    Electronic Resource
    Synthesis, Structure, and Stereodynamics of an N,N-Chiral “Proton Sponge” (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 2501-2510 
    Details
    ISSN: 1434-193X
    Keywords: Proton Sponges ; N-Chirality ; Isotopic labelling ; Stereodynamics ; NMR ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,8-Bis(N-benzyl-N-methylamino)naphthalene (2) and its hydrogen iodide salt [2H]+[I]- were synthesised from 1,8-diaminonaphthalene. The thermodynamic diastereomer ratios of (2) and [2H]+ in [D7]DMF are 73.4:26.6 and 89.7:10.3 respectively at 293 K. The solid state structures of the major dl-(RNRNSNSN) diastereomers were determined by single crystal X-ray diffraction. The minor diastereomers were shown to be the meso-(RNSN) forms by performing 1H-NMR NOE studies on isotopically desymmetrized 1-(N-benzyl-N-[13C]-methylamino)-8-(N′-benzyl-N′-methylamino)naphthalene [13C]-2 and the salt [13C]-[2H]+. In [D7]DMF at 298 K, the meso form of the free base 2 is 0.6 (± 0.07) kcal·mol-1 less stable than the dl form (ΔH° = -0.64 (±0.03) kcal·mol-1; ΔS° = -0.18 (±0.13) cal·K-1mol-1) and the activation barriers for interconversion are ca. 14.2 (±0.4) and 14.8 (±0.4) kcal·mol-1 respectively. The effect of solvent polarity on the entropy and enthalpy change on approach to the transition state was studied. An approximate correlation with the solvent dielectric constant was found for both ΔH# and ΔS# and this may be ascribed to the development of a net dipole in the transition state due to substantially different hybridisation and geometry at the two nitrogen centres.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 9
    Electronic Resource
    Electronic Resource
    N-Substituted 1-Aminoindoles from Electrogenerated N-Substituted 2-(ortho-Nitrosophenyl)ethylamines (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 419-430 
    Details
    ISSN: 1434-193X
    Keywords: Electrochemistry ; Electrosynthesis ; Nitrosobenzenes ; Nitrogen heterocycles ; 1-Aminoindoles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -An electrochemical methodology offering efficient access to N-alkyl- and N-aryl-substituted 1-aminoindoles has been developed. N-Substituted 2-(ortho-nitrosophenyl)ethylamines, electrogenerated in a “redox” flow cell, undergo intramolecular cyclization to hydrocinnoline-type intermediates. Under slightly basic conditions, these undergo spontaneous ring-contraction to produce the N-substituted heterocycles in good yields. The reactions have been studied in slightly acidic and slightly basic aqueous alcoholic media.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 10
    Electronic Resource
    Electronic Resource
    Diastereoselective Intramolecular meta Photocycloaddition of Side-Chain-Substituted 5-(2-Methoxyphenyl)pent-1-enes (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 463-470 
    Details
    ISSN: 1434-193X
    Keywords: meta Photocycloaddition ; Photochemistry ; Steric hindrance ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -Irradiation of a series of 5-(2-methoxyphenyl)pent-1-enes substituted with a hydroxy or trimethylsilyloxy group at the α-, β-, or γ-position of the side-chain yields in all cases meta photocycloadducts, in which the configuration at the substituted carbon atom is mainly endo. This indicates that the diastereoselectivity originates from minimization of steric interactions between the side-chain substituent and the ortho-methoxy group at the arene unit. Hydrogen bonding does not seem to be involved. The introduction of the side-chain substituents also influences the regioselectivity of the addition: The linear to angular adduct ratios are significantly increased compared to the case of the parent compound.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...