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  • 1
    Electronic Resource
    Electronic Resource
    Zur Photolyse des ZinksulfidsProfessor Robert Schwarz zum 60. Geburtstage gewidmet (1947)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 255 (1947), S. 45-64 
    Details
    ISSN: 0372-7874
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wird Über Versuche berichtet, die unternommen wurden, die Bedingungen zu studieren, die die Lichtempfindlichkeit des Zinksulfids beeinflussen.Es wird im einzelnen Folgendes festgestellt: 1 Die Belichtungstemperatur besitzt keinen wesentlichen Einfluß auf den Ablauf der Photolysereaktionen.2 Die Kristallstruktur ist entgegen der bisherigen Auffassung ohne wesentliche Bedeutung.3 Lichtempfindlichkeit und Korngrößenverteilung der Präparate gehen parallel, und es lassen sich aus einem Präparat durch Fraktionieren nach der Korngröße verschieden lichtempfindliche Fraktionen gewinnen. Es lassen sich weiterhin durch hydrothermale Synthese aus Zinksulfid reine Blenden herstellen, die dieselbe Lichtempfindlichkeit haben, wie hochgeglühte Präparate mit Wurtzitstruktur.Die Wirkung von Schwermetallzusätzen wird untersucht und auf Grund der von M. BODENSTEIN für die Silberhalogenide entwickelten Anschauungen diskutiert.Abschließend wird Über Versuche berichtet, die den Einfluß der Konzentrationsbedingungen bei der Fällung von reinem ZnS und von Lithopone zum Gegenstand haben.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19472550106
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  • 2
    Electronic Resource
    Electronic Resource
    Über das Schwefelmonoxyd. 4. Mitteilung. Die Oxydation des Schwefels (1934)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 220 (1934), S. 268-272 
    Details
    ISSN: 0863-1786
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Oxydation von Schwefel wird unter verschiedenen Bedingungen auf die Entstehung von Schwefelmonoxyd hin untersucht.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19342200307
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of (R)-Sulforaphane Using [cpru(R, R)-CHIRAPHOS)]+ as Chiral AuxiliaryEnantioselective organic syntheses using chiral transition metal complexes, part 3. For part 2 see ref. [1]. (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 713-716 
    Details
    ISSN: 0947-6539
    Keywords: asymmetric synthesis ; dioxiranes ; ruthenium ; sulforaphane ; sulfoxides ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new enantioselective (80% ee) synthesis of (R)-sulforaphane and its epimer (S)-sulforaphane is described, which makes use of the pseudo-tetrahedral complex fragment [CpRu-(CHIRAPHOS)]+ as a chiral auxiliary. Reaction of the chloride complexes [CpRu(L-L)Cl] [L-L = 1,-bis(diphenylphosphino)ethane (dppe), (2S,3S)-and (2R,3R)-bis(diphenylphosphino)-butane ((S,S)- and (R, R)-CHIRAPHOS, respectively)] with phthalimidobutyl methyl sulfide gives the thioether complexes [CpRu(L-L)(MeSC4H8NPhth)]PF6. Oxygen transfer from dimethyldioxirane (DMD) produces the corresponding sulfoxide complexes in high yield and high diastereoselectivity. Cleavage of the phthaloyl group with aqueous hydrazine and subsequent reaction with thiophosgene yields the sulforaphane complexes [CpRu(L-L)(MeS(O)C4H8NCS)]PF6. Treatment of these with sodium iodide finally liberates the sulforaphane without noticeable racemization.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030510
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  • 4
    Electronic Resource
    Electronic Resource
    Van der Waals model for filled rubbers with modified interfacial contacts (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 345-362 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It is shown how the global deformation mechanism in filler-loaded vulcanizates were modified by additional filler-to-matrix bonds. A quantitative description is given in terms of an extended van der Waals treatment including the formulation of a reduced mechanical equation of state. An interpretation of the Mullins softening is presented.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070350206
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  • 5
    Electronic Resource
    Electronic Resource
    Scale-down and optimization studies of the gluconic acid fermentation by Gluconobacter oxydans (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 27 (1985), S. 711-720 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: To simulate production-scale conditions of gluconic acid fermentation by Gluconobacter oxydans, different experimental setups are presented in this study. From the determination of the time constants of a production-scale reactor, it can be concluded that mixing and oxygen transfer are the rate-limiting mechanisms. This results in oxygen concentration gradients which were simulated in a one-compartment reactor in which the oxygen concentration was fluctuated by a fluctuated gassing with air and nitrogen. It could be concluded that only very long periods of absence of oxygen (ca. 180 s) results in lower specific oxygen uptake rates by Gluconobacter oxydans. From scale-down studies carried out in a two-compartment system to simulate a production-scale reactor more accurately, it could be concluded that not only the residence time in the aerated part of the system is important, but the liquid flow in between the different parts of the reactor is also an essential parameter. It could also be concluded that the microorganisms are not influenced negatively by the fluctuated oxygen concentrations with respect to their maximal oxidation capacity. The two-compartment system can also be used for optimization experiments in which the “aerated” compartment was gassed with pure oxygen. From these experiments it was concluded that also a short residence of the cells at high oxygen concentrations diminished the growth and product formation rates. These experiments show the necessity of the scale-down experiments if optimization is carried out. The two-compartment system presented in this study is a very attractive tool for reliable scale-down experiments.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260270521
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation of 1-Hydroxycyclopentanecarboxylic Acid Derivatives from a Chiral Equivalent of Glycolic Acid (1999)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1999 (1999), S. 477-483 
    Details
    ISSN: 1434-193X
    Keywords: Radical reactions ; Glycolic acid ; Asymmetric synthesis ; Annulation ; Selenium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -The stereoselective preparation of 1-hydroxycyclopentanecarboxylic acid derivatives is reported. The key reaction is either a radical cyclization or a radical annulation mediated by the transfer of a phenylseleno group. The radical precursors are easily synthesized by two consecutive enolate alkylations. Excellent stereochemical control for the quaternary C(1) stereogenic center has been achieved.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Atropisomeric Transition State Analogs (2000)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 2000 (2000), S. 1365-1372 
    Details
    ISSN: 1434-193X
    Keywords: Atropisomerism ; Transition states ; Enzyme inhibitors ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: -Transition state mimicry is one of the most powerful concepts in enzyme inhibitor design and has led to the development of catalytic antibodies. Transition state analogs are compounds with a fixed shape that resemble the geometry and charge distribution of the transition state of a given reaction. Stabilization of a transition state like conformation is most often achieved by incorporating a ring system into the analog. We show herein that atropisomerism can be used as a new principle for enforcing a transition state like conformation. Atropisomerism relates to the existence of stereoisomers of structurally constrained molecules due to a frozen rotation about a single bond, as for example in binaphthol. The 1-aminomethylnaphthalene derivative 1 exhibits atropisomerism due to a frozen rotation about the C(1)-C(methylene) single bond, which holds the dihedral angle θ[C(2)-C(1)-C(methylene)-N] close to 90°. Compound 1 mimics the transition state for hydride transfer between 1,4-dihydroquinolines 4 and acetone.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chiral Ruthenium-Sulfene Complexes - Synthesis and C-C Coupling Reactions (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 287-297 
    Details
    ISSN: 1434-1948
    Keywords: Enolates ; Nucleophilic additions ; Ruthenium ; S ligands ; Sulfenes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of the chiral racemic complex [CpRu(mppe)(SO2)]PF6 (1, mppe = Me2PC2H4PPh2) with diazomethane or -ethane gave the sulfene complexes [CpRu(mppe)(RHC/SO2)]PF6 (R = H, 2a; R = Me, 2b). Treatment of 2a with prochiral enamines or deprotonated β-oxo esters yielded C-C coupling products with 32-60% de. An analog of 2a, [NmcpRu(mppe)(H2C/SO2)]PF6 (8, Nmcp = neomenthylcyclopentadienyl) was prepared in a four-step synthesis starting from LiNmcp and [RuCl2(PPh3)3]. Repeated crystallization of the intermediate [NmcpRu(mppe)Cl] (6) provided diastereomerically pure 6′ which added methylene stereospecifically to give diastereomerically pure 8′. Compound 8 turned out to be much less reactive towards nucleophiles than 2a, but still added deprotonated ethyl 2-methyl-3-oxobutanoate with 44% de. The chiral, enantiomerically pure sulfur dioxide complex [CpRu(chir)(SO2)]PF6 [10, chir = (S,S)-Ph2PCHMeCHMePPh2] was synthesized from [CpRu(chir)Cl] and SO2 and was characterized by X-ray crystallography. Reaction of 10 with diazomethane gave the enantiomerically pure sulfene complex [CpRu(chir)(H2C/SO2)]PF6 (11). Addition reactions of 11 with N-(1-cyclopentenyl)morpholine, as well as with various enolates derived from β-oxo esters or 1,3-diesters proceeded with high yields and 20-90% de. The structure of a diastereomerically pure addition product, [CpRu(chir)(SO2CH2C(Me){C(O)Me}{C(O)OtBu}] (13d′), was determined crystallographically and was shown to have (R) configuration at the quaternary carbon atom. After alkylation of one of the S/O functions, the sulfinate ligand was cleaved from the metal center by ligand substitution with acetonitrile, and the resulting acetonitrile complex 15 was converted back into 10 by treatment with SO2.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    X-ray Structures of a Phenanthroline-Strapped Porphyrin and Its Dihydrated Zinc(II) Complex: Convergent Distal Hydrogen Bonds and “CH···O” Interactions (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1175-1179 
    Details
    ISSN: 1434-1948
    Keywords: Hydrogen bonds ; Inclusion compounds ; Solid-state structures ; Porphyrinoids ; Zinc ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The X-ray structure of a phenanthroline-(phen-)strapped 1,10-diphenylporphyrin 1 has been resolved. From the structure obtained, it is apparent that in spite of the rigidity of the strap the porphyrin ring is only slightly distorted, and that the substituents on the phen moiety define what would seem to be a hydrophobic pocket. Metallation of the free base 1 with zinc(II) acetate yields a metallic complex (1)Zn with a free axial coordination site. Crystallization of the zinc complex in the presence of a hindered base (N-methylimidazole, denoted N-MeIm) in organic solvents affords single crystals of a porphyrinatozinc(II) species, in which two water molecules are surprisingly present in the encumbered (distal) pocket of the phen site. One water molecule is axially bound to the zinc(II) ion, while the other is doubly hydrogen-bonded, as an H-bond donor to the phenanthroline and as an H-bond acceptor to the axial water ligand.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chiral Rhenium Complexes of Functionalized Thioaldehydes (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1435-1443 
    Details
    ISSN: 1434-1948
    Keywords: Captopril ; Cysteine ; Rhenium ; S ligands ; Thioaldehydes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral racemic rhenium thioaldehyde complexes [CpRe(NO)(PPh3)(η2-S=CHR)]PF6 (2a-g) bearing functionalized aliphatic groups R [R = CH2Ph (a), COOEt (b), CH2COOMe (c), CH2C(O)NHCH2Ph (d), (R)-CH(NC8H4O2)COOMe (e), (S,S)-CH(Me)C(O)NC4H7COOMe (f), C4H3O (g)] have been obtained by hydride abstraction from the corresponding thiolate complexes [CpRe(NO)(PPh3)(SCH2R)] (1a-g). With the exception of 2b, only single stereoisomers with like configurations at rhenium and the thioaldehyde carbon atom were obtained. In some cases, the corresponding sulfinate complexes [CpRe(NO)(PPh3)(SO2CH2R)] (3d-f) were formed as by-products. The analogous toluenesulfinate complex [CpRe(NO)(PPh3){SO2(4-C6H4CH3)}] (3a) has been prepared from [CpRe(NO)(PPh3)(THF)]BF4 (8), and the structure of 3e has been determined by X-ray crystallography. The use of phosphorus ligands other than PPh3 was briefly explored with the synthesis of [CpRe(NO)(PR′3)(η2-S=CHR)]PF6 (5a-d) [R′ = OPh, R = Ph (a), 4-C6H4Cl (b), R′ = iPr, R = Ph (c), H (d)]. Nucleophilic addition of NaSMe to [CpRe(NO)(PPh3){η2-S=CH(4-C6H4OMe)}]PF6 (5e) gave the dithioacetal complex [CpRe(NO)(PPh3){SCH(SMe)(4-C6H4OMe)}] (9) in high yield and with low diastereoselectivity. Diels-Alder additions of 5a, e with 2,3-dimethylbutadiene and 2,3-dimethoxy-butadiene gave complexes of cyclic thioethers (10a-c). From the relative rates of reaction (5a 〉〉 5e) and the low diastereoselectivity, it was concluded that the cycloadditions as well as the nucleophilic addition proceed via the linkage isomers [CpRe(NO)(PR′3)(η1-S=CHR)]PF6.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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