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  • Organic Chemistry  (7)
  • SWISS-2DPAGE  (4)
  • Wiley-Blackwell  (11)
  • 2000-2004
  • 1995-1999  (7)
  • 1985-1989  (4)
  • 1
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nature and Stability of Some Metallic Complexes of Dinucleating Cryptands in Solution. I. A Polyazapolyoxa Cylindrical Macrotricycle and its Monocyclic SubunitpH-metry and UV spectrophotometry were used to study the complexing properties of the cylindrical macrotricycle, 1,7,13,19-tetraaza-4,16-dioxa-10,22,27,32-tetraoxatricyclo[17.5.5.5]tetratriacontane (1) and of its constitutive monocyclic subunit, 1,7-diaza-4,10-dioxacyclododecane (2) with some transition and heavy metal cations (Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+, Ag+), in aqueous medium 0.1M Et4NClO4, at 25°. The protonation constants of the ligands as well as the nature and the stabilities of the complexes formed in the pH-regions studied were determined. The tricycle 1 only formed dinuclear M2L complexes with Cu2+, Zn2+, and Ag+, accompanied in the latter case by a protonated mononuclear MLH species, and with Cu2+ and Zn2+ at high pH-values by dinuclear hydroxo complexes. Only mononuclear complexes were evidenced with the other cations, ML being accompanied either by protonated or hydroxy mononuclear species. The mononuclear complexes of 1, when they existed, were more stable than the corresponding complexes of 2, except for cobalt which formed complexes of comparable stability with both ligands. In the other cases (Cd2+, Pb2+, Ag+), the stability differences between the complexes of 1 and 2 increased with the size of the cation.
    Additional Material: 3 Ill.
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  • 2
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hydroxo complex (Bu4N)2[Ni2(C6F5)4(μ-OH)2]reacts with 2,3,4,5,6-pentafluoro benzenamine (C6F5-NH2), 1,3-diaryltriaz-1-enes (ArNH—N=N—Ar, Ar = Ph, 4-MeC6H4, 4-MeOC6H4), 7-aza-1H-indole (= 1H-pyrrolo[2.3-b]pyridine; Hazind), N-phenylpyridin-2-amine(pyNHPh), and N-phenylpyridine-2-carboxamide (py-CONHPh) at room temperature in acetone to give the binuclear complexes (Bu4N)2[Ni2(C6F5)4(μ-C6F5NH)2] (1) and (Bu4N)2[{Ni(C6F5)2} 2(μ-OH)(μ-azind)] (2) and the mononuclear complexes Bu4N[Ni(C6F5)2(ArN3Ar)] (3-5), Bu4N[Ni(C6F5)2(pyNPh)] (6), and Bu4N[Ni(C6F5)2(pyCONPh)] (7). The hydroxo.complex (Bu4N)2[{Ni(C6F5)2-(μ-OH)}2] promotes the nucleophilic addition of water to pyridine-2-carbonitrile, 2-aminoacetonitrile, and 2-(dimethylamino)acetonitrile, and complexes 8-10 containing pyridine-2-carboxamidato, 2-aminoacetamidato and 2-(dimethylamino)acetamidato ligands are formed. Analytical (C, H, N) and spectroscopic (IR, 1H and 19F-NMR, and FAB-MS) data were used for structural assignments. A single-crystal X-ray diffraction study of (Bu4N)2[{Ni(C6F5)2}2(μ-OH)(μ-azind)] (2) established the binuclear nature of the anion; the two Ni-atoms are bridged by an OH group and a 7-aza-7H-indol-7-yl group, but the central Ni—O—Ni—N—C—N ring is not planar, the dihedral angle between the Ni—O—Ni and Ni—N—C—N—Ni planes being 84.4°.
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 68 (1985), S. 840-845 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nature and Stability of Some Metallic Complexes of Dinucleating Cryptands in Solution III. The Monocycle [22]-Py2N4The nature and stability of complexes formed by a new 22-membered monocycle L = [22]-Py2N4 with the cations Mn+ = Cu2+, Co2+, Ni2+, Zn2+, Cd2+, Pb2+, and Ag+ have been determined in aqueous solutions (0.01M NaClO4, 25°) by pH-metry and also, for the copper system, by UV-absorption spectrophotometry. The stepwise protonation constants of the four amine functions of L were 9.1, 8.3, 7.1 and 3.7 logarithms units, respectively. No evidence was found for the protonation of the two pyridine nitrogen atoms. Mononuclear complexes MLn+ were identified in all systems investigated, but the dinuclear species M2L2n+ were only found with Cu2+ and Ag+. The logarithms of the overall stability constants for the copper and silver complexes are CuL2+, 12.9; Cu2L4+, 18.6; Agl+, 6.3; Ag2L2+, 10.9, respectively. Mononuclear hydroxy species MLOH(n-1)+ were identified in all systems except those of copper and silver. No dinuclear hydroxy complexes were detected. The complexing properties of L are compared to those of the large and less rigid bis-dien.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 7 (1995), S. 248-256 
    ISSN: 0899-0042
    Keywords: chiral discrimination ; chiral stationary phase ; network polymer ; DATD ; hydrogen bonding ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A strategy based on the use of homo bi- and multifunctional building blocks for the synthesis of a new class of network-polymeric chiral stationary phases has been evaluated. The key steps comprise acylation of N,N′-diallyl-L-tartardiamide (DATD) and reaction with a multifunctional hydrosilane, yielding a network polymer incorporating the bifunctional C2-symmetric chiral selector. Covalent bonding to a functionalized silica takes place during the latter process. Many of these chiral sorbents show interesting enantioselective properties toward a wide variety of racemic solutes under normal-phase (hexane-based) conditions. The retention is mainly caused by the hydrogen-bonding ability of the analyte, which is regulated by mobile phase additives like alcohol or ether cosolvents. The most interesting chiral stationary phases, in terms of broad enantioselectivity, were obtained from O,O′-diaryol-DATD-derivatives, particularly those containing the 3,5-dimethylbenzoyl and the 4-(tert-butyl)benzoyl moieties. Since high column efficiencies can be obtained with these chiral sorbents, an α-value of ca. 1.2 is usually sufficient to produce baseline separation. A large number of neutral as well as acidic or basic drug racemates are resolved without derivatization. © 1995 Wiley-Liss, Inc.
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  • 5
    ISSN: 0947-3440
    Keywords: Indazolols ; Indazolinones ; Indoxyls ; Cytostatic agents ; HeLa cells ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The remarkable cytostatic activity of 1-substituted indazolols 2a,b, condensed indazolinones 4a-c and indoxyl derivatives 5a, b against HeLa cells is reported. Three different approaches to the synthesis of indazolophthalazinone 4a, representing alternatives to those previously reported, were studied. Several compounds related to the mentioned indazolols and indazolinones were obtained and their cytostatic activity against HeLa cells was tested. Among them we can mention the tetracyclic SO2 analogue 14 and the condensed pyridine derivative 18, the tricyclic pyrazolophthalazinone 22 and the bicyclic pyrazolodiazepinone 25, which were prepared by taking advantage of the reactivity of heterocyclic spiro aminimides.
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  • 6
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heteroaromatische nucleophile Substitutionsreaktionen durch Phasen-Transfer-Katalyse- Synthese von neuen Alkoxypyridazin-3(2H)-onenDie Synthese von einigen 4- und 5-alkoxysubstituierten Pyridazin-3(2H)-onen mit hypotensiver und β-blockierender Wirkung durch Phasen-Transfer-Katalyse aus Halogenpyridazin-3(2H)-onen wird beschrieben. Der nucleophile Austausch verläuft recht glatt in der 5-Stellung aber viel langsamer in der 4-Stellung. Im Falle von 4,5-Dihalogenpyridazin-3(2H)-onen ergibt die Phasen-Transfer-Katalyse eine hohe Regioselektivität für die Substitution in 5-Stellung.
    Notes: The synthesis of several 4- and 5-alkoxy-substituted pyridazin-3(2H)-ones with hypotensive and β-blocking activities by phase-transfer catalysis (PTC) starting from halopyridazin-3(2H)-ones is described. The nucleophilic displacement reaction proceeds easily at the 5-position and remarkably slower at the 4-position. In the case of 4,5-dihalopyridazin-3(2H)-ones the PTC methods provide a high regioselectivity towards substitution in 5-position.
    Additional Material: 2 Tab.
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  • 7
    ISSN: 0170-2041
    Keywords: H1-Antihistaminic ; Piperazines ; Phase-transfer catalysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Potentielle H1-Antihistaminica: Synthese von 4-[(2,3-Dihydro-2-oxo-1H-benzimidazol-1-yl)alkoxycarbonyl]-1-(diphenylmethyl)piperazinen durch selektive Phasen-Transfer-katalysierte Monoalkoxycarbonylierung von α,ω-DichloralkanenDie Synthese einer Reihe von neuen 4-[(2,3-Dihydro-2-oxo-1H-benzimidazol-1-yl)alkoxycarbonyl]-1-(diphenylmethyl)piperazinen 2 durch Phasen-Transfer-katalysierte Monoalkoxycarbonylierung von α,ω-Dichloralkanen wird beschrieben. Die Piperazine 2 ähneln Oxatomid1) (1) und sind potentielle H1-Antihistaminica. Ferner wurde eine Untersuchung zur regioselektiven Synthese von substituierten 1,3-Dihydro-1-isopropenyl-2H-benzimidazol-2-onen (5) durchgeführt.
    Notes: The synthesis of a series of new 4-[(2,3-Dihydro-2-oxo-1H-benzimidazol-1-yl)alkoxycarbonyl]-1-(diphenylmethyl)piperazines 2 by phase-transfer catalysed monoalkoxycarbonylation of α,ω-dichloroalkanes is described. Compounds 2 are related to oxatomide1) (1) and are potential histamine-H1 antagonists. A study on the regioselective preparation of substituted 1,3-dihydro-1-isopropenyl-2H-benzimidazol-2-ones (5) was also carried out.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 16 (1995), S. 1131-1151 
    ISSN: 0173-0835
    Keywords: SWISS-2DPAGE ; Two-dimensional gel electrophoresis ; Protein database ; Protein mapping ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Several two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) databases have been established and updated for more than 15 years. Only recently have developments of computer networks and high-speed transfer protocols provided the required tools for sharing comprehensive and hypermedia 2-D PAGE databases. This publication describes the SWISS-2DPAGE database structure. Proteins present in samples of human tissue, cells, cell lines and body fluids are assembled and described in an accessible uniform format. SWISS-2DPAGE can be freely accessed through the World-Wide Web (WWW) network on the ExPASy molecular biology server.
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  • 9
    ISSN: 0173-0835
    Keywords: Yeast ; SWISS-2DPAGE ; Two-dimensional polyacrylamide gel electrophoresis ; Protein database ; Protein mapping ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The systematic sequencing of the yeast genome will soon be completed. A new challenge has been launched by the EUROFAN (European Functional Analysis) project whose goal is to elucidate the physiological and biochemical function of newly discovered open reading frames (ORF) from yeast. One of the approaches is to use protein-based technologies such as two-dimensional gel eletrophoresis and protein identification in order to establish a yeast reference map. Modified protein patterns can be compared to the reference map which hopefully will help identify changes related, for example, to growth processes or developmental events. This paper describes the yeast SWISS-2DPAGE database in which charge separation was obtained using immobilized pH gradient (IPG). Proteins identified by gel comparison, amino acid composition analysis and/or microsequencing are recorded and described in an accessible uniform format. We have identified more than one hundred polypeptides, several of which were newly mapped. In addition, the yeast SWISS-2DPAGE database can be freely accessed through the World Wide Web (WWW) network on the ExPASy molecular biology server.
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  • 10
    ISSN: 0173-0835
    Keywords: SWISS-2DPAGE ; Two-dimensional polyacryamide gel electrophoresis ; Protein database ; World Wide Web ; Federated data-base ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: While a two-dimensional electrophoresis (2-DE) database is a relatively old concept, in recent years it generated renewed interest within the 2-DE community due to two main factors: (i) The high reproducibility of the current 2-DE method allows 2-DE images to be exchanged and compared between laboratories. (ii) The recent development of faster and more powerful techniques for protein identification such as microsequencing, matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) and amino acid composition makes the production of reference protein maps and 2-DE databases cost- and time-effective. Additionally, the Internet network's current increase in popularity, combined with the rapid growth of Internet-connected laboratories, provides a straightforward means of publishing and sharing 2-DE data. While a small number of laboratories have already successfully published their data over the net, the increasing number of 2-DE database servers that are currently being set up will sooner or later require some kind of standardization. Unfortunately, standardization can be a long and cumbersome process inevitably leading to undesirable compromises. A federated database offers a simple and efficient way to publish and share 2-DE data without the need for standardization. Taking advantage of Internet protocols such as World Wide Web, they allow each laboratory to maintain their own database and to interconnect it with other similar databases through the use of active cross-references. This paper first presents guidelines for building a federated 2-DE database that may easily be followed by most laboratories. It then briefly reviews the state-of-the-art in networked 2-DE databases, and finally describes the SWISS-2DPAGE database which fully implements the concept of a federated 2-DE database.
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