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  • 1
    Electronic Resource
    Electronic Resource
    Spectrophotometric determination of picein and p-hydroxyacetophenone in needles of Picea abies with 2,4-dinitrophenylhydrazine (1974)
    s.l. : American Chemical Society
    Analytical chemistry 46 (1974), S. 789-791 
    Details
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ac60342a057
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  • 2
    Electronic Resource
    Electronic Resource
    Vanadium(II)- and Niobium(III)-Induced, Diastereoselective Pinacol Coupling of Peptide Aldehydes to Give a C2-Symmetrical HIV Protease InhibitorDedicated to Professor Richard Neidlein on the occasion of his 65th birthday (1996)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 2 (1996), S. 307-315 
    Details
    ISSN: 0947-6539
    Keywords: enzyme inhibitors ; niobium complexes ; peptide aldehydes ; pinacol coupling ; vanadium complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Peptide aldehydes 15 a-c are prepared without epimerization from enantiomerically pure (S)-α-amino acids (Scheme 3). Reductive pinacol homocoupling of 15 a-c, induced by vanadium complex 11 or niobium complex 16 in refluxing THF, yields C2-symmetrical (S,R,R,S)-configurated 6a, 6b and 2, respectively, with moderate to high stereoselectivity (Scheme 4). In a novel protocol for the preparation and utilization of THF solutions of 11, the isolation of air-sensitive intermediates can be avoided and the potent HIV protease inhibitor 2 prepared in enantio- and diastereomerically pure form on a kilogram scale without chromatographic purification. The (S,R,R,S) selectivity of the pinacol homocouplings is confirmed by means of an independent, stereochemically unequivocal synthesis of 6 a and 2 from D-mannitol 4 (Scheme 1).
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19960020312
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  • 3
    Electronic Resource
    Electronic Resource
    Role of leukotrienes in acute gastric lesions induced by ethanol, taurocholate, aspirin, platelet-activating factor and stress in rats (1988)
    Springer
    Digestive diseases and sciences 33 (1988), S. 806-813 
    Details
    ISSN: 1573-2568
    Keywords: leukotrienes ; prostaglandins ; gastric ulcerations ; platelet-activating factor ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study was designed to determine the role of leukotriene C4 (LTC4) in the formation of acute gastric lesions induced by 100% ethanol, acidified taurocholate (TC), acidified aspirin (ASA), platelet-activating factor (PAF), and water-immersion and restraint stress. Exogenous LTC4 alone administered in gradually increasing doses (5–20μg/kg/hr) caused only mild hemorrhagic lesions in the gastric mucosa but when combined with 100% ethanol, acidified TC, acidified ASA, or stress, it increased significantly the mean lesion area and lesion number as compared to those produced by these ulcerogens alone. FPL 55712, a LTC4 antagonist, given orally (2.5–10 mg/kg) reduced dose-dependently the extent of gastric lesions in all experimental models used and completely prevented the deleterious effects of exogenous LTC4 on gastric mucosa. PAF augmented the mucosal lesions induced by 100% ethanol, and this was also reduced by the pretreatment with FPL 55712. FPL 55712-induced gastroprotection against various ulcerogens was reversed, in part, by indomethacin, indicating that it could be attributed not only to the LTC4 antagonism but also to increased biosynthesis of PGs. This study provides evidence that LTC4 is involved in the formation of acute gastric damage and the antagonism of LTC4 may protect the mucosa against various ulcerogens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01550967
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  • 4
    Electronic Resource
    Electronic Resource
    Nonactinsäure-Diastereomere und 2-Desmethyl-nonactinsäure-Epimere (1971)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 21-30 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diastereomers of Nonactin Acid and Epimers of 2-Desmethylnonactin AcidNonactin acid 8a was prepared in only four reaction steps starting from the furan 3a. - In an attempt to prepare nonactin acid by intramolecular cyclisation of 13, the tetrahydropyran 15 was obtained in addition to the desired tetrahydrofuran 14. Treatment of 14 + 15 with sodium cyanide under the conditions of the Kolbe reaction led to the formation of the isomeric acids 16 + 17.
    Notes: Ausgehend von dem Furan 3a gelangt man in vier Reaktionsschritten zur Nonactinsäure 8a, einem 2.5-disubstituierten Tetrahydrofuran. - Beim Versuch der Darstellung von Nonactinsäure durch intramolekulare Cyclisierung von 13 entstand neben dem gewünschten Tetrahydrofuran 14 durch Ringerweiterung auch das Tetrahydropyran 15. Die Umwandlung von 14 + 15 mit Natriumcyanid nach Kolbe führte zu den stellungsisomeren Säuren 16 + 17.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19711040105
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  • 5
    Electronic Resource
    Electronic Resource
    Orthoamide, XX. Umsetzungen von Amidacetalen und Bis-dimethylamino-methoxy-methan (Aminalester) mit Benzaziden (1971)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 3794-3803 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Orthoamides, XX. Reactions of Amide Acetals and Bis(dimethylamino)-methoxymethane (Aminal Ester) with Benzoic AzidesUpon thermal reaction of amide acetals (1) with benzoic azides (2) only products are obtained arising from secondary reactions of the phenyl isocyanates formed intermediately from the azides. In the photochemical reaction, acyl hydrazines 15 may be isolated formed via acyl nitrene intermediates.
    Notes: Bei der thermischen Umsetzung von Amidacetalen (1) mit Benzaziden (2) werden lediglich die Folgeprodukte der intermediär aus den Aziden gebildeten Phenylisocyanate erhalten. Hingegen gelingt es bei der photochemischen Reaktion die Folgeprodukte intermediär gebildeter Acylnitrene, die Acylhydrazine 15, zu isolieren.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19711041209
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  • 6
    Electronic Resource
    Electronic Resource
    Eine neue Synthese für 1,2,3-Triazole (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 2758-2766 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A New Synthesis of 1,2,3-TriazolesA new method for the preparation of 1,2,3-triazoles (7) in good yield starting from vinyl-sulfonyl compounds 6 is reported. Compounds 6 are easily obtained by condensation of sulfonylmethyl derivatives 4 with aldehydes 5.
    Notes: Eine neue ergiebige Methode zur Herstellung von 1,2,3-Triazolen (7), ausgehend von den Vinylsulfonylverbindungen 6, wird beschrieben. Die Verbindungen 6 sind durch Kondensation der Sulfonylmethylverbindungen 4 mit den Aldehyden 5 leicht zugänglich.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731060903
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  • 7
    Electronic Resource
    Electronic Resource
    Synthese eines biologisch aktiven Analogons des Prostaglandins E2 (Racemat und reine Enantiomere) (1987)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1987 (1987), S. 321-326 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of a Biologically Active Analogue of Prostaglandin E2 (Racemate and Enantiomerically Pure Compounds)Transformation of 6-chloro-3-oxo-2-oxabicyclo[3.2.1]octane-8-carbaldehyde (6) by an eight-step synthesis leads to racemic (5Z,13E)-11,15-dihydroxy-16,16-dimethyl-9-oxo-18-oxa-5,13-prostadienoic acid (1) (dimoxaprost). The synthesis starts with the introduction of the ω-side chain of 1 into 6 by Horner-Emmons-Wittig reaction with the phosphonate 7. Ring cleavage and rearrangement of 8 affords enone 9a with unprotected hydroxyl group. By stereoselective reduction of 9a, diol 11a is obtained. Subsequently, 11a is converted in five steps through the “Corey synthesis” into 1. The 5-ketoprostacyclin 17 is isolated as a by-product of the Jones oxidation of 15. Finally, the synthesis of optically pure (-)-1 and (+)-1, starting with the keto acids (+)-2 and (-)-2, is described.
    Notes: Ausgehend von 6-Chlor-3-oxo-2-oxabicyclo[3.2.1]octan-8-carbaldehyd (6) wird in einer 8stufigen Synthese racemische (5Z,13E)-11,15-Dihydroxy-16,16-dimethyl-9-oxo-18-oxa-5,13-prostadiensäure (1) (Dimoxaprost) dargestellt. Im ersten Reaktionsschritt wird dazu die ω-Seitenkette von 1 mit Hilfe der Horner-Emmons-Wittig-Reaktion und dem Phosphonat 7 in 6 eingeführt. Ringöffnung und Umlagerung von 8 führt zu dem Enon 9a mit freier Hydroxylgruppe. Dessen stereospezifische Reduktion ergibt das Diol 11a, welches analog der Corey-Synthese in fünf weiteren Reaktionsschritten in 1 übergeführt wird. Das 5-Ketoprostacyclin 17 wird dabei als Nebenprodukt isoliert. Die Synthese der beiden optischen Antipoden (-)-1 und (+)-1 wird in entsprechender Weise ausgehend von den Ketosäuren (+)-2 bzw. (-)-2 durchgeführt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198719870328
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  • 8
    Electronic Resource
    Electronic Resource
    Bisdiazo-alkane (1950)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 83 (1950), S. 137-141 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus α.ω-Diaminen wurden über die entsprechenden Diharnstoffe bzw. Diurethane α.ω-Bisdiazo-alkane mit 2-8 Kohlenstoffatomen dargestellt. Sie konnten mit Ausnahme des Bisdiazo-äthans als ölige, sehr zersetzliche Substanzen gewonnen werden. Wohldefinierte Umsetzungsprodukte konnten mit allen dargestellten Bisdiazo-Verbindungen erhalten werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19500830204
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  • 9
    Electronic Resource
    Electronic Resource
    Notiz über 2-Alkyl(Aryl)-1.3.4-dioxazolone-(5)Gekürzte Fassung des Manuskripts, das in der ursprünglichen, inhaltlich identischen Fassung am 7. November 1950 einging. Die Redaktion (1951)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 84 (1951), S. 688-689 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Einwirkung von Phosgen auf Hydroxamsäuren entstehen 2-Alkyl(Aryl)-1.3.4-dioxazolone(5), die mit Wasser Hydroxamsäuren zurückbilden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19510840807
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  • 10
    Electronic Resource
    Electronic Resource
    Synthese des 15α-Acetoxy-16,16-dimethyl-9-oxo-18-oxa-(2E,13E)-2,13-Prostadiensäure-methylestersHerrn Prof. Dr. Th. Wieland zum 65. Geburtstag in Verehrung gewidmet. (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 1739-1748 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of Methyl 15α-Acetoxy-16,16-dimethyl-9-oxo-18-oxa-(2E,13E)-2,13-ProstadienoateThis article describes a 13-step synthesis of methyl 15α-acetoxy-16,16-dimethyl-9-oxo-18-oxa-(2E,13E)-2,13-Prostadienoate (16c) from ethyl 2-oxocyclopentanecarboxylate (2). Alkylation of 2 with 5-iodopentyl acetate (3) and subsequent decarboxylation affords a synthon 4, which contains 5 carbon atoms of the upper side chain of the target compound 16. Chlorination of 4 and subsequent dehydrochlorination yields the unsaturated ketone 5. Michael addition of hydrogen cyanide leads to 6, which possesses the first carbon atom of the lower side chain in the nitrilo group. Aldehyde 10 can be obtained in four further reaction steps. The lower side chain is introduced by a Horner-Emmons-Wittig reaction with 10. Construction of the carbon skeleton of 16 is completed by a Wittig reaction on the upper side chain by reaction of aldehyde 14 with methoxy-carbonylmethylene(triphenyl)phosphorane.
    Notes: Ausgehend von 2-Oxocyclopentancarbonsäure-ethylester (2) wird in einer 13stufigen Synthese der 15α-Acetoxy-16,16-dimethyl-9-oxo-18-oxa-(2E,13E)-2.13-prostadiensäure-methylester (16c) dargestellt. Dabei wird durch Alkylierung von 2 mit Essigsäure-(5-iodpentylester) (3) nach Decarboxylierung ein Synton 4 aufgebaut, das 5 C-Atome der oberen Seitenkette des Endproduktes 16 enthält. Chlorierung von 4 und Dehydrochlorierung ergibt das ungesättigte Keton 5, aus dem durch Michael-Addition von Blausäure 6 dargestellt wird, das in der Nitrilgruppe das erste C-Atom der unteren Seitenkette besitzt. In vier weiteren Reaktionsschritten wird der Aldehyd 10 er-halten, an den mit Hilfe der Horner-Emmons-Wittig-Reaktion die untere Seitenkette ankondensiert wird. Der Aufbau des Grundgerüstes von 16 wird an der oberen Seitenkette durch eine Wittig-Reaktion mit dem Aldehyd 14 und Methoxycarbonylmethylen(triphenyl)phosphoran beendet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819781105
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