Library

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
  • 1980-1984  (16)
  • 1925-1929
  • 1830-1839
  • 1981  (16)
  • Organic Chemistry  (10)
  • General Chemistry  (6)
  • 1
    Electronic Resource
    Electronic Resource
    Rates of Proton Abstraction from Conjugated Dienes in the Gas Phase (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1058-1062 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rates of proton transfer from 2, 4-hexadiene, 1, 3-cycloheptadiene, cyclopentadiene and acetone to t-butoxide have been measured in the gas phase using pulsed-ion-cyclotron-resonance spectroscopy. The rate constants are (units of 10-10 cm3 molecule-1 s-1): 2.7 ± 0.4, 3.8 ± 0.4, 6.1 ± 0.7 and 10.8 ± 1.5, respectively. These results are analyzed in terms of the properties of the encounter complex and reaction transition states. The reaction profile for t-butoxide + cyclopentadiene is modeled using RRKM theory and an estimate for the central barrier height is obtained.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19810640411
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Mikrobielle Reduktion 2,2-disubstituierter Cyclopentan-1,3-dione. Darstellung chiraler Cyclopentanderivate für die Synthese von 8-Methyl-prostaglandinen (1981)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 323 (1981), S. 729-736 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Microbial Reduction of 2,2-Disubstituted Cyclopentan-1,3-diones. Synthesis of Chiral Cyclopentane Derivatives Useful as Intermediates for 8-Methyl ProstaglandinsThe microbial reduction of the 2,2-disubstituted cyclopentan-1,3-diones 3a—c giving rise to the chiral compounds 2, 4b and 4c is described.The incubation products can be used as intermediates for 8-methyl prostaglandins.The structures of the fermentatively formed compounds, including their chirality and optical purity have been established by comparison with authentic specimen (cp. 2) or by chemical and spectroscopic methods (cp. 4b, 4c) respectively.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19813230505
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Malondiamidine, III. Synthese und Kondensationsreaktionen des 1,2,3,4,6,7-Hexa-hydro-7-imino-1,4-dimethyl-5H-1,4-diazepin-5-ons (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1545-1549 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Malonodiamidines, III.  -  Synthesis and Condensation Reactions of 1,2,3,4,6,7-Hexahydro-7 imino-1,4-dimethyl-5H -1,4-diazepin-5-oneDiethyl malonodiimidate dihydrochloride (I) and N-methylethylenediamine yield in ethanol the N,N'-bridged malonodiamidine salt 2b, whereas 1 and N,N'-dimethylethylenediamine fail to give the 2b analogous salt 4. Instead the 1 H-1,4-diazepine-5,7-diimine hydrochloride 5 is obtained in low yield. Under hydrolytic reaction conditions the hydrochloride of the title compound is obtained in 56% yield. [3 + 3]-Condensations of the corresponding base 7 with 2,4-pentanedione and α,β-unsaturated carbonyl compounds lead to the diazepines 8, 9, and 10. 1 H-[1,4]diazepino-[5,6-b]quinolines 12a- f are obtained by condensation of 6 with the isatines 11.
    Notes: Malondiimidsäure-diethylester-dihydrochlorid (1) liefert mit N-Methylethylendiamin in Ethanol das N,N'-verbrückte Malondiamidiniumsalz 2b. Umsetzung von 1 mit N,N'-Dimethylethylendiamin führt wider Erwarten nicht zum 2b analogen Salz 4, sondern in geringer Ausbeute zum 1 H-1,4-Diazepin-5,7-diiminsalz 5. Unter hydrolytischen Reaktionsbedingungen wird das Hydrochlorid der Titelverbindung mit 56% Ausbeute erhalten. Die zugrundeliegende Base 7 geht mit 2,4-Pentandion und α,β-ungesättigten Carbonylverbindungen [3 + 3]-Kondensationen zu den Diazepinen 8, 9 und 10 ein. Die Isatine 11 kondensieren mit 7 zu den 1 H-[1,4]Diazepino[5,6-b]-chinolinen 12a- f.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810904
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Di- und Polyaminozucker, XXVI. Synthesen von Derivaten der 3,6-Diamino-3,6-didesoxy-D-galactose, 3,4,6-Triamino-3,4,6-tridesoxy-D-galactose und 3,4,6-Triamino-3,4,6-tridesoxy-D-glucose (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1982-1993 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Di- and Polyamino Sugars, XXVI.  -  Syntheses of Derivatives of 3,6-Diamino-3,6-dideoxy-D-galactose, 3,4,6-Triamino-3,4,6-trideoxy-D-galactose and 3,4,6-Triamino-3,4,6-trideoxy-D-glucoseThe syntheses of the title compounds were accomplished by single or twofold inversion of the configuration at C-4 of 3,6-diazido-3,6-dideoxy-1,2-O-isopropylidene-α-D-glucopyranose (6).  -  The oxidation of 6 to the ketone 18 and subsequent reduction with sodium tetrahydroborate were examined. 18 was easily transformed into the C-3 epimeric ribo-ulose 19. 18 and 19 yielded the enol acetate 20. The reduction of 18 afforded an epimeric mixture of 6 (gluco) and 11 (galacto) while 19 and 20 were stereoselectively reduced to form the allo isomer 22.
    Notes: Die Synthese der Titelverbindungen erfolgte über die 3,6-Diazido-3,6-didesoxy-1,2-O-isopropyliden-α-D-glucopyranose (6) durch einfache oder doppelte Inversion der Konfiguration an C-4.  -  Die Oxidation von 6 zum Keton 18 und die anschließende Reduktion mit Natrium-tetrahydroborat wurden untersucht. 18 epimerisierte an C-3 zur ribo-Ulose 19. Beide Ulosen 18 und 19 wurden in das Enolacetat 20 übergeführt. Die Reduktion von 18 ergab ein Epimerengemisch bestehend aus 6 (gluco) und 11 (galacto), während 19 und 20 stereoselektiv unter Bildung von 22 (allo) reduziert wurden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119811107
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Notiz zur Darstellung partiell hydrierter 5-Hydroxy-1,7-naphthyridin-Derivate (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 2087-2089 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Note on the Synthesis of Partially Hydrogenated 5-Hydroxy-1,7-naphthyridine DerivativesThe preparation of 5,6,7,8-tetrahydro-1,7-naphthyridine-5-ol (5) and of 1,2,3,4-tetrahydro-1,7-naphthyridine-5-ol (6) from ethyl 7-benzyl-5-oxo-5,6,7,8-tetrahydro-1,7-naphthyridine-6-carboxylate (1) is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119811118
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Di- und Polyaminozucker, XXV. Synthesen N-verknüpfter Saccharide  -  Reaktionen von Amino- mit Epoxyzuckern (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 2139-2163 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Di- and Polyamino Sugars, XXV.  -  Syntheses of N-Connected Saccharides  -  Reactions of Amino with Epoxy SugarsSeveral diglycos-6-(3)-ylamines (secondary amines) and triglycos-6-(3)-ylamines (tertiary amines) were synthesized via ring opening of the 5,6-anhydro sugars 1 and 18 by 6-amino-6-deoxy-D-glucose, 3-amino-3-deoxy-D-glucose, and 3-amino-3-deoxy-D-altrose derivatives and could be obtained as the unblocked hydrochlorides. Furthermore, the reaction of these di- and triglycos-6-(3)-ylamines which have potential amino groups in form of the azido functions with another anhydro sugar led after hydrogenation to a number of pseudo tri-, tetra-, and pentasaccharides.
    Notes: Die 5,6-Anhydrozucker 1 und 18 wurden mit 6-Amino-6-desoxy-D-glucose-, 3-Amino-3-desoxy-D-glucose- und 3-Amino-3-desoxy-D-altrose-Derivaten unter Öffnung des Oxiranringes durch die Aminogruppen umgesetzt. Sowohl Diglycos-6-(3)-ylamine (sekundäre Amine) als auch Triglycos-6-(3)-ylamine (tertiäre Amine) wurden isoliert, derivatisiert und zu den freien Zuckern deblockiert. Darüber hinaus konnten diese Saccharide, die potentielle Aminogruppen in Form der Azidofunktion enthalten, nach Hydrierung erneut mit einem Anhydrozucker zur Reaktion gebracht werden. Auf diese Weise wurden aus drei, vier und fünf Zuckermolekülen aufgebaute Verbindungen synthetisiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119811206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    N-Acyldehydro-α-aminosäuren aus N-Formyldehydro-α-amino-säure-methylestern (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1469-1475 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Acyl Dehydro-α-amino Acids from N-Formyl Dehydro-α-amino Acid EstersOn treatment with methyl potassioisocyanoacetate (2), aldehydes and ketones 1 give N-anionized N-formyl dehydro-α-amino acid methyl esters 3. Compound 3 with R1 = CH3, R2 = H is obtained by base induced ring opening of methyl 2-oxazoline-4-carboxylate 5.  -  Acylation of 3, followed by deformylation of the intermediates 6, yields N-acyl dehydro-α-amino acid methyl esters 7 which can be hydrolyzed to the N-acyl dehydro-α-amino acids 8.
    Notes: Aus Aldehyden und Ketonen 1 erhält man mit Kalioisocyanessigsäure-methylester (2) durch Formylaminomethylenierung die am Stickstoff anionisierten N-Formyldehydro-α-aminosäure-methylester 3. Für 3 mit R1 = CH3 und R2 = H ist die baseninduzierte Ringöffnung des 2-Oxazolin-4-carbonsäure-methylesters 5 günstiger.  -  Durch N-Acylierung von 3, gefolgt von Entformylierung der Zwischenstufen 6, erhält man die N-Acyldehydro-α-aminosäureester 7, die zu den N-Acyldehydro-α-aminosäuren 8 hydrolysierbar sind.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810818
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Dihydropyridine, VI. Diimidomalonsäurederivate in der Hantzsch-Pyridin-SyntheseHerrn Prof. Dr. Herbert Grünewald zum 60. Geburtstag gewidmet. (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1523-1533 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dihydropyridines, VI1).  -  Derivatives of Diimido Malonic Acid in the Hantzsch Pyridine SynthesisOne-pot-condensation of aldehydes 6, 2,2′-methylenediimidazoline hydrochloride (7) and β-dicarbonyl compounds 10 leads to 1,2,3,7-tetrahydro-8-(2-imidazoline-2-yl)imidazo[1,2-a]pyridine hydrochloride 11. Michael addition of 7 to α,β-unsaturated ketones is followed by ring closure to give 16, 17, and 18. Condensation of the free base 8a with aldehydes 6 and 1,3-cyclohexanedione yields the fused imidazopyridines 19a-d. Compounds 20 and 21 are prepared by use of a second enamine in the one-pot-synthesis, thus furnishing another basic centre. 2,2′-Methylenedi(2-thiazoline) hydrochloride (22) is prepared by condensation of diethyl malonodiimidate and 2-amino
    Notes: Die Dreikomponenten-Kondensation von Aldehyden 6, 2,2′-Methylendiimidazolin-hydrochlorid (7) und β-Dicarbonylverbindungen 10 führt zu 1,2,3,7-Tetrahydro-8-(2-imidazolin-2-yl)imidazo-[1,2-a]pyridin-hydrochloriden 11. Die Verbindungen 16, 17 und 18 werden durch cyclisierende Michael-Addition von 7 an α,β-ungesättigte Ketone erhalten. Die freie Base 8a kondensiert mit 1,3-Cyclohexandion und den Aldehyden 6 zu den anellierten Imidazopyridinen 19a-d. Einsatz eines zweiten Enamins in der Dreikomponenten-Reaktion liefert die Verbindungen 20 und 21 mit einem weiteren basischen Zentrum. 2,2′-Methylendi(2-thiazolin)-hydrochlorid (22) wird durch Kondensation von Malondiimidsäure-diethylester und 2-Aminoethanthiol-hydrochlorid erhalten. Natronlauge liefert die freie Base 8b. Die 2,3-Dihydro-8-(2-thiazolin-2-yl) 7H-thiazolo[3,2-a]-pyridine 23, 25, 26, 28 und 29 sind durch cyclisierende Michael-Addition von 8b an verschiedene α,β-ungesättigte Carbonylverbindungen in Ethanol oder Eisessig zugänglich.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810902
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Heterocyclen aus Nitroalkenen, I. Pyrrole durch cyclisierende Michael-Addition von EnaminenHerrn Prof. Dr. Herbert Grünewald zum 60. Geburtstag gewidmet. (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1534-1544 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Heterocycles from Nitroalkenes, I.  -  Pyrroles via Michael Addition of EnaminesThe principle of a general pyrrole synthesis via cyclising Michael addition of enamines to nitroalkenes is outlined. Condensation of the nitroalkene 7 with various enamines yields the pyrroles 9, 11, 12, 14, 15, 17, 18, 20, 22, 26, 27, 29, and 31. Reaction of 1-nitro-1,2-diphenylethene and the enamine 8 furnishes the pyrrolo[2,1-a]isoquinoline 32 while addition of 8 to 1-nitrocyclohexene is followed by ring closure to the indolo[2,1-a]isoquinoline 33. The pyrrole 14 can also be prepared by multiple-component syntheses, further examples of which are the syntheses of the pyrroles 35, 36, 37, and 38. Scope and advantages of the presented pyrrole synthesis are discussed.
    Notes: Das Prinzip einer breit anwendbaren Pyrrolsynthese durch cyclisierende Michael-Addition von Enaminen an Nitroalkene wird formuliert. Kondensation des Nitroalkens 7 mit verschiedenen Enaminen liefert die Pyrrolderivate 9, 11, 12, 14, 15, 17, 18, 20, 22, 26, 27, 29 und 31. Die Reaktion von 1-Nitro-1,2-diphenylethen mit dem Enamin 8 führt zum Pyrrolo[2,1-a]isochinolin 32, während Addition von 8 an 1-Nitrocyclohexen das Indolo[2,1-a]isochinolin 33 ergibt. Die Synthese des Pyrrols 14 läßt sich auch in Mehrkomponenten-Varianten durchführen. Weitere Beispiele sind die Synthesen der Pyrrole 35, 36, 37 und 38. Anwendungsbreite und Vorteile der vorgestellten Pyrrolsynthese werden diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810903
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Zuckertosylate via p-Toluolsulfinsäureester. p-Toluolsulfinimidazolid als Reagenz zur halogenidfreien Sulfinesterbildung (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1354-1360 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sugar Tosylates via p-Toluenesulfinic Acid Esters.  -  p-Toluenesulfinimidazolide  -  A Reagent for Formation of Sulfinic Acid Esters without Using HalidesThe reaction of the protected sugar derivatives 1, 4, 7, 10, 13, 16, 19 and 20 with p-toluenesulfin-imidazolide prepared from p-toluenesulfinic acid and N,N'-carbonyldiimidazole yields the corresponding p-toluenesulfinic esters 2, 5, 8, 11, 14, 17, 20 and 22. With the exception of 20 and 22, these products can be oxidized with m-chloroperbenzoic acid in high yields and short overall reaction times to the tosylates 3, 6, 9, 12, 15 and 18.
    Notes: Durch Umsetzung der blockierten Zuckerderivate 1, 4, 7, 10, 13, 16, 19 und 21 mit dem aus p-Toluolsulfinsäure und N,N'-Carbonyldiimidazol intermediär gebildeten p-Toluolsulfinimidazolid werden die p-Toluolsulfinsäureester 2, 5, 8, 11, 14, 17, 20 und 22 erhalten. Daraus lassen sich mit Ausnahme von 20 und 22 in hohen Ausbeuten und insgesamt kurzer Reaktionszeit die entsprechenden Tosylate 3, 6, 9, 12, 15 und 18 durch Oxidation mit m-Chlorperbenzoesäure darstellen.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810803
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...