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  • 1
    Electronic Resource
    Electronic Resource
    Cycloadditions, 27Part 26: G. Himbert, D. Fink, J. Prakt. Chem., in press.. The Thermal Rearrangement of the Bicyclo[2.2.2]- to Bicyclo[3.2.1]octadiene Moiety in Tricyclic Lactams (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1255-1260 
    Details
    ISSN: 0947-3440
    Keywords: Allenes ; Hydrogen bonds ; Cycloadditions, Diels-Alder, intramolecular ; Rearrangements ; Polycycles ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tricyclic lactams 4a-h, possessing a bicyclo[2.2.2]octadiene moiety, obtained by intramolecular Diels-Alder reaction of the vinylidene malondiamides 1a-h, generally isomerize in boiling xylene to give the new lactams 7a-h, now bearing a bicyclo[3.2.1]octadiene part. The difference in the rates of the isomerizations 4 → 7 and the results with the nitro - and methoxy-substituted derivatives 4i-l are in accordance with the proposed intermediate zwitterion 6, which is formed by the migration of one vinyl group from position 1 to position 5 of the lactam moiety.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970631
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  • 2
    Electronic Resource
    Electronic Resource
    Cycloadditions, 25. - Synthesis and Reactions of sec-N-Aryl-2-methyl-2,3-butadienamides (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 435-439 
    Details
    ISSN: 0947-3440
    Keywords: 2,3-Butadienamides ; Intramolecular Diels-Alder reaction ; Cycloadditions ; Allenes ; Amides ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 2-methyl-2,3-butadienoyl chloride 1 with the N-aryl- or the N-hetarylamines, 2a-f and 2g, h, respectively, in the ratio 1 : 2 (or 1 : 1 in the presence of triethylamine) furnishes the corresponding allenamides 3a-h, accompanied by the HCl adducts, the 3-chloro-2-methyl-3-butenamides 4a-g, or the 3-butynamide 5h. Heating of the allenamides bearing a benzenoid (3a-e) or thiophene (3h) nucleus does not generate any defined products; only the amides bearing the 1-naphthyl (3f) and the furfuryl (3g) moiety undergo an intramolecular Diels-Alder reaction to give the oligocyclic compounds 6 and 7. However, heating of the benzenoid allenamides 3a-c in the presence of tolyl isocyanate furnishes, via the N-carbamoyl-amides 10a-c, the intramolecular Diels-Alder products 11a-c, whereby the monocyclic arene has functioned as diene. Reaction of 1 with the 2-aminofuran derivative 2i leads directly to the Diels-Alder product 9, a 2 : 1 adduct, whereby the initially formed amide 3i and the intramolecular Diels-Alder product 8 are not isolated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970223
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  • 3
    Electronic Resource
    Electronic Resource
    Cycloadditionen, 15. Einfluß von Substituenten in p-, m- und o-Position am Aromaten auf die intramolekulare Diels-Alder-Reaktion von Allencarbonsäure-aniliden und -phenylestern (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 1161-1173 
    Details
    ISSN: 0009-2940
    Keywords: Diels-Alder reactions ; Allenecarboxanilides ; Aryl allenecarboxylates ; Cyclizations ; MNDO calculations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cycloadditions, 15. - Influence of Substituents in P-, m-, and o Position of the Arene onto the Intramolecular Diels-Alder Reaction of Allenecarboxylic Acid Anilides and Phenyl EstersThe ylides 3 and 8 (synthesized via the bromoacetic acid amides 1 and -esters 6 and via the phosphonium bromides 2 and 7) react with ketene to give the allenecarboxanilides 4 and the phenyl allenecarboxylates 9. Thermolysis in boiling xylene of all derivatives yields the Diels-Alder products 5 and 10. Only the m-methoxyaniline derivative 4b furnishes besides 5b (40%) four different quinolinone derivatives 13-16 (total 60%). The 4-methylene derivatives 13 and 14 are transformed by base to give the aromatic 4-methyl-2(1H)-quinolinones 15 and 16. The enol ether group of the tricyclus 5b (isolated in mixture with 16) is hydrolysed by acid catalysis (formation of 17). It is tried to rationalize the different velocities of the Diels-Alder reactions 4 → 5 and 9 → 10 by MNDO calculations.
    Notes: Die aus den Bromessigsäureamiden 1 und -estern 6 über die Phosphoniumbromide 2 und 7 erhältlichen Ylide 3 und 8 reagieren mit Keten zu den Allencarboxaniliden 4 bzw. den Allencarbonsäurephenylestern 9. Bei der Thermolyse in siedendem Xylol geben alle Derivate die Diels-Alder-Produkte 5 bzw. 10. Nur das m-Methoxyanilin-Derivat 4b liefert neben 5b (40%) vier verschiedene Chinolinon-Derivate 4b liefert neben 5b (40%) vier verschiedene Chinolinon-Derivate 13-16 (zusammen 60%). Die 4-Methylen-Derivate 13 und 14 lassen sich basenkatalysiert in die aromatischen 4-Methyl-2(1H)-chinolinone 15 und 16 umwandeln. Die Enolether-Gruppierung des im Gemisch mit 16 isolierten Tricyclus 5b wird säurekatalysiert hydrolysiert (Bildung von 17). Es wird versucht, die unterschiedlichen Geschwindigkeiten der Diels-Alder-Reaktionen 4 → 5 bzw. 9 → 10 durch MNDO-Berechnungen zu deuten.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220623
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