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  • 1980-1984
  • 1975-1979  (7)
  • 1925-1929
  • 1830-1839
  • 1978  (7)
  • Organic Chemistry  (7)
  • 1
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Flexible model results for the —NH2 inversion in vinylamine are compared with microwave data published by Lovas et al. [3]. The information available on the spacing of inversion levels is found to be sufficient to rule out a planar equilibrium structure. Shifts of rotational constants upon excitation of the inversion are calculated for two predicted paths of motion derived from PRDDO geometry optimization results obtained by MiiIler & Brown [2]. Partial geometry optimization yields a path inconsistent with experiment but the path obtained from complete optimization produces shifts in excellent agreement with the observed shifts. A potential energy function compatible with experimental data on spacing of inversion levels is calculated from the observed inertia defects. The inversion angle at equilibrium is slightly smaller than the angle predicted from PRDDO calculations, and the barrier to inversion, ΔV = 1.08 ± 0.07 kcal/mol, is approximately half the PRDDO value.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 337-344 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of the 2-Butynoic Acid Dianion with Aldehydes; Synthesis of some Natural Products with 5,6-Dihydro-2H-pyran-2-one Structure1)The naturally occurring 5,6-dihydro-2H-pyran-2-ones 6a, 6b and 6e have been synthesised starting from the 2-butynoic acid dianion 1 and the aldehydes 2a  -  c with 5-hydroxy-2-alkynoates 4a  -  c as intermediates.
    Notes: Die natürlich vorkommenden 5,6-Dihydro-2H-pyran-2-onderivate 6a, 6b und 6e werden ausgehend von dem 2-Butinsäuredianion 1 und den Aldehyden 2a  -  c über die 5-Hydroxy-2-alkinsäureester 4a  -  c als Zwischenstufen synthetisiert.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dihydropyridines, IV.  -  Condensation of Aldehydes with Enediaminocarbonyl CompoundsReaction of aldehydes 1 with double molar quantities of amidinoacetic esters 5 leads to the 2,6-diaminodihydropyridine-3,5-dicarboxylates 8. 2-Amino-6-dialkylamino-4,5-dihydropyridines 12 are obtained by condensation of 1 with 3-amino-3-dialkylaminoacrylic esters 11. Pyridones 17 with bridgehead nitrogen are formed by condensation of 1 with bridged enediaminocarbonyl compounds 15.
    Notes: Die Kondensation von Aldehyden 1 mit Amidinoessigsäureestern 5 im Molverhältnis 1:2 führt zu 2,6-Diaminodihydropyridin-3,5-dicarbonsäureestern 8. 3-Amino-3-dialkylaminoacrylsäureester 11 liefern mit 1 unter analogen Bedingungen die 2-Amino-6-dialkylamino-4,5-dihydropyridine 12. Dihydropyridone 17 mit Brückenkopf-N-Atom werden durch Kondensation von 1 mit den N,N′-verbrückten Endiaminocarbonsäureestern 15 erhalten.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Incorporation of [4'-(E)-13C]4-(3-Methyl-2-butenyl)tryptophan into Clavine Alkaloids and Lysergic AcidThe 13C-enriched C-atom of the 4'(E)-methyl groups of 4-(3-methyl-2-butenyl)tryptophan (3) appears during the biosynthesis at the C-methyl group of chanoclavine (4) and at C-17 of agroclavine (5), elymoclavien (6) and lysergic acid (7).
    Notes: Das 13C-angereicherte C-Atom der 4'-(E)-Methylgruppe im 4-(3-Methyl-2-butenyl)tryptophan (3) erscheint bei der Biosynthese in der C-Methylgruppe des Chanoclavins (4) und im C-17 von Agroclavin (5), Elymoclavin (6) und Lysergsäure (7).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (±)-2,2-Diethyl-3-methyl- and (±)-2,2-Diethyl-3,6-dimethyl-6-(phenoxyacetamido)-penam-3-carboxylic acidThe title compounds 4I and 4k were synthesized as the potassium salts 4I', 4k' starting from benzyl 4-methyl-2-thiazolinecarboxylate (3a).  -  The preparation of several benzyl 2-thiazoline-4-carboxylates (type 3) from thioketones 2 and 2-metalated benzyl 2-isocyanoalkanecarboxylates 1b, d is described.
    Notes: Die im Titel genannten Verbindungen 4I und 4k wurden (als Kaliumsalze 4I' bzw. 4k') ausgehend von 5,5-Diethyl-4-methyl-2-thiazolin-4-carbonsäure-benzylester (3a) dargestellt.  -  An mehreren Beispielen wird die Synthese von 2-Thiazolin-4-carbonsäure-benzylestern (Typ 3) aus Thioketonen 2 und 2-metallierten 2-Isocyanalkansäureestern 1b und d beschrieben.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 1491-1504 
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Malondiamidines, I.  -  (3 + 3)-Condensations with 1,3-Dicarbonyl CompoundsMalondiamidines 4, 5, 8a-g, 11 and 14 are prepared from corresponding imidates using the Pinner method. The parent compound 5 undergoes condensation with double molar quantities of 1,3-dicarbonyl compounds yielding 3-(2-pyrimidyl)-2-pyridinamines 16 and 17a-g. Condensation of 1,3-dicarbonyl compounds with N,N′-bridged malondiamidine 11 furnishes 8-(2-imidazolinyl)imidazo[1,2-a]pyridines 19a-d. H/D-exchange phenomena of the 5,7-dimethyl derivative 19a are discussed. Use of 3-keto esters and tricarbonyl compounds in condensation with 11 results in formation of 26, 27 and 28, respectively.
    Notes: Die Malondiamidine 4, 5, 8a-g, 11 und 14 werden aus den korrespondierenden Imidsäureestern nach Pinner hergestellt. Die Stammverbindung 5 kondensiert mit der doppelt molaren Menge von 1,3-Dicarbonylverbindungen zu 3-(2-Pyrimidyl)-2-pyridinaminen 16 und 17a-g. Bei der Kondensation von dem N,N′-verbrückten Malondiamidin 11 mit 1,3-Dicarbonylverbindungen resultieren die 8-(2-Imidazolinyl)imidazo[1,2-a]pyridine 19a-d. Die H/D-Austauschphänomene des 5,7-Dimethylderivates 19a in der 1H-NMR-Spektroskopie werden diskutiert. Der Einsatz von 3-Ketocarbonsäureestern und 1,3,5-Tricarbonylverbindungen in der Kondensation mit 11 führt zu den Tri- bzw. Tetracyclen 26, 27 und 28.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dihydropyridines V.  -  Synthesis of AminodihydropyridonesMichael addition of amidinoacetic esters 1 to aralkylidene malonates 5 is followed by ring closure to 2-amino-4-aryl-6-oxo-1,4,5,6-tetrahydropyridine-3,5-dicarboxylates 11a-m. Analogous addition of 1 to ethyl cinnamate furnishes the monoester 13. 4-Aralkylidene-2-methyloxazole-5(4H)-ones 14 are attacked by 1 with subsequent opening of the oxazole ring leading to 5-acetylamino-2-amino-4-aryl-6-oxo-1,4,5,6-tetrahydropyridine-3-carboxylates 15a-c.
    Notes: Die cyclisierende Michael-Addition von Amidinoessigsäureestern 1 an die Aralkylidenmalonsäurediester 5 fährt zu den 2-Amino-4-aryl-6-oxo-1,4,5,6-tetrahydropyridin-3,5-dicarbonsäureestern 11a-m. Die analoge Addition an Zimtsäure-ethylester liefert den Monoester 13. An 4-Aralkyliden-2-methyloxazol-5(4H)-one 14 wird 1 unter nachfolgender Öffnung des Oxazolrings zu den 5-Acetylamino-2-amino-4-aryl-6-oxo-1,4,5,6-tetrahydropyridin-3-carbonsäureestern 15a-c addiert.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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