Results 131 to 140 of about 5,053 (175)
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Chemische Berichte, 1961
AbstractMonocyclische α‐ und γ‐Pyronen durch Umsetzung mit aliphatischen und aromatischen Grignard‐Verbindungen einfach und in guten Ausbeuten herstellbar. Die Reaktionen sowie die UV‐ und IR‐Spektren der α‐Pyrane stehen in Einklang mit der cyclischen Struktur.
Rudolf Gompper, Otto Christmann
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AbstractMonocyclische α‐ und γ‐Pyronen durch Umsetzung mit aliphatischen und aromatischen Grignard‐Verbindungen einfach und in guten Ausbeuten herstellbar. Die Reaktionen sowie die UV‐ und IR‐Spektren der α‐Pyrane stehen in Einklang mit der cyclischen Struktur.
Rudolf Gompper, Otto Christmann
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Chemistry of Heterocyclic Compounds, 1983
Data on the chemistry of monocyclic, unsaturated, six-membered, oxygen-containing heterocycles, viz., 4H-pyrans, are correlated and systematized for the first time. The methods for their synthesis, their transformations, and spectroscopic data for them are discussed. The interest in these compounds, which has increased recently, is due to the fact that
O. V. Drygina, A. D. Garnovskii
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Data on the chemistry of monocyclic, unsaturated, six-membered, oxygen-containing heterocycles, viz., 4H-pyrans, are correlated and systematized for the first time. The methods for their synthesis, their transformations, and spectroscopic data for them are discussed. The interest in these compounds, which has increased recently, is due to the fact that
O. V. Drygina, A. D. Garnovskii
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Pyrane, 84. Hexahydrobenzotripyrane
Liebigs Annalen der Chemie, 1980AbstractDie Hexahydrobenzotripyrane 5 und 6 lassen sich durch katalytisches Hydrieren des Benzotripyranons 3 gewinnen, die weniger symmetrischen Isomere 21 und 12 aus der 1,2,4‐Benzoltriyltris(3‐oxypropionsäure) 16c durch Ringschlußreaktionen sowie katalytisches Hydrieren.
Claus Schmiz, Fritz Eiden
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Chemistry of Heterocyclic Compounds, 1985
Data on methods of synthesis, transformations, and spectroscopy of monocyclic six-membered, oxygen-containing heterocycles, viz., 2H-pyrans, are correlated and systematized for the first time in this review.
O. V. Drygina +2 more
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Data on methods of synthesis, transformations, and spectroscopy of monocyclic six-membered, oxygen-containing heterocycles, viz., 2H-pyrans, are correlated and systematized for the first time in this review.
O. V. Drygina +2 more
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Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 1976
1. It was established that the hydrogen atom in sym-octahydroxanthene was a high hydride mobility. 2. The disproportionation of sym-octahydroxanthene was effected using acids and a mechanism was proposed for this reaction. 3. A mechanism was proposed for the formation of pyrylium salts from 1,5-diketones.
V. G. Kharchenko +4 more
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1. It was established that the hydrogen atom in sym-octahydroxanthene was a high hydride mobility. 2. The disproportionation of sym-octahydroxanthene was effected using acids and a mechanism was proposed for this reaction. 3. A mechanism was proposed for the formation of pyrylium salts from 1,5-diketones.
V. G. Kharchenko +4 more
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New polycyclic pyran ring systems
Journal of Heterocyclic Chemistry, 1978AbstractReaction of 1‐oxo‐3‐dialkylamino‐1H‐naphtho[2,1‐b]pyrans, 4‐hydroxycoumarin and formaldehyde gave rise to the formation of 1‐oxo‐2‐((2‐oxo‐4′‐hydroxy‐2′H‐1′‐benzopyran‐3′‐yl)‐melhyl J‐3‐dialkylamino‐1H‐naphtho[2,1‐b]pyrans. When these compounds were refluxed in glacial acetic acid, cyclization occurred and 6,8‐dioxo‐6H,7H,07‐,5,15,16 ...
MAZZEI, MAURO, G. Roma, A. Ermili
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Liquid-crystal pyran derivatives
Chemistry of Heterocyclic Compounds, 1990N-(4-Substituted benzylidene)-4′-[(3,6-dihydro-4-methyl-2H-pyran-3-yl)amino]anilines, which have the properties of smectic liquid crystals over the temperature range 76–115‡C, were synthesized.
M. M. Murza +2 more
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Chemischer Informationsdienst, 1985
AbstractDihydropyranon (I) läßt sich nur in Einzelfällen,′ z.B. mit den Aminoketonen (XX), zu anellierten Heterocyclen wie (XXI) umsetzen.
F. EIDEN, K. T. WANNER
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AbstractDihydropyranon (I) läßt sich nur in Einzelfällen,′ z.B. mit den Aminoketonen (XX), zu anellierten Heterocyclen wie (XXI) umsetzen.
F. EIDEN, K. T. WANNER
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ChemInform Abstract: KONDENSIERTE PYRANE
Chemischer Informationsdienst. Organische Chemie, 1970AbstractVersuche, aus dem Cumarin (I) mit Formaldehyd (II) und Phenylacetylen (III) durch eine Dreikohlenstoffkondensation das Propinylcumarin (IV) darzustellen, lieferten neben 82% Dicumarol (VI) das Pyranobenzopyran (V) in 14%iger Ausbeute.
KARL ERNST SCHULTE +2 more
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Photochemical rearrangement of 4H-pyran-4-ones to 2H-pyran-2-ones
Journal of the Chemical Society D: Chemical Communications, 1971Irradiation of 2,6-disubstituted-3,5-diphenyl-4H-pyran-4-ones (Ia,b) with a medium-pressure mercury lamp yielded 3,6-diphenyl-4,5-disubstituted-2H-pyran-2-ones (IVa,b).
N. Ishibe, M. Odani, M. Sunami
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