Results 231 to 240 of about 44,043 (291)

Disproportionation of pyrans

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, A. F. Blinokhvatov, K. V. Mityurina, Z. N. Parnes, D. N. Kursanov   +4 more
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New polycyclic pyran ring systems

Journal of Heterocyclic Chemistry, 1978
AbstractReaction 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, 1990
N-(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, V. S. Rakhmatullina, M. G. Safarov   +2 more
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ChemInform Abstract: PYRANS, 100. 5,6‐DIHYDRO‐2H‐PYRAN‐3(4H)‐ONE AS A SYNTHON FOR PYRAN‐ANNULATED HETEROCYCLIC COMPOUNDS

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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ChemInform Abstract: KONDENSIERTE PYRANE

Chemischer Informationsdienst. Organische Chemie, 1970
AbstractVersuche, 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, VOLKER VON WEISSENBORN, GEORG L. TITTEL   +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, 1971
Irradiation 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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Synthesis of Novel Hybrid 4H-Pyran-lipoic and 4H-Pyran-azetidine Derivatives

Synthesis, 2017
In this study, a molecular hybridization strategy was used to design and synthesize two novel series of hybrid compounds: 4H-pyran-lipoic and 4H-pyran-azetidine, employing ammonium hydroxide and involving the participation of aldehydes, malononitrile, and compounds derived from β-ketoesters to obtain the products with good yields.
Miguel Vázquez, Fernando Hernández-Borja, Leticia Contreras, Julio López, Yolanda Alcaraz, David Cruz, Samuel Estrada-Soto, Francisco Delgado   +7 more
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Stereocontrolled Synthesis of Highly Functionalized Spirocyclic Pyrans.

ChemInform, 2006
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Stephen J, Hobson, Rodolfo, Marquez
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5-(Trimethylstannyl)-2H-pyran-2-one and 3-(Trimethylstannyl)-2H-pyran-2-one:  New 2H-Pyran-2-one Synthons

The Journal of Organic Chemistry, 1996
5-(Trimethylstannyl)-2H-pyran-2-one (11) and 3-(trimethylstannyl)-2H-pyran-2-one (30), readily prepared from the corresponding bromo-2H-pyran-2-ones, undergo Pd(0)-catalyzed coupling reactions with a variety of enol triflates to give 5- and 3- substituted 2H-pyran-2-ones, respectively. This reaction is applicable to the enol triflates of 14beta-hydroxy-
Zhi, Liu, Jerrold, Meinwald
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Kondensierte Pyrane, 3. Mitt.

Archiv der Pharmazie, 1978
AbstractPyranopyrimidincarbonsäureester lassen sich aus Barbitursäuren, Paraformaldehyd und ungesättigten Carbonsäureestern darstellen. Drei daraus durch Verseifung erhaltene Pyranopyrimidincarbonsäuren wurden auf antiphlogistische Wirksamkeit geprüft.
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