Results 171 to 180 of about 20,891 (238)
Zr-MOF-glutaraldehyde-Adn@Fe<sub>3</sub>O<sub>4</sub> nanocomposite: as a new adsorbent for removal of methylene blue and heterogeneous nanocatalyst for the synthesis of tetrahydrobenzo[b]pyran derivatives. [PDF]
Sci RepYazdiamiri F +3 more
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l-Arg@ZY-Fe<sub>3</sub>O<sub>4</sub> mesoporous nanomaterial: a novel magnetically recoverable bio-organocatalyst for three-component synthesis of 4<i>H</i>-pyran and -chromene derivatives. [PDF]
Nanoscale AdvKalhor M, Zebardast S.
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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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Chemische Berichte, 1970
AbstractWie am Beispiel von 4‐Hydroxy‐cumarin und Barbitursäure gezeigt werden konnte, gehen diese β‐Dicarbonylverbindungen mit Aldehyden und Phenylacetylen keine Dreikohlenstoff‐kondensation ein. Es entstehen kondensierte Pyrane durch 1.4‐Addition des Phenylacetylens an das ungesättigte Zwischenprodukt aus Aldehyd und Dicarbonylverbindung.
Karl Ernst Schulte +2 more
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AbstractWie am Beispiel von 4‐Hydroxy‐cumarin und Barbitursäure gezeigt werden konnte, gehen diese β‐Dicarbonylverbindungen mit Aldehyden und Phenylacetylen keine Dreikohlenstoff‐kondensation ein. Es entstehen kondensierte Pyrane durch 1.4‐Addition des Phenylacetylens an das ungesättigte Zwischenprodukt aus Aldehyd und Dicarbonylverbindung.
Karl Ernst Schulte +2 more
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A novel synthetic approach to pyran-2,4-dione scaffold production: Microwave-assisted dimerization, cyclization, and expeditious regioselective conversion into β-enamino-pyran-2,4-diones [PDF]
Tetrahedron Letters, 2020 Here, we report a novel, green, simple, low-cost, and rapid methodology for the high-yield production of pyran-2,4-dione scaffolds under microwave irradiation.
Ahmed Sarhan +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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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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ChemInform Abstract: PHOTOCHEMICAL REARRANGEMENT OF 4H‐PYRANS AND OF DIENONES TO 2H‐PYRANS
Chemischer Informationsdienst, 1980AbstractDie Photoreaktivität der 4H‐Pyrane (I) wurde mit Hilfe von Fluoreszenz‐ und Phosphoreszenz‐Messungen, Desaktivierungsmessungen für den Singulettzustand und durch Bestimmung von Quantenausb.
F. FOURNIER +3 more
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