Results 221 to 230 of about 11,209 (271)

On the nitration of 2‐pyrone

Journal of Heterocyclic Chemistry, 1969
AbstractA 1:1 adducl of 2‐pyrone and nitronium fluoroborate has been delected by nmr and is a possible precursor of 5‐nitro‐2‐pyrone, a subsequently formed product. From comparison of the nmr spectra of the 1:1 adduct and 2‐methoxypyrylium fluoroborate, the adduct is believed to be the pyrylium fluoroborate derived from nitration of the carbonyl oxygen
W. H. Pirkle, M. Dines
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Synthesis of substituted ?-pyrones

Chemistry of Heterocyclic Compounds, 1972
Substituted γ-pyrones were synthesized by the acylation of phenylacetaldehyde and its enol acetate with acetic and propionic anhydrides in the presence of 70% HClO4. The mechanism of the reaction is examined, and the IR and PMR spectra of the synthesized γ-pyrones are presented. Some of their transformations were studied.
E. V. Kuznetsov, A. I. Pyshchev, G. N. Dorofeenko   +2 more
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ChemInform Abstract: SYNTHESIS OF 5,6‐DIHYDRO‐2‐PYRONE AND 2‐PYRONE

Chemischer Informationsdienst, 1974
AbstractVinylessigsäure (I) reagiert mit Formaldehyd (II) in siedendem Eisessig ′in Gegenwart von konz. Schwefelsäure in bescheidenen Ausbeuten zum 5;6‐Dihydro‐2‐pyron (III), das nach Bromierung mit n‐Bromsuccinimid (V) in Tetrachlorkohlenstoff zu (VI) und Dehydrobromierung mit Triäthylamin 2‐Pyron (VII) ergibt.
M. NAKAGAWA, M. TONOZUKA, M. OBI, M. KIUCHI, T. HINO   +4 more
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Preparation of the Geranyl-α-pyrone (±)-Aurantiacone via a New Pyrone Synthesis

Synlett, 2007
The structure of the leaf resin geranyl-α-pyrone auranti-acone isolated from Mimulus ( = Diplacus) aurantiacus (Curtis) Jeps. (Scrophulariaceae) was confirmed through synthesis. The key step is lactonization of the sensitive 5-hydroxy-3-oxopent-4-enoic acid under mild conditions, which can be released from the corresponding bispotassium salt.
Uwe Beifuss, Dietmar Schmidt, Jürgen Conrad, Iris Klaiber, Sabine Mika   +4 more
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Photocycloadditions to a pyrone analogue

Journal of Photochemistry and Photobiology A: Chemistry, 1991
Abstract Irradiation of the dicyanomethylenepyran 1 in methanol gave two dimers, 5 and 6. In the presence of ethyl vinyl ether and acrylonitrile, the major photoproducts were 9 and 12 respectively. All these results are explained by initial [2+2] cycloaddition to the exocyclic double bond of 1 to give cyclobutane intermediates, which undergo ring ...
Christopher J. Samuel, Haydn G. Beaton, Kenneth Davey, C.James Reader   +3 more
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Pyrone studies—I

Tetrahedron, 1967
Abstract Further studies on the use of pyrones for the biogenetic-type synthesis of phenolic compounds are reported. In particular some control over the direction of cyclization of the intermediate β-triketo ester chain is demonstrated. This control makes possible the synthesis of two basic types of phenolic compound from the same precursor and is ...
T. Money, F.W. Comer, G.R.B. Webster, I.G. Wright, A.I. Scott   +4 more
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An aspect of pyrone chemistry

2011
Since 1893, acetate has been regarded as a very important precursor of naturally occurring phenolic compounds. Although intensive work has been directed at the complete elucidation of this biogenetic pathway, a satisfactory method has yet to be devised for the synthesis of the polyketide chains proposed as intermediates in the acetate scheme. Labelling
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?-Pyrone derivatives

Chemistry of Heterocyclic Compounds, 1967
G. A. Garkusha, G. A. Khutornenko
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Exchange Reactions of γ-Pyrone and Synthesis of Deuterated Pyrones

Journal of the American Chemical Society, 1952
R. C. Lord, W. D. Phillips
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Exchange Reactions of 4-Pyrone and 4-Pyrone Derivatives

The Journal of Organic Chemistry, 1964
D. W. Mayo, P. J. Sapienza
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