Results 131 to 140 of about 90,377 (200)

4H-Pyran-4-one derivatives:

2009
A series of 3-hydroxy-6-methyl-2-((4-substitutedpiperazin-1-yl)methyl)-4H-pyran-4-on e structured compounds were synthesized by reacting 5-hydroxy-2-methyl-4H-pyran-4-one with suitable piperazine derivatives using Mannich reaction conditions. Antibacterial activities of the compounds for E. coli, S. paratyphi, S. flexneri, E.
Us, Demet, Gurdal, Ece, Berk, Barkin, Oktem, Sinem, Kocagoz, Tanil, Caglayan, Berrak, Kurnaz, Isil Aksan, Erol, Dilek Demir   +7 more
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ChemInform Abstract: SYNTHETIC APPROACHES TO THE 4H‐PYRAN RING

Chemischer Informationsdienst, 1980
AbstractReview: Verschiedene Synthesen für Verbindungen mit 4H‐Pyran‐Ringen (I) werden diskutiert.
C. SEOANE, J. L. SOTO, M. QUINTEIRO
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A convenient preparation of tetrahydro-4H-pyran-4-one

Journal of the Chemical Society C: Organic, 1970
Tetrahydro-4H-pyran-4-one has been prepared in a two-stage process from 3-chloropropionyl chloride, in 45% overall yield.
G. R. Owen, C. B. Reese
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Photolysis of 2,6-diphenyl-4H-pyran-4-thione

Journal of the Chemical Society D: Chemical Communications, 1970
Photolysis of 2,6-diphenyl-4H-pyran-4-thione in dioxan results in desulphurization to give 2,2′,6,6′-tetraphenyl-4,4′-bi(pyranylidene).
N. Ishibe, M. Odani, K. Teramura
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Synthesis of 4H-pyrans by O-cyclization of 1,5-diketones

Chemistry of Heterocyclic Compounds, 1992
Substituted 4H-pyrans were obtained in high preparative yields by the reaction of 1,5-diketones with acetic anhydride and boron trifluoride etherate in diethyl ether. It is assumed that the heterocyclization of 1,5-diketones includes a step involving the formation and transformations of an acyloxy carbonium ion.
A. F. Blinokhvatov, O. V. Markovtseva, M. N. Nikolaeva   +2 more
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[Natural derivatives of 4H-pyran-4-one].

Ceska a Slovenska farmacie : casopis Ceske farmaceuticke spolecnosti a Slovenske farmaceuticke spolecnosti, 2006
The present review paper describes the natural derivatives of 4H-pyran-4-one (simple, benzo- and dibenzo-derivatives). It includes their origin, use, and particularly in the case of flavonoids their biological actions and therapeutic use.
M, Uher, J, Cizmárik
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Friedländer reaction on 2-amino-3-cyano-4H-pyrans: Synthesis of derivatives of 4H-pyran [2,3-b] quinoline, new tacrine analogues

Bioorganic & Medicinal Chemistry Letters, 1997
The unprecedented Friedlander reaction of densely functionalized 2-amino-3-cyano-4H-pyrans (1) with cyclohexanone has afforded in one step and good yield 5-amino-4-aryl-3-ethoxycarbonyl-2-methyl-6,7,8,9-tetrahydro-4H-pyran[2,3-b]quinolines (2), novel amino-substituted fused pyran derivatives. These compounds are new tacrine analogues.
Angeles Martínez-Grau, JoséL Marco
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Theoretic and Experimental Study of Photoprocesses in Substituted 4-Dicyanomethylene-4H-pyrans

High Energy Chemistry, 2005
The photoprocesses in substituted 4-dicyanomethylene-4H-pyran (DCM) derivatives were studied theoretically and experimentally. The experimental spectral and luminescent parameters of the molecules under study are in good agreement with the results of quantum-chemical calculations.
Pomogaev, Vladimir A., Svetlichnyi, Valerii A., Pomogaeva, A. V., Svetlichnaya, N. N., Kopylova, Tatyana N.   +4 more
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Synthesis, molecular docking and biological evaluation of new steroidal 4H-pyrans

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2014
A series of new steroidal 4H-pyrans (4-6) have been synthesized from steroidal α, β-unsaturated ketones (1-3). The products (4-6) were characterized by IR, (1)H NMR, (13)C NMR, MS and analytical data. The interaction studies of compounds (4-6) with DNA were carried out by employing gel electrophoresis, UV-vis and fluorescence spectroscopy.
Shams, Uzzaman, Ayaz Mahmood, Dar, Aamir, Sohail, Sheraz, Bhat, Mir Faisal, mustafa, Yusuf, Khan   +5 more
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MO study of molecular and electronic structure of 2H and 4H-pyrans

Collection of Czechoslovak Chemical Communications, 1981
CNDO/2, STO-3G and 4-31G MO calculations have been carried for the molecules I-IV. Their molecular and electronic structure is discussed with respect to relative stabilities of the respective compounds and valence isomerism I III. Significance of application of the split-valence base in the ab initio MO calculations carried out is demonstrated.
Josef Kuthan, Stanislav Böhm
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