Results 131 to 140 of about 2,222 (186)

2H-pyrans (review)

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, A. D. Garnovskii, A. V. Kazantsev   +2 more
openaire   +1 more source

Strategies for the synthesis of bioactive pyran naphthoquinones

Organic & Biomolecular Chemistry, 2010
Taking into account the numerous reports in the literature related to pyran naphthoquinones in searching for new pharmacologically promising molecules against different therapeutic targets, this review intends to explore the synthetic methodologies for preparing these bioactive compounds.
Vitor Francisco, Ferreira, Sabrina Baptista, Ferreira, Fernando de Carvalho, da Silva   +2 more
openaire   +2 more sources

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
openaire   +1 more source

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
openaire   +1 more source

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
openaire   +1 more source

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
openaire   +2 more sources

Asymmetric Synthesis of the Pyran Antibiotic (‐)‐Centrolobine.

ChemInform, 2005
An expedient total synthesis of (−)-centrolobine is achieved involving asymmetric Keck allylation and stereoselective intramolecular oxy-Michael reactions as key steps in 8% overall yield.
S. Chandrasekhar, S. Jaya Prakash, T. Shyamsunder   +2 more
openaire   +1 more source

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
openaire   +2 more sources

ChemInform Abstract: ACTIVATED NITRILES IN HETEROCYCLIC CHEMISTRY: A NOVEL SYNTHESIS OF PYRANS, PYRIDONES, PYRAZOLO(4,3‐B)PYRANS AND ISOXAZOLO(4,3‐B)PYRANS

Chemischer Informationsdienst, 1984
AbstractDie Verbindungen (I) reagieren mit CH‐aciden Verbindungen (II) unter Bildung der Pyridone (III).
M. A. E. KHALIFA, G. H. TAMMAM, A. A. A. ELBANANY   +2 more
openaire   +1 more source

Pyrans, Thiopyrans, and Selenopyrans

1983
Publisher Summary This chapter presents the literature for pyrans, thiopyrans, and selenopyrans. Pyran structure refers to a six-membered ring possessing one oxygen, sulfur, selenium, or telurium heteroatom singly bonded in a cyclic system of two double bonds and one tetrahedral atomic center.
openaire   +1 more source