Results 141 to 150 of about 14,631 (192)

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

Stereoselective synthesis of the pyran subunit of portentol

Organic & Biomolecular Chemistry
A concise synthesis of the pyran core of portentol was established in nine steps, involving an asymmetric lactate-anti-aldol reaction, selective lactol formation and a Corey–Winter elimination that proceeds with excellent diastereoselectivity.
Tan Hoang Luu, Florian Heppner, Johal Ruiz, Dirk Menche   +3 more
openaire   +2 more sources

Immunopharmacology of pyran copolymer

Pharmacological Research Communications, 1978
P, Puccetti, A, Giampietri
openaire   +2 more sources

Pyran derivatives

Il Farmaco, 2003
Mario Di Braccio, Giancarlo Grossi, Giorgio Roma, Cristina Marzano, Franca Baccichetti, Morena Simonato, Franco Bordin   +6 more
openaire   +1 more source

Investigation of positron scattering from 2H-pyran, 4H-pyran, and pyrrole molecules

Journal of Physics B: Atomic, Molecular and Optical Physics
Abstract The scattering cross-sections for positron-biomolecule interaction are an essential input for the Monte-Carlo simulation techniques. In the present work, we have reported the elastic integral, differential, momentum transfer, and total ionization cross-sections for scattering of positron from 2H-pyran, 4H-pyran, and pyrrole ...
Snigdha Sharma, Dhanoj Gupta
openaire   +1 more source