Results 61 to 70 of about 3,431 (233)

Palladium(II)-Catalyzed Intramolecular 1,4-Oxyacyloxylation of Conjugated Dienes. A Stereocontrolled Route to Fused Six-Membered Lactones and Pyrans [PDF]

, 2016
Stereocontrolled palladium(II)-catalyzed intramolecular 1,4-oxidations of dienyl acids and alcohols proceed under mild conditions to give fused δ-lactones and pyrans, respectively, in good yields.
B. Anders Persson (2718820), Jan-E. Bäckvall (2466835), Renzo C. Verboom (2718817)   +2 more
core   +1 more source

Modeling Pyran Formation in the Molybdenum Cofactor: Protonation of Quinoxalyl–Dithiolene Promoting Pyran Cyclization [PDF]

Inorganic Chemistry, 2019
Mononuclear Mo and W enzymes require a unique ligand known as molybdopterin (MPT). This ligand binds the metal through a dithiolene chelate, and the dithiolene bridges a reduced pyranopterin group. Pyran scission and formation have been proposed as a reaction of the MPT ligand that may occur within the enzymes to adjust reactivity at the Mo atom.
Douglas R. Gisewhite, Alexandra L. Nagelski, Daniel C. Cummins, Glenn P. A. Yap, Sharon J. N. Burgmayer   +4 more
openaire   +2 more sources

Plasmepsins as Antimalarial Drug Targets—Then, Now, and the Future

Medicinal Research Reviews, EarlyView.
ABSTRACT Malaria is a devastating disease caused by Plasmodium parasites. Plasmodium parasites express ten cathepsin D‐like aspartyl proteases, called plasmepsins (PMs). These PMs have diverse roles fulfill diverse functions throughout the parasite's lifecycle, though several exhibit functional redundancies. Among them, PMV, PMIV, and PMX are essential
Brad E. Sleebs
wiley   +1 more source

An Ab Initio Molecular Orbital Study of the Conformational Energies of 2-Alkyltetrahydro-2H-Pyrans (Tetrahydropyrans, Oxacyclohexanes, Oxanes) [PDF]

, 2000
Ab initio Hartree-Fock and Density Functional Theory calculations were used to obtain the geometries and relative energies of the rotamers in the chair conformations of 2-alkyltetrahydro-2H-pyrans and 2- (trimethylsilyl)tetrahydro-2H-pyran. The MP2/6-31G*
Kasner, Marc, Hehre, Warren J., Freeman, Fillmore, Kasner, J. A.   +3 more
core   +1 more source

Green chemistry preparation of MgO grit like nanostructures: efficient catalyst for the synthesis of 4H-pyrans and α,α′-bis(substituted-benzylidene) cycloalkanone derivatives

Green Processing and Synthesis, 2016
A grit like nanostructure of MgO was prepared in a medium of mulberry leaves extract and characterized on the basis of field emission scanning electronic microscopy (FE-SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) analysis.
Mobinikhaledi Akbar, Yazdanipour Atisa, Ghashang Majid   +2 more
doaj   +1 more source

Organocatalysis in Synthesis: L-Proline as an Enantioselective Catalyst in the Synthesis of Pyrans and Thiopyrans

Molecules, 2012
The multicomponent reaction (MCR) of aromatic aldehydes 1 and malononitrile (2) with active methylenes 5a–h in the presence of L-proline produced pyrans and thiopyrans 6a–h stereospecifically and in good yields.
Noura Saad Al-Hokbany, Noha M. Hilmy Elnagdi   +1 more
doaj   +1 more source

The continuing significance of chiral agrochemicals

Pest Management Science, Volume 81, Issue 4, Page 1697-1716, April 2025.
In the time frame 2018–2023, around 43% of the 35 chiral agrochemicals introduced to the market (herbicides, fungicides, insecticides, acaricides, and nematicides) contain one or more stereogenic centers in the molecule, and almost 69% of them have been marketed as racemic mixtures of enantiomers or stereoisomers.
Peter Jeschke
wiley   +1 more source

α-Alkoxystannanes as masked oxonium ions: application to the synthesis of furo[2,3-b]pyrans [PDF]

, 2006
α-Alkoxystannanes undergo oxidation upon treatment with cerium ammonium nitrate generating oxonium ions, which can be trapped in an intramolecular fashion affording furo[2,3-b]pyrans. © 2006 Elsevier Ltd.
Peter Quayle, Mills, Keith, Wang, Shouming, Gilbert, Philip S., Shouming Wang, Simon P. Thompson, Philip S. Gilbert, Michael R. Attwood, Lewis, Mark L., Thompson, Simon P., Attwood, Michael R., Quayle, Peter, Mark L. Lewis, Keith Mills   +13 more
core   +1 more source

Ultrasound-assisted multicomponent synthesis of 4H-pyrans in water and DNA binding studies [PDF]

, 2020
A simple approach to synthesize new highly substituted 4H-pyran derivatives is described. Efficient Et3N acts as a readily accessible catalyst of this process performed in pure water and with only a 20 mol% of catalyst loading.
Fernández-Moreira, Vanesa, Marqués-López, Eugenia, Pérez Herrera, Raquel, Gimeno, M. Concepción, Auria-Luna, Fernando, Herrera, Raquel P.   +5 more
core   +1 more source

Relaxant Activity of 4H-Pyran and 1,6-Dihydropyridine Derivatives on Isolated Rat Trachea

Drugs and Drug Candidates
Derivatives of 4H-pyrans and 1,6-dihydropyridines have generated considerable attention due to their interesting biological and therapeutic values. Their pharmacological activities include vasorelaxant, anticarcinogenic, antimicrobial, and antioxidant ...
Samuel Estrada-Soto, Soledad Alemán-Pantitlán, Emmanuel Gaona-Tovar, Fernando Hernández-Borja, Yolanda Alcaraz, Rafael Villalobos-Molina, Miguel A. Vázquez   +6 more
doaj   +1 more source