Results 31 to 40 of about 22,717 (244)

PRENYLATED XANTHONES FROM Rheedia acuminata [PDF]

Acta Amazonica, 1993
Pyranojacareubin; 1,5-dihydroxy-6',6'-dimethyl-2H-pyran(2',3':6,7) -6",6"-dim-ethyI-2H,4H-pyran(2",3":2,3)xanthone and a new xanthone l,6-dihydroxy-5-methoxy-6',6'-dim-ethyl-2H-pyran(2',3':3,2)-7-(3,3-dimethylprop-2-enyl)xanthone were isolated from the ...
Maria das G. B ZOGHBI, Patrícia D. de D. Β. LIMA, Maria do P. Socorro C. da CUNHA, Angelo da C. PINTO   +3 more
doaj   +1 more source

An overview of structure-based activity outcomes of pyran derivatives against Alzheimer’s disease

Saudi Pharmaceutical Journal, 2023
Pyran is a heterocyclic group containing oxygen that possesses a variety of pharmacological effects. Pyran is also one of the most prevalent structural subunits in natural products, such as xanthones, coumarins, flavonoids, benzopyrans, etc. Additionally
Faisal A. Almalki
doaj   +1 more source

Crystal structure of 4-(6-chloro-4-oxo-4H-chromen-3-yl)-2-methylamino-3-nitro-4H,5H-pyrano[3,2-c]chromen-5-one chloroform monosolvate

Acta Crystallographica Section E: Crystallographic Communications, 2015
In the title compound, C23H14Cl4N2O7, the pyran ring has an envelope conformation with the methine C atom as the flap. The chromene rings are almost planar (r.m.s.
Rajamani Raja, Subramani Kandhasamy, Paramasivam T. Perumal, A. SubbiahPandi   +3 more
doaj   +1 more source

Crystal structure of ethyl (2S)-9-methoxy-2-methyl-4-oxo-3,4,5,6-tetrahydro-2H- 2,6-methanobenzo[g][1,3,5]oxadiazocine-11-carboxylate

Acta Crystallographica Section E: Crystallographic Communications, 2015
In the title compound, C15H18N2O5, the methoxyphenyl ring makes a dihedral angle of 84.70 (12)° with the mean plane of the tetrahydropyrimidin-2(1H)-one ring.
A. Dhandapani, S. Manivarman, S. Subashchandrabose, B. Gunasekaran   +3 more
doaj   +1 more source

Single‐Step Fabrication of Smart 3D Microstructures Exploiting Naphthopyrans as Photoinitiators and Photochromic Molecules

Advanced Optical Materials, EarlyView.
Naphthopyran–benzophenone compounds can act simultaneously as photoinitiators and photochromic molecules for two‐photon polymerization. Using a single‐step process, liquid photoresist is encapsulated within polymerized 3D microstructures, preserving reversible UV–vis photochromism after fabrication.
João P. Leote, Artur Andrishak, Paulo J. Coelho, José R. Fernandes, Christian Maibohm, Jana B. Nieder   +5 more
wiley   +1 more source

Effects of Pyran-Ring Structure in Carbon Sources on the Electrochemical Performance of LiFePO4/C

International Journal of Electrochemical Science, 2013
Nano-sized LiFePO4/C (LFP/C) with excellent electrochemical performance was prepared by using carbon precursors with different pyran-ring structures as carbon sources.
Baohua Li, Yutao Xing, Xiaodong Chu, Jun Ma, Yan-Bing He, Dengyun Zhai, Hongda Du, Chunguang Wei, Hongzhou Chen, Feiyu Kang   +9 more
doaj   +1 more source

Dynamic Fluorescence Modulation via Light‐Driven Competitive Protonation

Advanced Optical Materials, EarlyView.
A two‐component molecular system demonstrates reversible, light‐driven fluorescence write–erase cycling and thermal imaging. Illumination of a merocyanine photoacid transfers a proton to a highly efficient fluorescent pyridinium dye, switching its emission color; thermal relaxation reverses the process in the dark.
Serena X. Liu, Moritz E. Kleybolte, Colin van Dyck, Sergey I. Vagin, Preeti Gahtori, Antonio Scarpati, Razieh Firouzihaji, Diogo A. Galico, Ulrich S. Schubert, Julianne Gibbs, Alkiviathes Meldrum   +10 more
wiley   +1 more source

Diastereoselective synthesis of 3,4-dihydro-2H-pyran-4-carboxamides through an unusual regiospecific quasi-hydrolysis of a cyano group

Beilstein Journal of Organic Chemistry, 2016
An efficient diastereoselective approach for the synthesis of functionalized 3,4-dihydro-2H-pyran-4-carboxamides with variable frame was developed based on the reaction of available 4-oxoalkane-1,1,2,2-tetracarbonitriles (adducts of TCNE and ketones ...
Mikhail Yu. Ievlev, Oleg V. Ershov, Mikhail Yu. Belikov, Angelina G. Milovidova, Viktor A. Tafeenko, Oleg E. Nasakin   +5 more
doaj   +1 more source

PRENYLATED XANTHONES FROM Rheedia acuminata (reprinted from Acta Amazônica, 23(2/3):181-185) [PDF]

Acta Amazonica, 1994
Pyranojacareubin; 1,5-dihydroxy-6',6'-dimethyl-2H-pyran(2,,3':6,7) -6",6"-dime-thyl-2H,4H-pyran(2",3":2,3)xanthone and a new xanthone l,6-dihydroxy-5-methoxy-6',6'-dime-thyl-2H-pyran(2',3':3,2)-7-(3,3-dimethylprop-2-enyl)xanthone were isolated from the ...
Maria das G. B. ZOGHBI, Patrícia D. de D. B. LIMA, Maria do P. Socorro C. da CUNHA, Angelo da C. PINTO   +3 more
doaj   +1 more source

Purely Equatorial Lasing in Spherical Liquid Crystal Polymer Microlasers with Bipolar Refractive Index Profile

Advanced Optical Materials, EarlyView.
Spherical liquid crystal polymer microlasers with a bipolar configuration confine lasing to a single equatorial plane, allowing precise control over where the laser emission is generated. The anisotropic refractive index profile additionally lifts the energy degeneracy of azimuthal whispering gallery modes, which causes a characteristic splitting into ...
David Ripp, Nachiket Pathak, Vera M. Titze, Catriona A. Thomson, Andreas Mischok, Marcel Schubert   +5 more
wiley   +1 more source