Results 101 to 110 of about 3,431 (233)

Addition of lithiated enol ethers to nitrones and subsequent Lewis acid induced cyclizations to enantiopure 3,6-dihydro-2H-pyrans – an approach to carbohydrate mimetics

Beilstein Journal of Organic Chemistry, 2010
A stereodivergent synthesis of enantiopure 3,6-dihydro-2H-pyrans is presented. The addition of lithiated enol ethers to carbohydrate-derived nitrones afforded syn- or anti-configured hydroxylamine derivatives 4a–d that were cyclized under Lewis acidic ...
Fabian Pfrengle, Hans-Ulrich Reissig
doaj   +1 more source

Photochromic carbazole photoinitiators for precision visible‐light photopolymerization

Polymer International, Volume 75, Issue 8, Page 722-728, August 2026.
New carbazole–naphthopyran derivatives were employed as visible‐light‐activated photoinitiators, enabling rapid and localized radical photopolymerization to produce well‐defined thin solid objects within minutes. Abstract Two carbazole derivatives, each incorporating a naphthopyran unit and an aromatic ketone, were synthesized and evaluated as ...
Mauro Magalhães, Céu M Sousa, José R Fernandes, Paulo J Coelho   +3 more
wiley   +1 more source

Enantioselective synthesis of mono- and disubstituted 3,6-dihydro-2H-pyrans and 5, 6-dihydro pyran-2-ones. [PDF]

, 2003
An enantioselective synthesis of mono- and disubstituted 3,6-dihydro-2H-pyrans and 5,6-dihydropyran-2-ones was achieved via ring-closing olefin metathesis, employing Grubb's catalyst, and starting from ready available chiral building ...
IZZO, Irene, DEL GAUDIO, Pasquale, SQUITIERI M, Carmela Della Monica, Francesco De Riccardis, Pasquale Del Gaudio, Maria Squitieri, Squitieri, DELLA MONICA, Carmela, DE RICCARDIS, Francesco, Irene Izzo   +10 more
core   +2 more sources

Structure‐Controlled Cyclopentadithiophene Derived Non‐Fullerene Acceptors for Efficient Near‐Infrared Organic Photodetectors

Small, Volume 22, Issue 43, 3 August 2026.
This work demonstrates high‐performance solution‐processed NIR OPDs using DTP‐ and DTTP‐based NFAs (OC and SC), where donor‐core engineering enables tunable absorption and balanced optoelectronic properties; notably, DTP‐based devices achieve broad NIR response, low dark current, and high detectivity, highlighting their potential for advanced NIR ...
Jong‐Woon Ha, Jae‐Hyun Kim, Byoungwook Park, Honghyun Park, Sung Cheol Yoon, Jaebin Jeong, Seunghun Lee, Jaeil Park, Jun‐Gyu Choi, Seo‐Jin Ko, Seung‐Hoon Lee, Sungjun Park   +11 more
wiley   +1 more source

Stimulation of Antibody Formation by Pyran Copolymer

Experimental Biology and Medicine, 1970
SummaryPyran copolymer, administered with sheep red blood cells to mice, enhances the early rate of appearance of antibody-forming spleen cells. Although the cytotoxicity and pyrogenicity of pyran and bacterial endotoxins are similar, pyran, in contrast to endotoxin, does not trigger a nonspecific initiation of antibody formation; it only enhances ...
W, Braun, W, Regelson, Y, Yajima, M, Ishizuka   +3 more
openaire   +2 more sources

Resilience of floral scent emission after florivory

Plant Biology, Volume 28, Issue 5, Page 1491-1506, August 2026.
Florivory is thought to affect floral traits, impacting pollination. However, our data suggest a stability in post‐florivory scent emission, which may guarantee the maintenance of pollinator visitation regardless of florivory, indicating a resilience of natural systems with multiple and simultaneous interactions. Created in BioRender. Tunes, P.
P. Tunes, Y. Canaveze, S. R. Machado, S. Dötterl, E. Guimarães   +4 more
wiley   +1 more source

Organobase-catalyzed three-component reactions for the synthesis of 4H-2-aminopyrans, condensed pyrans and polysubstituted benzenes

Beilstein Journal of Organic Chemistry, 2014
Novel routes for the preparation of 2-amino-4H-pyran-3-carbonitrile 9, amino-arylbenzoic acid ester derivatives 13a,b, 2-aminotetrahydro-4H-chromene-3-carbonitrile 18, 3-amino-4-cyanotetrahydronaphthalene-2-carboxylic acid ester 26 and 4-amino-3,5 ...
Moustafa Sherief Moustafa, Saleh Mohammed Al-Mousawi, Maghraby Ali Selim, Ahmed Mohamed Mosallam, Mohamed Hilmy Elnagdi   +4 more
doaj   +1 more source

Reference Data 1H and 13C NMR chemical shift assignment of some 3H-naphtho [ 2,1-b ] pyrans [PDF]

, 1999
International audienceThe 1H and 13C NMR resonances of four 3H-naphtho[2,1-b]pyrans were completely and unambiguously assigned by a combination of homonuclear (gs-COSY), 1H-detected heteronuclear one-bond (gs-HMQC) and long-range (gs-HMBC) gradient ...
Campredon, Mylene, `, Faure, Robert, Demadrille, Renaud, Giusti, Gerard, Campredon, Mylene,, Moustrou, Corinne   +5 more
core   +1 more source

Stereoselective Synthesis of Pyrans from Epoxyalkenes: Dual Catalysis with Palladium and Brønsted Acid [PDF]

, 2018
We describe regio- and stereoselective cycloisomerizations of alcohols tethered to epoxyalkenes, to construct alkene-substituted pyrans. These transformations are best catalyzed by Pd­(PPh3)4 in the presence of phosphite ligands, and with ...
Noah A. Setterholm (5310182), Frank E. McDonald (2305969)   +1 more
core   +1 more source

5-Ureido-3,3-diphenyl-3H-naphtho[2,1-b]pyrans: Photoswitchable self-assembling architectures

International Journal of Photoenergy, 2004
5-Ureido-3,3-diphenyl-3H-naphtho[2,1-b]pyrans have been synthesized and their photochromic properties have been quantified using UV-Visible spectroscopy.
X. Sallenave, S. Delbaere, S. Ahmed, G. Vermeersch, J. L. Pozzo   +4 more
doaj   +1 more source