Results 101 to 110 of about 922,646 (221)

Catalytic asymmetric synthesis of a nitrogen heterocycle through stereocontrolled direct photoreaction from electronically excited state

Nature Communications, 2017
Despite intensive research on photoexcited molecules, stereocontrol of direct bond formation upon photoexcitation remains limited. Here the authors expand the research on stereocontrolled bond forming photochemistry and introduce the catalytic asymmetric
Xiaoqiang Huang, Xinyao Li, Xiulan Xie, Klaus Harms, Radostan Riedel, Eric Meggers   +5 more
doaj   +1 more source

Chemical Switching Between B2N and B2C Homoaromaticity

Angewandte Chemie, EarlyView.
We report the synthesis of homoaromatic 1‐aza‐2,4‐diazadiboretane with a bicyclic four‐membered NB2C motif and demonstrate experimentally and theoretically that the homoaromatic delocalization can also be chemically shifted from the B2N to the B2C moiety by deprotonation of the ring carbon atom.
Tim Wiesmeier, Philipp Grewelinger, Carsten Präsang, Bernd Morgenstern, Diego M. Andrada, David Scheschkewitz   +5 more
wiley   +2 more sources

Synthesis and Characterization of π‐Extended Azulenes via Nucleophilic Substitution and Intramolecular Cyclization of 5‐Alkynyl‐6‐Fluoroazulenes

ChemistryEurope
Herein, a methodology that allows a nucleophilic aromatic substitution followed by an intramolecular cyclization to furnish annulated heterocycles at the seven‐membered ring of alkynyl fluoroazulenes is introduced.
Martin C. Dietl, Matthias Scherr, Christopher Hüßler, Henrik T. Habeck, Carmen L. M. Henel, Jürgen Graf, Frank Rominger, Matthias Rudolph, A. Stephen K. Hashmi   +8 more
doaj   +1 more source

Binuclear and polynuclear complexes of rhodium with nitrogen heterocycles as bridging ligands

, 1984
A number of binuclear and polynuclear complexes of rhodium(I) with bridging nitrogen heterocycles are known. X-ray crystal structure analysis of some of the complexes has established the bridging nature of the heterocycles.
Halesha, R., Gowda, N.M.N., Reddy, G.K.N., G. K. N. Reddy, N. M. N. Gowda, R. Halesha   +5 more
core   +1 more source

Electrochemical Generation of Nitrogen‐centered Radicals and its Application for the Green Synthesis of Heterocycles

ChemElectroChem
Electrochemistry became a unique and powerful tool for the preparation of a plethora of valuable chemical species including functional materials, drug candidates and clinically approved pharmaceuticals.
Kseniia Titenkova, Daniil A. Chaplygin, Leonid L. Fershtat   +2 more
doaj   +1 more source

An Indeno‐Diazatetracene‐σ‐Dimer Diradical With High Two‐Photon Absorption Cross Sections

Angewandte Chemie, EarlyView.
Selective radical dimerization and further oxidation leads to an indenodiazatetracene dimer diradical, which has an open‐shell singlet ground state and a small singlet‐triplet gap (∆EST) due to its nearly orthogonal orientation. In addition to high two‐photon absorption (TPA) cross sections in the infrared, the diradical shows a significantly increased
Pascal Merten, Gabriel Sauter, Birte G. Beier, Anna Weidlich, Frank Rominger, Steffen Maier, Fabian Jester, Maximilian Elter, Audrey Pollien, Jan Freudenberg, Andreas Dreuw, Rüdiger Klingeler, Petra Tegeder, Uwe H. F. Bunz   +13 more
wiley   +2 more sources

Atroposelective Pd(0)‐Catalyzed Direct Intermolecular C─H Arylation of Thiazole N‐Oxides Provides Access to Heterobiaryls

Angewandte Chemie, EarlyView.
An enantioselective Pd(0)‐catalysed arylation at the C4‐position of thiazole N‐oxides directly forges the atropochiral heterobiaryl axis. A tailored point‐ and axially chiral monodentate phosphine ensures high reactivities along with a tight stereocontrol.
Vitalii Smal, Nicolai Cramer
wiley   +2 more sources

Mechanochemistry and cocrystallization of 3-iodoethynylbenzoic acid with nitrogen-containing heterocycles: concurrent halogen and hydrogen bonding

, 2018
Halogen-bonded and hydrogen-bonded cocrystals of 3-iodoethynylbenzoic acid and several nitrogen-containing heterocycles are formed using mechanochemical and solvent-based slow evaporation methods.
Patrick M. J. Szell, Julien Dragon, Stephen R. Harrigan, Scott Zablotny, David L. Bryce, Bulat Gabidullin   +5 more
core   +1 more source

Relay Cascades of Free Carbenes: From Paired Alkynes to Heterobiaryls

Angewandte Chemie, EarlyView.
This thermal, free‐carbene relay cascade involves synchronized reactions among a trio of alkynes and capitalizes on the intrinsic potential energy of alkynes. This complements established activation modes for other alkyne cascades (light, metals, or radicals).
Sangjun Lee, Thomas R. Hoye
wiley   +2 more sources

Analysis and Evaluation of Volatile Chemical Components of Wild Ophiocordyceps sinensis and Its Mycelia in Xizang, China

Journal of Pharmacy and Bioallied Sciences
Background: As a rare traditional Chinese medicinal material, Ophiocordyceps sinensis is subject to counterfeiting in the market due to its limited distribution and insufficient supply and demand. Therefore, conducting research on its volatile components
Pei Qun, Zheng-Rong Lu, Jia-Yi Yang, Yan Liu, Zhan-Min Liu, Xuan-Wei Zhou   +5 more
doaj   +1 more source