Results 111 to 120 of about 169,803 (413)

Is ESA Relationship The Tool In Searching For Interstellar Heterocycles? [PDF]

arXiv, 2019
Because of their importance in biological systems, in our understanding of the solar system and in other applications, seven heterocycles; furan, imidazole, pyridine, pyrimidine, pyrrole, quinoline and isoquinoline have been astronomically searched for in different molecular clouds with only the upper limits in the range of 4*1012 to 2.8*1021cm-2 ...
arxiv  

Continuous Flow Synthesis of α‐Chloroketones from Esters

Advanced Synthesis &Catalysis, EarlyView.
Abstract Herein, we report a novel and practical strategy to access α‐chloroketones from esters bearing diverse (hetero)aromatic, aliphatic, alkynyl and alkenyl substituents with transient chloromethyllithium under continuous flow conditions. This highly chemoselective method enables a fast (on a time scale of <5 s), efficient and straightforward ...
Léna Brassart, Maxime Manneveau, Thomas Poisson, Julien Legros, Philippe Huez, Massimiliano Forcato, Philippe Jubault, Laëtitia Chausset‐Boissarie   +7 more
wiley   +1 more source

Genome Mining Enabled by Biosynthetic Characterization Uncovers a Class of Benzoxazolinate‐Containing Natural Products in Diverse Bacteria

Angewandte Chemie, Volume 134, Issue 51, December 19, 2022., 2022
Benzoxazolinate is a rare bis‐heterocyclic moiety that interacts with proteins and DNA. It was found that a putative acyl AMP‐ligase mediates the last cyclization step to afford benzoxazolinate. The enzyme was then used as a probe for genome mining, which led to the discovery of a new class of benzoxazolinate‐containing compounds in diverse bacteria ...
Yi‐Ming Shi, Jan J. Crames, Laura Czech, Kenan A. J. Bozhüyük, Yan‐Ni Shi, Merle Hirschmann, Stefanie Lamberth, Peter Claus, Nicole Paczia, Christian Rückert, Jörn Kalinowski, Gert Bange, Helge B. Bode   +12 more
wiley   +2 more sources

Divergent synthesis of N-heterocycles via controllable cyclization of azido-diynes catalyzed by copper and gold

Nature Communications, 2017
Fused N-heterocycles are structural motifs observed in natural products and bioactive compounds. Here, the authors developed divergent copper- and gold-catalyzed oxidative cyclizations of diynes to two types of tricyclic N-heterocycles and rationalized ...
Wen-Bo Shen, Qing Sun, Long Li, Xin Liu, Bo Zhou, Juan-Zhu Yan, Xin Lu, Long-Wu Ye   +7 more
doaj   +1 more source

Synthesis of Unnatural Amino Acids via β‐Aminoaldehyde C–H Arylation using HAT‐Metallaphotoredox Catalysis

Advanced Synthesis &Catalysis, EarlyView.
Abstract Unnatural amino acids play a crucial role in advancing protein engineering and drug development. In this study, we present the synthesis of a series of γ‐aryl‐keto‐α‐amino acids through the direct C−H arylation of readily accessible β‐aminoaldehydes and aryl bromides, promoted by hydrogen atom transfer combined with metallaphotoredox catalysis.
Mariana dos S. Dupim, Bruno M. da S. Santos, Lívia C. R. M. da Frota, Fernanda G. Finelli   +3 more
wiley   +1 more source

Temperature‐ and pH‐Responsive Polymeric Photocatalysts for Enhanced Control and Recovery

Angewandte Chemie, Volume 134, Issue 51, December 19, 2022., 2022
Stimuli‐responsive photocatalytic materials have emerged that are not only able to efficiently catalyze reactions but can use external stimuli to modulate their physical properties. This technique has been used to control the reactivity of a photocatalytic material turning it on/off. Moreover, photocatalytic materials have been synthesized which can be
Rong Li, Katharina Landfester, Calum T. J. Ferguson   +2 more
wiley   +2 more sources

Stereoselectively fluorinated N-heterocycles: a brief survey

Beilstein Journal of Organic Chemistry, 2013
The stereoselective incorporation of fluorine atoms into N-heterocycles can lead to dramatic changes in the molecules’ physical and chemical properties.
Xiang-Guo Hu, Luke Hunter
doaj   +1 more source

Vinylogous aldol reaction of heterocyclic silyloxy dienes. Application in synthesis [PDF]

, 2000
A versatile, readily accessible triad of 2-enoxy silane synthons derived from furan, pyrrole, and thiophene is presented. These heterocycles, in reacting with carbonyl and carbonyl- related acceptors, act as vinylogous nucleophile modules, giving rise ...
Casiraghi, Giovanni, Rassu, Gloria Maria Rita, Zanardi, Franca   +2 more
core  

(Phosphanyl)phosphaketenes as building blocks for novel phosphorus heterocycles. [PDF]

, 2017
Although BH3 simply coordinates the endocyclic P of (phospholidino)phosphaketene 1Dipp , the bulkier B(C6F5)3 gives rise to a zwitterionic diphosphirenium, which is a novel type of 2π-electron aromatic system as shown by the calculated NICS values. While
Bertrand, Guy, Hansmann, Max M, Jazzar, Rodolphe, Liu, Liu Leo, Ruiz, David A   +4 more
core   +2 more sources

Tunable Preparation of β‐Substituted Alkenoate Esters via Radical Alkenylation of C(sp3)–H Bonds with Allenoates

Advanced Synthesis &Catalysis, EarlyView.
Abstract A photocatalytic strategy for the radical alkenylation of aliphatic C(sp3)–H bonds with 2,3‐allenoate esters is described. The protocol takes place upon irradiation of the reaction mixture in the presence of the decatungstate anion, which triggers C−H cleavage in the chosen aliphatic substrates.
Alexandra Jorea, Roberto Chessa, Davide Ravelli   +2 more
wiley   +1 more source