Results 21 to 30 of about 49,972 (158)

Regioselectivity of the SEAr-based cyclizations and SEAr-terminated annulations of 3,5-unsubstituted, 4-substituted indoles

Beilstein Journal of Organic Chemistry, 2022
Indole-3,4- and 4,5-fused carbo- and heterocycles are ubiquitous in bioactive natural products and pharmaceuticals, and hence, a variety of synthetic approaches toward such compounds have been developed.
Jonali Das, Sajal Kumar Das
doaj   +1 more source

Quantitative analysis of cytokinesis in situ during C. elegans postembryonic development. [PDF]

PLoS ONE, 2014
The physical separation of a cell into two daughter cells during cytokinesis requires cell-intrinsic shape changes driven by a contractile ring. However, in vivo, cells interact with their environment, which includes other cells.
Karine G Bourdages, Benjamin Lacroix, Jonas F Dorn, Carlos P Descovich, Amy S Maddox   +4 more
doaj   +1 more source

Synthesis of 2,3,6,7-tetrabromoanthracene

Beilstein Journal of Organic Chemistry, 2008
The first synthesis of 2,3,6,7-tetrabromoanthracene is presented, starting from benzene in a straightforward four step synthesis.
Christian Schäfer, Friederike Herrmann, Jochen Mattay   +2 more
doaj   +1 more source

DFT calculations on the mechanism of copper-catalysed tandem arylation–cyclisation reactions of alkynes and diaryliodonium salts

Beilstein Journal of Organic Chemistry, 2018
We present a computational mechanistic study on the copper(III)-catalysed carboarylation–ring closure reactions leading to the formation of functionalised heterocycles.
Tamás Károly Stenczel, Ádám Sinai, Zoltán Novák, András Stirling   +3 more
doaj   +1 more source

Photo-induced copper-catalyzed sequential 1,n-HAT enabling the formation of cyclobutanols

Nature Communications, 2021
Cyclobutanols are difficult structures to access given their inherent ring strain. Here, the authors present a method to form substituted cyclobutanols from a photocatalytic cascade reaction, proceeding via a 1,5- or 1,6-hydrogen atom transfer and ...
Zhusong Cao, Jianye Li, Guozhu Zhang
doaj   +1 more source

Microwave-assisted ring closure reactions: Synthesis of 8-substituted xanthine derivatives and related pyrimido- and diazepinopurinediones

Beilstein Journal of Organic Chemistry, 2006
BackgroundPoly-substituted xanthine derivatives are an important class of compounds in medicinal chemistry. Substitution at the 8-position of the purine ring is generally accessible by ring closure of a carboxamido-substituted uracil precursor.
Joachim C. Burbiel, Jörg Hockemeyer, Christa E. Müller   +2 more
doaj   +1 more source

On the algebraic closure in rings [PDF]

Proceedings of the American Mathematical Society, 2007
Soit \(A\) un anneau unifère et \(A^{-1}\) le groupe de ses éléments inversibles. On désigne par \(d(K)\) la clôture algébrique d'une partie \(K\) de \(A\) l'ensemble des éléments \(a\) de \(A\) tels que, pour tout élément \(b\) de \(A\) il existe un élément \(a'\) de \(K\) tel que \(1-b(a-a')\) appartienne à \(A^{-1}\). Les AA.
Cvetkovic-Ilic, Dragana, Harte, Robin
openaire   +1 more source

Blocking-cyclization technique for precise synthesis of cyclic polymers with regulated topology

Nature Communications, 2018
Cyclic polymers can be usually accessed by ring-expansion and ring-closure approaches. Here, the authors report an alternative blocking-cyclization technique which enables the tunable synthesis of multicyclic polymers via commercial Ru-based Grubbs ...
Jie Chen, Hongfei Li, Hengchen Zhang, Xiaojuan Liao, Huijing Han, Lidong Zhang, Ruyi Sun, Meiran Xie   +7 more
doaj   +1 more source

Benzoxetes and Benzothietes ¾ Heterocyclic Analogues of Benzocyclobutene

Molecules, 2012
Benzo-condensed four-ring heterocycles, such as benzoxetes 1 and benzothietes 3 represent multi-purpose starting compounds for the preparation of various higher heterocyclic ring systems.
Herbert Meier
doaj   +1 more source

Synthesis of Substituted 2-Benzoylaminothiobenzamides and Their Ring Closure to Substituted 2-Phenylquinazoline-4-thiones

Molecules, 2001
Acylation of 2-aminothiobenzamide or 2-methylaminothiobenzamide with substituted benzoyl chlorides has been used to synthesise the corresponding 2-benzoylaminothiobenzamides whose subsequent sodium methoxide-catalysed ring closure gives the corresponding
MiloÅ¡ Sedlák, Lenka Kubicová, Ludmila Hejtmánková, Jiří Hanusek   +3 more
doaj   +1 more source