Results 21 to 30 of about 158,943 (323)

Synthesis of New C-3 Substituted Kynurenic Acid Derivatives

Molecules, 2020
The application of kynurenic acid (KYNA) as an electron-rich aromatic system in the modified Mannich reaction has been examined. The extension possibility of the reaction was tested by using amines occurring in a number of bioactive products, such as ...
Bálint Lőrinczi, Antal Csámpai, Ferenc Fülöp, István Szatmári   +3 more
doaj   +1 more source

Substrate control in stereoselective lanthionine biosynthesis. [PDF]

, 2015
Enzymes are typically highly stereoselective catalysts that enforce a reactive conformation on their native substrates. We report here a rare example in which the substrate controls the stereoselectivity of an enzyme-catalysed Michael-type addition ...
Houk, KN, Jiménez-Osés, Gonzalo, Tang, Weixin, van der Donk, Wilfred A   +3 more
core   +4 more sources

Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic dienes

Beilstein Journal of Organic Chemistry, 2021
The Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic 1,3-dienes was investigated. A series of novel monofluorinated norbornenes was prepared in up to 97% yield.
Savva A. Ponomarev, Roman V. Larkovich, Alexander S. Aldoshin, Andrey A. Tabolin, Sema L. Ioffe, Jonathan Groß, Till Opatz, Valentine G. Nenajdenko   +7 more
doaj   +1 more source

Solvent-Free C-3 Coupling of Azaindoles with Cyclic Imines

Molecules, 2019
By direct coupling 7-azaindole and cyclic imines, such as 3,4-dihydroisoquinoline, 6,7-dihydrothieno[3,2-c]pyridine, 3,4-dihydro-β-carboline, and 4,5-dihydro-3H-benz[c]azepine, new 3-substituted 7-azaindole derivatives have been synthesized.
Khadija Belasri, Ferenc Fülöp, István Szatmári   +2 more
doaj   +1 more source

Nucleophilic Substitution at Heteroatoms—Identity Substitution Reactions at Phosphorus and Sulfur Centers: Do They Proceed in a Concerted (S_N2) or Stepwise (A–E) Way?

Molecules, 2022
The mechanisms of three selected identity substitution reactions at phosphorus and sulfur occurring with stereospecific inversion have been investigated using density functional theory (DFT).
Marian Mikołajczyk, Marek Cypryk, Bartłomiej Gostyński, Jakub Kowalczewski   +3 more
doaj   +1 more source

Synthesis of cyclopropanes via organoiron methodology: stereoselective preparation of cis-2-(2’-carboxycyclopropyl)glycine [PDF]

, 2002
A stereoselective route to cis-2-(2′-carboxycyclopropyl)glycine has been developed. exo-Nucleophilic addition to the (bicyclo[5.1.0]octadienyl)iron(1+) cation establishes the relative stereochemistry at the cyclopropane ring and the α-stereocenter ...
Donaldson, William, Wallock, Nathaniel J
core   +2 more sources

Synthesis, Enantiomeric Resolution and Biological Evaluation of HIV Capsid Inhibition Activity for Racemic, (S)- and (R)-PF74

Molecules, 2021
PF74 is a capsid-targeting inhibitor of HIV replication that effectively perturbs the highly sensitive viral uncoating process. A lack of information regarding the optical purity (enantiomeric excess) of the single stereogenic centre of PF74 has resulted
Stuart Ruddell, Elena Sugrue, Sarah Memarzadeh, Lorna Mae Hellam, Sam J. Wilson, David J. France   +5 more
doaj   +1 more source

Stereo-Aware Extension of HOSE Codes [PDF]

, 2019
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Descriptions of molecular environments have many applications in chemoinformatics, including chemical shift
Johnson, Sean R., Kuhn, Stefan
core   +1 more source

X-ray Diffraction, Electronic Circular Dichroism, and Quantum Mechanics (TD-DFT) Investigations on 4 Dehydroxyaltersolanol A, a Secondary Metabolite from Endophytic Fungus Nigrospora oryzae [PDF]

Research Journal of Pharmacognosy
Background and objectives: A tetrahydro anthraquinone derivative, 4-dehydroxyaltersolanol A, has been obtained from Nigrospora oryzae, which was isolated from Uncaria borneensis Havil as an endophytic fungus.
Fatimah Bebe Mohamed Hussain, Sadia Sultan*, Imene Bayach, Humera Naz, Gurmeet Kaur Surindar Singh, Syed Adnan Ali Shah, Kamran Ashraf, Fatimah Saleem, Jean-Frédéric Faizal Weber   +8 more
doaj   +1 more source

Electron Lone-Pairs Stereochemistry and Drastic van der Waals and Pressure Effects in AsF₃ from First Principles

Condensed Matter, 2021
AsF3E as a representative of a molecular crystal has been chosen to find the precise localization of the lone pair (LP) E centroid 4s2 of As3+ and to enlighten the behavior of lone pair triplets of fluorine atoms. Starting from stereochemistry rationale,
Jean Galy, Samir F. Matar
doaj   +1 more source