Results 41 to 50 of about 35,698 (262)

Excited States Symmetry Breaking and In-Plane Polarization Cause Chiral Reversal in Diastereomers

Molecules, 2021
In this work, we investigate the electronic transitions and chirality of three isomers of huge conjugated systems: asymmetric diastereomers (MMMM) and two symmetrical diastereomers (PMPM and PPMM).
Chenglong Wang, Jingang Wang, Chunyang Wang   +2 more
doaj   +1 more source

Discovery of macrocyclic inhibitors of apurinic/apyrimidinic endonuclease 1 [PDF]

, 2019
Apurinic/apyrimidinic endonuclease 1 (APE1) is an essential base excision repair enzyme that is upregulated in a number of cancers, contributes to resistance of tumors treated with DNA-alkylating or -oxidizing agents, and has recently been identified as ...
Beglov, Dmitri, Brown, Lauren E., Chen, Qiujia, Chennamadhavuni, Spandan, Georgiadis, Millie M., He, Hongzhen, Kelley, Mark R., Panek, James S., Porco, John A., Reed, April, Trilles, Richard, Vajda, Sandor, Wireman, Randall   +12 more
core   +7 more sources

Strategies Toward Accessing Enantioenriched (Hetero)Benzo‐Fused 5‐ and 6‐ Membered Rings via Intermolecular Carbometalation

Angewandte Chemie, EarlyView.
The use of transition‐metal catalysts and design of chiral ligands have allowed chemists to access highly functionalized benzofused 5‐ and 6‐ membered rings in high yield and enantioselectivity. A common strategy used relies on an intermolecular carbometalation across alkynes and olefins, usually followed by a subsequent intramolecular carbometalation.
Clara Jans, Armaan Grewal, Xavier Abel‐Snape, Mark Lautens   +3 more
wiley   +2 more sources

The Synthesis of a Bis(thiosemicarbazone) Macrocyclic Ligand and the Mn(II), Co(II), Zn(II) and ⁶⁸Ga(III) Complexes

Molecules, 2021
A 1,4,7,10-tetraazacyclododecane (cyclen) variant bearing two thiosemicarbazone pendant groups has been prepared. The ligand forms complexes with Mn2+, Co2+ and Zn2+.
Melyssa L. Grieve, Patrick R. W. J. Davey, Craig M. Forsyth, Brett M. Paterson   +3 more
doaj   +1 more source

X=Y–ZH compounds as potential 1,3-dipoles. Part 64: Synthesis of highly substituted conformationally restricted and spiro nitropyrrolidines via Ag(I) catalysed azomethine ylide cycloadditions [PDF]

, 2008
1,3-Dipolar reactions of imines of both acyclic and cyclic α-amino esters with a range of nitroolefins using a combination of AgOAc or Ag2O with NEt3 are described.
Albert, Amornraksa, Ayerbe, Becker, Berger, Bourguignon, Bryce, Cecilia Orgaz de la Cierva, Colin Kilner, Crooks, Dondas, Díaz-Ortiz, Fejes, Fejes, Gentles, Grigg, Grigg, Grigg, Grigg, Grigg, Grigg, Grigg, Grigg, Grigg, H. Ali Dondas, Hill, Kabalka, Krapcho, Lee, Mohammed A.B. Sarker, Nielson, Norman, Nyerges, Nyerges, Nyerges, Nyerges, Nyerges, Pak, Peterli, Pinna, Poornachandran, Poornachandran, Poornachandran, Ram, Rang, Ronald Grigg, Sader-Bakaouni, Shorter, Song, Thurkauf, Vivanco, Yan   +51 more
core   +1 more source

A Revised Model for Muscarine Biosynthesis Involving Lysine Trimethylation

Angewandte Chemie, EarlyView.
The fatal mushroom toxin l‐(+)‐muscarine is one of the most prominent natural products. We elucidated its biosynthetic origin in the sweating mushroom Collybia rivulosa based on incorporation of stable isotope‐labeled compounds and extensive mass spectrometric analyses.
Sebastian Dörner, Kai Rogge, Felix Trottmann, Christian Hertweck, Dirk Hoffmeister   +4 more
wiley   +2 more sources

Aldehyde–Olefin Couplings by Photoinduced Reduction of Electron‐Deficient Olefins with Hantzsch Ester Anions

Angewandte Chemie, EarlyView.
Single‐electron transfer‐mediated reductive carbonyl–olefin couplings are valuable carbon–carbon bond forming reactions. However, limitations persist for couplings of aliphatic aldehydes with electron‐deficient olefins. Here, we report a simple, photocatalyst‐free protocol that overcomes these limitations by using a Hantzsch ester anion as a ...
Zhihang Li, Adam Noble
wiley   +2 more sources

Analysis of cis-isomer-enriched dihydroquercetin sample by 1D and 2D NMR spectroscopy

Разработка и регистрация лекарственных средств
Introduction. The structure of dihydroquercetin (DHQ) is characterized by two chiral centers at positions 2 and 3 of the benzopyran cycle, resulting in possible diastereomers: trans- and cis-isomers.
R. P. Terekhov, A. Taldaev, E. V. Bocharov, D. I. Pankov, A. D. Savina, I. A. Selivanova   +5 more
doaj   +1 more source

Combining pot, atom and step economy (PASE) in organic synthesis. Synthesis of tetrahydropyran-4-ones [PDF]

, 2007
The combination of pot, atom and step economy (PASE) in the synthesis of organic molecules of medium complexity can lead to a significant 'greening' of a synthetic route.
Clarke, Paul A., Martin, William H. C., Santos, Soraia   +2 more
core   +1 more source

Chemical investigation of light induced DNA bipyrimidine damage and repair [PDF]

, 2011
In all organisms, genetic information is stored in DNA and RNA. Both of these macromolecules are damaged by many exogenous and endogenous events, with UV irradiation being one of the major sources of damage.
Carell, Thomas, Heil, Korbinian, Pearson, David   +2 more
core   +1 more source