Results 51 to 60 of about 20,067 (277)

Iridium‐Catalyzed Ionic Hydrogenation of Multi‐Aza Heterocycles

Angewandte Chemie, EarlyView.
Saturated nitrogen‐containing heterocycles are ubiquitous in bioactive molecules and are thus attractive synthetic targets. A readily accessible cyclometalated iridium(III) complex reduces 14 different aromatic aza heterocycles to (partially)saturated multi aza‐heterocycles enlarging accessible chemical space while displaying high tolerance toward ...
Arthur Despois, Nicolai Cramer
wiley   +2 more sources

Pyrethroid Stereoisomerism: Diastereomeric and Enantiomeric Selectivity in Environmental Matrices – A Review

Orbital: The Electronic Journal of Chemistry, 2018
Pyrethroids are chiral insecticides characterized by stereoisomerism, which occurs due to the presence of one to three asymmetric (chiral) carbons, generating one or two pairs of cis/trans diastereomers, and two or four pairs of enantiomers ...
Cláudio Ernesto Taveira Parente, Claudio Eduardo Azevedo-Silva, Rodrigo Ornellas Meire, Olaf Malm   +3 more
doaj   +3 more sources

Reversed-phase HPLC separation of the diastereomers of compound 1. [PDF]

, 2014
Panel A: chromatogram of the racemic mix of the diastereomers of compound 1 analyzed by reversed-phase HPLC using a XBridge C18 column, 3.5 µm, 4.6×150 mm (Waters Inc., Waltham, Mass.
Alan D. Michelson (344645), Milka Yanachkova (550364), Hung Chang (550361), George E. Wright (550366), Ivan B. Yanachkov (550362), YouFu Li (550365), Marc R. Barnard (344651), Edward J. Dix (550363), Andrew L. Frelinger III (344646)   +8 more
core   +1 more source

Diastereomers of 5-S-cysteinyldopa

Acta Dermato-Venereologica, 1983
Diastereomers of 5-S-cysteinyldopa formed from D-dopa and L-cysteine or from L-dopa and D-cysteine can be separated from 5-S-cysteinyldopa formed from L-dopa and L-cysteine by liquid chromatography. The diastereomers have a great potential as internal standards in the analysis of 5-S-cysteinyldopa.
G, Agrup, L E, Edholm, H, Rorsman, E, Rosengren   +3 more
openaire   +2 more sources

Synthesis of Six Natural Products Enabled by Selective Hydroxylation of Orcinaldehyde‐Like Substrates With an Enzyme Library

Angewandte Chemie, EarlyView.
Achieving selective (sp3)C–H hydroxylation can streamline the synthesis of complex organic molecules. Biocatalysis presents an opportunity to realize this transformation, however, identifying useful enzymes that enable synthetic strategies can be a challenge due to limitations in enzyme substrate scope.
Gonzalo J. Villegas Rodríguez, Evan O. Romero, Jonathan C. Perkins, Diego N. Rojas, Maximilian S. Hrigora, Alison R. H. Narayan   +5 more
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

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

Biodegradability and toxicity of monorhamnolipid biosurfactant diastereomers [PDF]

Journal of Hazardous Materials, 2019
Synthetic monorhamnolipids differ from biologically produced material because they are produced as single congeners, depending on the β-hydroxyalkanoic acid used during synthesis. Each congener is produced as one of four possible diastereomers resulting from two chiral centers at the carbinols of the lipid tails [(R,R), (R,S), (S,R) and (S,S)].
David E. Hogan, Fei Tian, Scott W. Malm, Christopher Olivares, Ricardo Palos Pacheco, Michael T. Simonich, Anoop S. Hunjan, Robert L. Tanguay, Walter T. Klimecki, Robin Polt, Jeanne E. Pemberton, Joan E. Curry, Raina M. Maier   +12 more
openaire   +2 more sources

Synthesis of four diastereomers and structural revision of tetradenolide [PDF]

, 2014
Four diastereomers of tetradenolide, a cytotoxic α-pyrone isolated from Tetradenia riparia, were synthesized stereoselectively using the Z-selective Horner–Emmons reaction followed by acid catalyzed lactonization.
Makabe, Hidefumi, Tokuda, Maki, Nohara, Yukie, Tokuda, Maki, Kurogome, Yuji, Katoh, Rieko, Makabe, Hidefumi, Kurogome, Yuji, Nohara, Yukie, Hattori, Yasunao, Hattori, Yasunao, Katoh, Rieko   +11 more
core   +2 more sources

Harnessing the Reactivity of Sulfinate Salts With Cystine: An Umpolung Approach to Residue‐Specific Peptide Modification

Angewandte Chemie, EarlyView.
While cysteine is widely employed as a nucleophilic handle for peptide modification, the electrophilicity of the oxidized form, cystine, is rarely exploited. This study describes a mild, photochemical coupling of sulfinate salts with peptide disulfides.
Joshua M. Hammond, Esteban Suárez‐Picado, Lena von Sydow, Hanna Bruss, Laurent Knerr, Magnus Johansson, Anaïs Noisier, Lara R. Malins   +7 more
wiley   +2 more sources