scholarly journals Stabilization of human telomeric RNA G-quadruplex by the water-compatible optically pure and biologically-active metallohelices

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jaroslav Malina ◽  
Peter Scott ◽  
Viktor Brabec
Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 781
Author(s):  
Agnieszka Raczyńska ◽  
Joanna Jadczyk ◽  
Małgorzata Brzezińska-Rodak

The enantioselective synthesis of organic compounds is one of the great challenges in organic synthetic chemistry due to its importance for the acquisition of biologically active derivatives, e.g., pharmaceuticals, agrochemicals, and others. This is why biological systems are increasingly applied as tools for chiral compounds synthesis or modification. The use of whole cells of “wild-type” microorganisms is one possible approach, especially as some methods allow improving the conversion degrees and controlling the stereoselectivity of the reaction without the need to introduce changes at the genetic level. Simple manipulation of the culture conditions, the form of a biocatalyst, or the appropriate composition of the biotransformation medium makes it possible to obtain optically pure products in a cheap, safe, and environmentally friendly manner. This review contains selected examples of the influence of physicochemical factors on the stereochemistry of the biocatalytic preparation of enantiomerically pure compounds, which is undertaken through kinetically controlled separation of their racemic mixtures or reduction of prochiral ketones and has an effect on the final enantiomeric purity and enantioselectivity of the reaction.


2010 ◽  
Vol 132 (27) ◽  
pp. 9328-9334 ◽  
Author(s):  
Gavin W. Collie ◽  
Gary N. Parkinson ◽  
Stephen Neidle ◽  
Frédéric Rosu ◽  
Edwin De Pauw ◽  
...  

Biochemistry ◽  
2013 ◽  
Vol 52 (13) ◽  
pp. 2176-2183 ◽  
Author(s):  
Herry Martadinata ◽  
Anh Tuân Phan
Keyword(s):  

2000 ◽  
Vol 10 (19) ◽  
pp. 2213-2216 ◽  
Author(s):  
Makoto Koizumi ◽  
Keika Akahori ◽  
Toshinori Ohmine ◽  
Shinya Tsutsumi ◽  
Junko Sone ◽  
...  

2019 ◽  
Vol 16 (4) ◽  
pp. 392-398 ◽  
Author(s):  
Nikolay V. Tkachenko ◽  
Konstantin P. Bryliakov

Optically pure 1,1′-bi-2-naphthol (BINOL) and its derivatives are among the most widely used chiral ligands and auxiliaries for asymmetric synthesis. These molecules also occur as scaffolds for various biologically active compounds. Direct oxidative coupling of 2-naphthols in the presence of chiral catalysts provides a powerful strategy for the synthesis of optically pure 1,1′-bi-2-naphthols (BINOLS). In 1978, Wynberg with co-workers discovered that a copper salt with chiral auxiliary mediates the oxidative coupling of 2-naphthols, which can be taken as the starting point for further progress in this area. Over the last decades, a number of efficient and stereoselective catalyst systems have been developed. This mini-review surveys the aerobic asymmetric oxidative coupling of 2-naphthols catalyzed by transition metal complexes reported since 1995.


2020 ◽  
Vol 17 ◽  
Author(s):  
Merve Karaoglu ◽  
Feray Aydogan ◽  
Cigdem Yolacan

: The aldol reaction which is the most important one among the C-C bond forming reactions, is widely used by synthetic organic chemists to obtain β-hydroxycarbonyl compounds which are important starting components for biologically active compounds in optically pure form. In this research, five Pro-Phe derivatives were synthesized by simple amidation reactions and characterized by their spectral data. Their catalytic activities in asymmetric aldol reaction were investigated. The catalytic activity studies were performed with aliphatic ketones and various aromatic aldehydes. Especially, (S)-methyl 3-mercapto-2-((S)-3-phenyl-2-((S)-pyrrolidine-2-carboxamido)propanamido)propanoate showed good catalytic activities in water at 0 oC in the presence of p-nitrobenzoic acid cocatalyst. The enantioselectivities were upto 90.4%, the diastereomeric ratios were upto 97/3 and yields were 99%. The results showed that these organocatalysts were promising organocatalysts for aldol reaction. Besides, this catalyst showed its best catalytic activities in water which is also important contribution to green chemistry requirements.


1997 ◽  
Vol 52 (3) ◽  
pp. 413-418 ◽  
Author(s):  
Muhammad Shaiq Ali ◽  
Tomoya Kitazume ◽  
Viqar Uddin Ahmad

Abstract A fluorinated substrate 6 was prepared and then the enantiomers (6a and 7a) were separated by an enzyme in presence of an acetylating agent. The optical purity of 6a and 7a were determined by derivatising them into their MTPA -esters and then by taking their 19F NMR spectra. It was observed that, PL 266 (enzyme), benzene (solvent), 24 h (time), 40 °C (temp.) and vinyl acetate (acetylating agent) were the ideal conditions for racemic resolution. The optical purity was further improved by changing the solvent (hexane), amount of enzyme (PL 266; 3000 units), reaction time (12 h) and amount of acetylating agent (vinyl acetate; two molar). The optically pure species was used for the preparation of E and Z alkenes.


2010 ◽  
Vol 132 (21) ◽  
pp. 7231-7233 ◽  
Author(s):  
Yan Xu ◽  
Takumi Ishizuka ◽  
Takashi Kimura ◽  
Makoto Komiyama

2018 ◽  
Vol 9 (10) ◽  
pp. 2498-2503
Author(s):  
Irene Gutiérrez ◽  
Miguel Garavís ◽  
Sara de Lorenzo ◽  
Alfredo Villasante ◽  
Carlos González ◽  
...  
Keyword(s):  

2008 ◽  
Vol 52 (1) ◽  
pp. 175-176 ◽  
Author(s):  
Y. Xu ◽  
K. Kaminaga ◽  
M. Komiyama

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