Studies on Biologically Active Pteridines: III. The Absolute Configuration at the C-6 Chiral Center of Tetrahydrobiopterin Cofactor and Related Compounds1

1980 ◽  
Vol 87 (3) ◽  
pp. 951-957 ◽  
Author(s):  
Sadao MATSUURA ◽  
Takashi SUGIMOTO ◽  
Hiroyuki HASEGAWA ◽  
Shunsuke IMAIZUMI ◽  
Arata ICHIYAMA
Keyword(s):  
Absolute Configuration ◽  
Biologically Active ◽  
Chiral Center ◽  
The Absolute

scholarly journals The Assignment of the Absolute Configuration of C-22 Chiral Center in the Aglycones of Triterpene Glycosides from the Sea Cucumber Cladolabes schmeltzii and Chemical Transformations of Cladoloside C

2015 ◽  
Vol 10 (7) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Anatoly I. Kalinovsky ◽  
Alexandra S. Silchenko ◽  
Sergey A. Avilov ◽  
Vladimir I. Kalinin
Keyword(s):  
Absolute Configuration ◽  
Sea Cucumber ◽  
Triterpene Glycosides ◽  
Chiral Center ◽  
Biosynthetic Pathways ◽  
Chemical Transformations ◽  
Chemical Structures ◽  
Different Types ◽  
The Absolute ◽  
Chiral Centers

The absolute R-configuration of the C-22 chiral center in cladoloside C (1) and therefore in all related glycosides isolated from the sea cucumber Cladolabes schmeltzii has been assigned by Mosher‘s method. Some chemical transformations of the native glycoside 1 were carried out to apply this method. This resulted in the isolation and elucidation of chemical structures of progenin 2 and artefact aglycones 3 and 4, obtained from 1 and assignment of the absolute R-configuration of C-22 in the progenin 2. The coincidence of C-22 configurations in the studied compounds with those of the earlier known lanostane-type aglycone of frondoside C and holostane-type aglycone of cladoloside C (1) confirms the generic biosynthetic pathways to different types of sea cucumber glycoside aglycones. It suggests the same R-configuration of C-22 chiral centers in all the sea cucumber glycosides having C-22 functionalities.

A chiral switch: balancing between equilibrium and non-equilibrium states

2019 ◽  
Vol 55 (48) ◽  
pp. 6910-6913 ◽  
Author(s):  
Iaroslav Baglai ◽  
Michel Leeman ◽  
Bernard Kaptein ◽  
Richard M. Kellogg ◽  
Willem L. Noorduin
Keyword(s):  
Amino Acid ◽  
Absolute Configuration ◽  
Equilibrium States ◽  
Chiral Center ◽  
Equilibrium Conditions ◽  
The Absolute ◽  
Amino Acid Precursors ◽  
Non Equilibrium

Herein we introduce a “chiral switch” – a sequence of operations that alternate between equilibrium and non-equilibrium conditions to switch the absolute configuration of a chiral center. The generality and practical potential of the technique are demonstrated with three unnatural α-amino acid precursors.

scholarly journals Timeless Classics: on the Applicability of Bochvar's Three-Valued Logic B3 to the Description of an Absolute Configuration in Stereochemistry§ (Author's View)

INEOS OPEN ◽  
2021 ◽  
Vol 4 ◽  
Author(s):  
V. I. Sokolov ◽  
Keyword(s):  
Absolute Configuration ◽  
Chiral Center ◽  
The Absolute

t is shown that the absolute configuration of a chiral center can be successfully described in terms of Bochvar's three-valued logic.

Sign in / Sign up

Export Citation Format

Share Document