Determination of the Absolute Stereochemistry of the Epoxide of Aoe (2-Amino-8-oxo-9,10-epoxy-decanoic acid) in Cyl-1 and Cyl-2 by CD Spectra

1986 ◽  
Vol 50 (2) ◽  
pp. 517-518
Author(s):  
Akira Isogai ◽  
Seiji Takayama ◽  
Akira Hirota ◽  
Akinori Suzuki
Keyword(s):  
Decanoic Acid ◽  
Cd Spectra ◽  
The Absolute ◽  
Absolute Stereochemistry

Determination of the Absolute Stereochemistry of Cyclosmenospongine

2003 ◽  
Vol 66 (9) ◽  
pp. 1263-1265 ◽  
Author(s):  
Natalia K. Utkina ◽  
Vladimir A. Denisenko ◽  
Olga V. Scholokova ◽  
Aleksandra E. Makarchenko
Keyword(s):  
The Absolute ◽  
Absolute Stereochemistry

First synthesis and determination of the absolute stereochemistry of iso-cladospolide-B and cladospolides-B and C

2006 ◽  
Vol 47 (37) ◽  
pp. 6537-6540 ◽  
Author(s):  
G.V.M. Sharma ◽  
K. Laxmi Reddy ◽  
J. Janardhan Reddy
Keyword(s):  
The Absolute ◽  
Absolute Stereochemistry

Enzymatic Synthesis of Four Stereoisomers of 7-0xo-biopterin and Determination of the Absolute Structure of Ichthyopterin

Pteridines ◽  
1990 ◽  
Vol 2 (3) ◽  
pp. 151-156 ◽  
Author(s):  
Shin Ichiro Takikawa ◽  
Sadao Matsuura
Keyword(s):  
Enzymatic Synthesis ◽  
Side Chain ◽  
Side Chains ◽  
Enzymatic Conversion ◽  
Cd Spectra ◽  
The Absolute ◽  
Chiral Centers ◽  
Absolute Structure

Summary Enzymatic conversion of stereoisomers of biopterin (3a-d) to the 7-oxo-biopterin isomers (4a-d) was performed with a new pterin 7-oxidase extracted from carp skin. The chiral centers of the 6-side chains of biopterin isomers were preserved during the conversion, and the four possible stereoisomers of 7-oxo-biopterin (4a-d) were obtained from the corresponding biopterin isomers (3a-d). HPLC and CD spectra studies showed that natural ichthyopterin is 2-amino-6-(L-erythro-1',2' -dihydroxypropyl)-4, 7(3H,8H)-pteridinedione (4a) which has the same L-erythro structure at the side chain as natural biopterin (3a). This fact suggests that ichthyopterin is biologically derived from biopterin in these fishes.

scholarly journals Absolute Stereochemistry of the β-Hydroxy Acid Unit in Hantupeptins and Trungapeptins

2016 ◽  
Vol 11 (1) ◽  
pp. 1934578X1601100 ◽  
Author(s):  
Deepak Kumar Gupta ◽  
Gary Chi Ying Ding ◽  
Yong Chua Teo ◽  
Lik Tong Tan
Keyword(s):  
Amino Acid ◽  
Structural Feature ◽  
Absolute Configuration ◽  
Hydroxy Acid ◽  
Hplc Analysis ◽  
The Absolute ◽  
Absolute Stereochemistry ◽  
Common Structural Feature ◽  
Acid Unit

The β-hydroxy/amino acid unit is a common structural feature of many bioactive marine cyanobacterial depsipeptides. In this study, the absolute stereochemistry of the β-hydroxy acid moieties in hantupeptins and trungapeptins were determined through their synthesis and HPLC analysis of the Mosher ester derivatives. Synthesis of two3-hydroxy-2-methyloctanoic acid (Hmoa) stereoisomers, (2 S,3 R)-Hmoa and (2 S,3 S)-Hmoa, were achieved using diastereoselective asymmetric method and the retention times of all four Hmoa isomers were established indirectly by RPLC-MS analysis of their Mosher ester derivative standards. Based on the retention times of the standards, the absolute configuration of the Hmoa unit in hantupeptin C (3) and trungapeptin C (6) was assigned as (2 R,3 S)- and (2 S,3 R)-Hmoa, respectively. The use of the Mosher's reagents, coupled with HPLC analysis, provided a viable alternative to the absolute stereochemical determination of β-hydroxy acid units in depsipeptides.

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