Absolute stereochemistry of the β-hydroxy acid unit in hantupeptins and trungapeptins

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Gupta, D. K., Chi, G. Y. D., Teo, Y. C., & Tan, L. T. (2015). Absolute stereochemistry of the β-hydroxy acid unit in hantupeptins and trungapeptins. Natural Product Communications, 11, 1-4.
Author
Gupta, Deepak Kumar
•
Ding, Gary Chi Ying
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Teo, Yong Chua 
•
Tan, Lik Tong 
Abstract
Theβ-hydroxyl amino acid unit is a common structural feature of many bioactive marine cyanobacterial depsipeptides. In this study, the absolute stereochemistry of the β-hydroxyl 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, (2S,3R)-Hmoa and (2S,3S)-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 (2R,3S)- and (2S,3R)-Hmoa, respectively. The use of the Mosher's reagents, coupled with HPLC analysis, provided a viable alternative to the absolute stereochemical determination of -hydroxy acid units in depsipeptides.
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Date Issued
2015
Publisher
Sage
Journal
Natural Product Communications