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Updated: Jul 23, 2025

A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products
Published on: September 9, 2016
Revision of the Absolute Configurations of Chelocardin and Amidochelocardin
Asfandyar Sikandar1, Alexander Popoff1, Ravindra P Jumde1
1Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) -, Helmholtz Centre for Infection Research (HZI), Campus Building E8.1, 66123, Saarbrücken, Germany.
Abstract:
Even with the aid of the available methods, the configurational assignment of natural products can be a challenging task that is prone to errors, and it sometimes needs to be corrected after total synthesis or single-crystal X-ray diffraction (XRD) analysis. Herein, the absolute configuration of amidochelocardin is revised using a combination of XRD, NMR spectroscopy, experimental ECD spectra, and time-dependent density-functional theory (TDDFT)-ECD calculations. As amidochelocardin was obtained via biosynthetic engineering of chelocardin, we propose the same absolute configuration for chelocardin based on the similar biosynthetic origins of the two compounds and result of TDDFT-ECD calculations. The evaluation of spectral data of two closely related analogues, 6-desmethyl-chelocardin and its semisynthetic derivative 1, also supports this conclusion.
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