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Phoriospongin A Structure Elucidation

Phoriospongin A

The Initial Challenge

In 2002, Robert Capon and co-workers1 identified two new nematocidal depsipeptides, identified as phoriospongins A and B through bioassay-directed fractionation of two southern Australian sponges, Phoriospongia sp. and Callyspongia bilamellata. The structures of the phoriospongins were determined by detailed spectroscopic analysis and comparison with the previously reported sponge depsipeptide cyclolithistide A. The initial experimental data was then submitted to the Structure Elucidator Challenge to determine if the software could propose the same structure.

The Evidence

The CASE (Computer Assisted Structure Elucidation) Investigation

The Molecular Connectivity Diagram produced by Structure Elucidator


For this example, ACD/Structure Elucidator detected and improved all but one of the non-standard COSY and HMBC correlations, and was able to successfully determine the correct structure for a large cyclic peptide comprising of ~80 skeletal atoms.

ACD/Structure Elucidator is a complete elucidation package offering tools to speed up the elucidation process and ensure that no candidate is overlooked. Learn more

dF—the average deviation between the experimentally observed carbon chemical shifts and the carbon chemical shifts predicted using fast (increment based) prediction methods
dH—the average deviation between the experimentally observed proton chemical shifts and the predicted proton chemical shifts using accurate (HOSE code based) prediction methods
dΣ = dA + 20-dH—generalized match factor that takes into account deviations calculated by the accurate prediction methods both for 13C and 1H NMR spectra

1Robert J. Capon, Joanne Ford, Ernest Lacey, Jennifer H. Gill, Kirstin Heiland, and Thomas Friedel J. Nat. Prod., 65:358–363, 2002.

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