Structure Elucidation at the Nanomole Scale. 2. Hemi-phorboxazole A from Phorbas sp.

Hemi-phorboxazole A, a minor truncated analogue of phorboxazole A from the marine sponge Phorbas sp., was isolated in a total yield of 16.5 mu g (28 nmol). The structure was elucidated by application of integrated nanomole-scale natural product techniques, including cryomicroprobe NMR, H-1-coupled HSQC, and circular dichroism (CD).