Isomers and Tautomers of Hymenialdisine and Debromohymenialdisine

Abstract
- The 10E-stereoisomers of hymenialdisine and debromohymenialdisine were isolated from the marine sponge Stylotella aurantium from Palau. The structures of (10E)-debromohymenialdisine (3) and (10E)-hymenialdisine (4) were elucidated by interpretation of spectral data. The two sets of signals in the NMR spectra of DMSO solutions of hymenialdisine and debromohymenialdisine are due to tautomerism.