Bartanol and bartallol, novel macrodiolides from Cytospora sp. ATCC 20502
Abstract
Two new macrodiolides, bartanol 10 and bartallol 11 have been isolated from a Cytospora sp. and their structures established by a detailed study of their high field 1H and 13C NMR spectra. Unlike the other 14-membered ring macrodiolides isolated from this source, bartanol and bartallol have a novel rearranged 13-membered macrocyclic ring. The conformations of the macrocyclic ring have been deduced from the analyses of difference NOE spectra and 1H–1H coupling constants.