IB-96212, a Novel Cytotoxic Macrolide Produced by a Marine Micromonospora

II. Physico-chemical Properties and Structure Determination

Abstract

IB-96212, is a new member of spiroketal containing macrolide class of fermentationderived natural products isolated from mycelial extracts of Micromonospora sp. The structure consists of a new aglycone which possesses a 26-membered macrolide ring system and of one deoxy sugar identified as L-rhodinose, this structure represents the first reported spiroketal macrolide natural product related to other macrolides, such as oligomycins, dunaimycins, citovaricin, rutamycin and ossamycin.