Structure Elucidation By Nmr-Spectroscopy Of Saccharolidin-A, A Novel Antiparasitic Macrolide From Saccharothrix-Aerocolonigenes

The structure of saccharolidin A, C38H60O9, a macrolide with antiparasitic properties isolated from Saccharothrix aerocolonigenes, was determined by two-dimensional NMR using a fragment-directed approach. Complete elucidation of the structure required concerted application of a range of homo- and heteronuclear experiments (TOCSY, ROESY, HMQC, HMBC, HMQC-TOCSY). Saccharolidin A is related to the hygrolides but contains a number of unique features which distinguish it from previously reported members of this family. It is unsubstituted on C-2 and contains both a 1,3-dioxepane ring and an unsubstituted n-pentyl side-chain. The relative stereochemistry within each of the three groups of contiguous chiral centres has been determined.