Antibiotics from Gliding Bacteria, LIV. Isolation and Structure Elucidation of Soraphen A_1α, a Novel Antifungal Macrolide from <i>Sorangium cellulosum</i>

Abstract

Abstract From the myxobacterium Sorangium cellulosum , strain So ce26, a novel group of highly active antifungal metabolites was isolated. Large‐scale production of the basic compound soraphen A 1α ( 1 ) was achieved by fermentation in the presence of the adsorber resin XAD‐16, extraction and crystallization. The 18‐membered macrolide structure of 1 was determined by spectroscopic methods. X‐ray crystal structure analysis revealed the absolute configuration of the ten asymmetric centers. According to proton coupling constants and difference NOE measurements the solution conformation in CDCl 3 and [D 6 ]DMSO is very similar to that in the crystal structure.