Biogenetic Studies on Oxazolomycin, a Metabolite of Streptomyces albus (Strain JA 3453)

Feeding experiments with sodium [13C]‐labelled acetate, sodium [1‐13C]propionate, L‐[methyl‐13C]methionine, L‐[1‐13C]‐alanine, and [1‐13C]glycine on Streptomyces albus (strain JA 3453) produced oxazolomycin (1), whose NMR analysis provided information about the biogenetic construction of its carbon skeleton. Both the (E,E)‐diene and the (Z,Z,E)‐triene chains are built up from acetate via the polyketide pathway each starting with a glycine‐derived building block. The use of glycine predicts an uncommon biosynthetic pathway leading to oxazole rings in actinomycetes. The spiro‐ring system in 1 is formed from acetate, glycine, and a C3 unit of unknown origin. The oxazolomycin producing organism combines carbon, oxygen, and nitrogen methylation activity via methionine (C1 pool) for the biosynthesis of 1.