Stoffwechselprodukte von Mikroorganismen. 236. Mitteilung . Schwefelhaltige Ansa‐Verbindungen des Naphthomycin‐Typus

Metabolites of Microorganisms. Sulfur‐Containing Ansa Compounds of the Naphthomycin Type From a strain of Streptomyces (Tü 2357) in addition to naphthomycin A, 4 new yellow pigments were isolated and their structures determined by spectroscopic comparison with naphthomycin A. Whereas the naphthomycins D and E are simple derivatives of naphthomycin A, having OH and H, respectively, instead of Cl, the naphthomycins F and G contain an N ‐acetylcysteine residue linked to the aromatic moiety by a thioether group. Degradations with O 3 yielded identical products from the naphthomycins A, D, F, and G, showing coincident configurations in parts of the molecules. Naphthomycin F shows some biological activity against gram‐positive bacteria and fungi, although much weaker than naphthomycin A. The naphthomycins D, E, and G are inactive against microorganisms.