New antibiotics containing the 1,2-dithiolo(4,3-b)pyrrole ring system.

In the course of our search for new antibiotics from actinomycetes it was found that the culture fluid of an unidentified Streptomyces species, isolated from a soil sample collected near Copenhagen, showed strong activity against Neisseria and certain other gram-negative organisms. The active principle was extracted from the clarified fermentation broth at pH 2 with ethyl acetate, and the concentrated extract, which according to bioautography of thin-layer chromatograms* on agar plates inoculated with Neisseria gonorrhoeae contained at least two antibiotically active compounds, was subjected to a 32 tube countercurrent distribution in the system ethyl acetate-water (pH 2) to separate the components. The main component, designated vD 844, appeared in tubes 15-20, and crystallized from ethyl acetate as neutral, optically inactive, yellow prisms, m.p. 181~182°C. Its elementary analysis and mass-spectrum (peak at m/e 214 (M+)),