CP-60,993, a new dianemycin-like ionophore produced byStreptomyces hygroscopicus ATCC 39305: fermentation,isolation and characterization

Summary CP-60,993, 19-epi-dianemycin, is a novel polycyclic ether antibiotic produced byStreptomyces hygroscopicus ATCC 39305. Fermentation recovery, purification and crystallization were achieved using standard procedures. CP-60,993 was characterized as a monocarboxylic acid. Elemental analysis suggested a molecular formula of C₄₇H₇₈O₁₄ for the free acid and C₄₇H₇₇O₁₄ Na for the sodium salt. Crystalline form CP-60,993 sodium salt shows the following properties: m.p. 193205°C, E_{1 cm}^1%=157 at 232 nm, []_D^25°C+11.0 (c 1, methanol). The structure, determined by MS, PMR and CMR, differs from dianemycin only in the stereochemistry at position 19. This was confirmed by X-ray crystallography carried out on the rubidium salt of CP-60,993. It exhibited activity in vitro against Gram-positive and anaerobic bacteria, efficacy againstEimeria coccidia in vivo in poultry, and stimulation in vitro of rumen propionic acid production.