Cephabacin M1-6, new 7-methoxycephem antibiotics of bacterial origin. II. Isolation, characterization and structural determination

Six components of new cephem antibiotics, cephabacin M1-6, were isolated from the culture filtrate of Xanthomonas lactamgena YK-431 by various types of column chromatographies and preparative reverse-phase HPLC. Their structures were determined by spectroscopic analyses and degradation studies. They consist of 7-methoxydeacetylcephalosporin C as a nucleus and a tri- to heptapeptide including a new amino acid, which is bound at the 3-position with an ester bond.