| abstract |
A-21978C cyclic peptides of the formula <IMAGE> <IMAGE> wherein R is selected from the group consisting of hydrogen, an amino-protecting group , 8-methyldecanoyl, 10-methylundecanoyl, 10-methyldodecanoyl, the specific C10-alkanoyl group of A-21978C factor C0 and the specific C12-alkanoyl groups of A-21978C factors C4 and C5; R1 and R2 are, independently, hydrogen or an amino-protecting group, and salts thereof, are prepared by enzymatic deacylation of an antibiotic selected from A-21978C complex, A-21978C factors C0, C1, C2, C3, C4 and C5 and blocked A-21978C complex and factors C0, C1, C2, C3, C4 and C5, using an enzyme produced by the Actinoplanaceae, preferably by Actinoplanes utahensis. The A-21978C cyclic peptides and salts thereof are useful intermediates to prepare new semi-synthetic antibacterial agents. |