DERIVATIVES OF A-21978C CYCLIC PEPTIDES AND THEIR PRODUCTION

摘要

of the Invention A-21978C cyclic peptide derivatives of the formula < IMG > wherein R is a substituted benzoyl group of the formula < IMG > in which R2 is C8-C15 alkyl; X is hydrogen, chloro, bromo iodo, nitro, C1-C3 alkyl, hydroxy, C1-C3 alkoxy, or C1-C3 alkylthio; and R1 is hydrogen or an amino-protecting group; and the salts thereof, are useful new semisynthetic antibiotic agents or intermediates to such agents. These new agents can be prepared by reacting the A-21978C nucleus, prepared by deacylating the appropriately blocked A-21978C complex or any of its appropriately blocked individual factors C0, C1, C2, C3, C4 or C5, with the desired acylating agent or an activated derivative thereof.