Copyright © 1996, 2001 by
Galen Daryl Knight and VitaleTherapeutics, Inc.
Base Structure of Activated Calichemicins and Esperamicins
The cores of active metabolites of calichemicins
(shown below left) and esperamicins, groups of cytotoxic anti-cancer
agents under development through the combined efforts of several pharmaceutical
companies, have carbamate and sulfur moieties in common with the much simpler
vitaletheine (below right). The prodrugs actually become more similar to
vitaletheine as they are "activated".