Ab initio calculations on (-)-calicheamicinone and some of its reactions involved in its activation and interaction with DNA.

ABSTRACT

Ab initio calculations were performed on (-)-calicheamicinone, and on the product (Z or E) of the Michael addition via a reaction with methanethiol. It is found that the sulfur moiety position versus the rest of the molecule is quite flexible. The Michael adduct featuring the carbamate group E to the sulfur moiety is more stable than the Z isomer. The Bergman reaction of the diradical formation is strongly exothermic.