Total and semisynthesis and in vitro studies of both enantiomers of 20-fluorocamptothecin

Abstract Both enantiomers of 20-fluorocamptothecin and the racemate have been prepared by total synthesis. The ( R )-enantiomer is essentially inactive in a topoisomerase-I/DNA assay, while the ( S )-enantiomer is much less active than (20 S )-camptothecin. The lactone ring of 20-fluorocamptothecin hydrolyzes more rapidly than that of camptothecin in PBS. The results provide insight into the role of the 20-hydroxy group in the binding of camptothecin to topoisomerase-I and DNA.