5-Oxo-5 H -benzo[ e ]isochromeno-[4,3- b ]indole, a New Type of Highly Sarcomagenic Lactone

Abstract
The title compound, which belongs to a new synthetic group of polycyclic lactones derived from isocoumarin, exhibits a remarkably high degree of carcinogenicity in situ when injected in mice. Cancer-inducing activity has also been found in similar isocoumarins, a family known to include many naturally occurring substances.