| abstract |
This invention relates to compounds of the general formula (see formula I) or pharmaceutically salts thereof, wherein R1 and R2 each represent an OH group, R1 is located at the 1- or 2-position, R2 is located at the 10- or 11-position, R2 is located at the 11-position when R1 is located at the 1-position, and R2 is located at the 10-position when R1 is located at the 2-position. The compounds of the present invention have an excellent antitumor effect and are hence useful as antitumor agents in the field of medicine. |