| abstract |
PROBLEM TO BE SOLVED: To provide a compound useful for treating cancer and related conditions. A compound of formula (I). [Wherein, R 1 is OR 11 or the like; R 11 is H or C 1 -C 6 alkyl; R 2 is H or F; R 13 is H, phenyl, pyridyl, benzyl. R 15 and 15′ are H, C 1 -C 6 alkyl and the like; R 16 is H, C 1 -C 10 alkyl and the like. ] [Selection diagram] None |