| 摘要 |
A compound of formula I Formula I wherein R1 is of formula II Formula II wherein R4 and R5 , which may be the same or different, are bromo, chloro, iodo or alkylsulphonyl: R2 is of formula III Formula III wherein R6 and R7 , which may be the same or different, are H, alkyl, aryl, carboxy, hydroxy or amino and n is 0-10; and R is hydroxy or a group capable of being cleared and replaced by a radical having an antigen binding site or is a radical having an antigen binding site. Compounds of the present invention are useful as antitumor agents. |
