摘要 |
The invention provides compounds of formula I: wherein Y is F or Br; or a pharmaceutically acceptable salt thereof. The compounds are effective antitumor agents. The invention also provides pharmaceutical compositions comprising a compound of formula I or a salt thereof, intermediates useful for preparing a compound of formula I, therapeutic methods comprising administering a compound of formula I or a salt thereof to a mammal in need thereof, and methods of inhibiting cancer cells. |