A series of 2'-heterocyclic derivatives of 5-phenyl-2,5'-1H-bibenzimidazole
s were evaluated for topoisomerase I poisoning activity and cytotoxicity. T
opo I poisoning activity was associated with 2'-derivatives that possessed
a hydrogen atom capable of hydrogen bond formation, suggesting that the int
eratomic distances between such hydrogen atoms and the heteroatoms on the a
djacent benzimidazole influence activity. (C) 2000 Elsevier Science Ltd. Al
l rights reserved.