Potential antitumor agents. 18. Bisquaternary ammonium heterocycles

Article abstract of DOI:10.1021/jm00234a013

It was earlier proposed that a close approach to overall planarity was a structural prerequisite for antileukemic activity (L1210) in bisquaternary ammonium heterocycles. The preparation of L1210 active 3,3' [bicyclo[2.2.2] octane 1,4 dicarbonylbis (imino p phenylenecarbonylimino)] bis (1 alkylpyridinium) salts, containing a nonplanar bridged ring system, negates this view. A replacement proposal is that a relatively rigid molecular framework is necessary to maintain the spacing and positioning of the quaternary functions, thereby ensuring correct site selection. Replacement of a terephthaloyl drug component by a bicyclo [2.2.2] octane 1,4 dicarbonyl residue lowers DNA binding. A terephthaloyl unit confers necessary molecular rigidity, greater DNA binding, and higher L1210 activity.