Pure and Applied Chemistry

Abstract: The substitution of acridine molecule in positions 1 and/or 4 with diaminoalkylo residue may result in obtaining derivatives displaying antitumor activity. The diaminoalkylo residue can be attached to acridine either directly or indirectly as a carboxamido moiety. In the former case, the presence of appropriate substituent in position para to diaminoalkylo residue is crucial for antitumor activity. Also, heterocyclic aromatic rings condensed with the acridine core can be considered as such substituents. Additional substituents introduced into the acridine core, especially those that may be transformed into quinoid systems, significantly increase antitumor activity of modified analogs. It is, however, of utmost importance that the presence of diaminoalkylo residue is the indispensable prerequisite for biological activity of acridines. Among several groups of synthesized diaminoalkyloacridines, the most potent antineoplastic properties toward a wide spectrum of transplantable tumors are exhibited by acridine-4-carboxamides, imidazo-, triazolo-, and pyrazoloacridinones. Two derivatives belonging to the above groups, acridine-4-carboxamide DACA and imidazoacridinone C-1311, are currently in clinical trials. Other derivatives exhibiting potent antitumor activity, that could be considered as close analogs of diaminolkyloacridines, are pyrazoloacridines, one of which is currently under clinical evaluation.