Bis-basic derivatives of planar heterocyclic compounds

Four compounds derived from the furocoumarin, benzodipyrone and benzodifuran nucleus respectively, have been synthesized. They have molecular structures analogous to that of tilorone, namely an aromatic tricyclic moiety and two basic chains linked to the nucleus through ester or amido groups. Like tilorone, the new compounds efficiently from complexes with DNA, consisting in an intercalation of the planar aromatic moiety between two base pairs and an electrostatic interaction of the positively charged nitrogen atoms of the side chains with the phosphate groups of the macromolecule. When tested for their capacity to stimulate interferon production in mice, the compounds showed different activities; in particular the diethylamino ethyl ester of bis-benzodifuranic acid (III) proved to be twice as active as tilorone, assayed in the same experimental conditions for comparison purposes.