Synthesis and DNA Binding Properties of γ-Carbolinium Derivatives and Benzologues

Abstract

The 5 H -pyrido[4,3- b ]indole, 11 H -indolo[3,2- c ]quinoline, 5 H -benzo[ f ]pyrido[4,3- b ]indole, and 13 H -benz[5,6]indolo[3,2- c ]quinoline heteroaromatic nuclei have been synthesized by the Graebe−Ullmann method by classical heating or under microwave irradiation. These tri-, tetra-, and pentacyclic compounds were transformed into the corresponding cationic derivatives by N-alkylation, and the DNA-binding properties of the resulting cationic systems were examined using UV−vis spectroscopy, viscometric determinations, and molecular modeling techniques. The tetracyclic cations were transformed into bis-salts by means of a diethyl bispiperidine rigid chain and a more flexible polyamide linker, but the low solubility of these bis-salts made the study of their bisintercalating properties difficult.