Synthesis, Crystal Structure, and Properties of 2H-4,8-Dimethylfuro[2′,3′:5,6] naphtho [1,2-b] pyran-2-one, a Novel DNA Intercalator

The furonaphthopyrone 6, a novel DNA intercalator, was synthesized in two steps (ca. 56% overall yield) starting from naphthopyrone 3. The new naphthopyrone derivatives 4 and 6 were fully characterized and the absorption and fluorescence spectroscopic properties of 6 were determined. The dark interactions of furonaphthopyrone 1 and 6 with DNA have been investigated by a fluorescence quenching technique and their apparent Scatchard binding constants were calculated. The crystal structure of 6 was determined. The planarity of 6 and the geometry of the active double bond between the α-pyrone and the furan moieties of 6 suggest that furonaphthopyrones are efficient monofunctional DNA intercalators.