4-Hydroxymethyl- and 4-methoxymethylfuro[2,3-h]quinolin-2(1H)-ones: synthesis and biological properties.

4-Hydroxymethyl-1,6,8-trimethylfuro[2,3-h]quinolin-2(1H)-one (HOFQ) was prepared by a new profitable way, which allowed to synthesize also 4-methoxymethyl-1,6,8-trimethylfuro[2,3-h]quinolin-2(1H)-one (MOFQ), and 4-hydroxymethyl-6,8-dimethylfuro[2,3-h]quinolin-2(1H)-one (HOHFQ). Some biological activities of the three compounds were studied in comparison with 8-MOP. In the dark, they inhibited topoisomerase II, leading to a moderate antiproliferative activity in mammalian cells. The antiproliferative activity was also tested upon UVA irradiation in mammalian cells: all compounds showed higher activity than 8-MOP, without mutagenicity and skin phototoxicity, with the best results for HOFQ. Photobinding to DNA was investigated, demonstrating a different sequence specificity for these furoquinolinones in comparison with furocoumarins. For all these features, HOFQ and the other analogues appeared very promising photochemotherapeutic agents, whose mechanism of action will be further investigated.