Methylx derivatives of tetrahydrobenzo‐ and benzofurocoumarins, a new class of potential photoreagents toward dna

A number of new tetracyclic furocoumarin derivatives with a linear structure or with various angular arrangements, were synthetized. The new compounds are characterized for having an additional cyclohexene or phenyl ring condensed at the 4′,5′ double bond of the furan ring of the furocoumarin nucleus. The syntheses were performed starting from the appropriate hydroxycoumarins on which the tetrahydrobenzofuran or benzofuran moiety was built. Methyl groups have been introduced into positions which look most promising for enhancement of the photoreactivity of the compounds toward DNA.