Dihydrofurocoumarinones - New useful intermediates for substituted and condensed furocoumarins

Abstract

Survey of new synthetic paths to substituted and condensed furocoumarins, perspective compounds for photochemotherapy is given. These furocoumarin syntheses are based on the use of dihydrofurocoumarinones as convenient synthons. Both dihydrofuro[2,3-h]coumarin-9-ones and dihydrofuro[2,3-g]coumarin- 6-ones became available via the unusual Fries rearrangement of 7-hydroxycoumarin chloroacetates. Substitution and keto-enol reactions of dihydrofurocoumarinones followed by aromatization of dihydrofuranone moiety are key steps of substituted and condensed furo[2,3-h]- and furo[2,3-g]coumarins synthesis. We have already characterized in our previous papers many of the compounds listed in the survey. The structures of new compounds are proved by mass spectral, 1H NMR spectral and elemental analysis data.