A NEW SHORT WAY TO FUROCOUMARINS

The Fries rearrangement of hydroxycoumarin chloroacetates provides a n ew short way to furocoumarins. 7-Hydroxycoumarin chloroacetates have b een transformed in the presence of AlCl3 into the proper dihydrofuro[2 ,3-h]coumarin-9-ones in high yields. 8-Substituted-7-hydroxycoumarin c hloroacetates undergo into dihydrofuro[2,3-g]coumarin-6-ones in the pr esence of AlCl3. 4-Hydroxycoumarin chloroacetate has been transformed into the dihydrofuro[2,3-c]coumarin-3-one in the same conditions. Redu ction of all dihydrofurocoumarinones followed by dehydration provide t he proper furocoumarins in good yields. This new way to furocoumarins is mostly suitable for angelicin derivatives synthesis. All new coumar in derivatives have been characterised by NMR and mass spectra.