Synthesis and evaluation of the antioxidant and antiinflammatory activities of some benzo[l]khellactone derivatives and analogues.

Treatment of 3-hydroxy-beta-lapachone 4 with ylide 5 gave the coumarin derivative 7a, which was transformed to compounds 10-14. Compound 14 was then transformed to benzo[f]seselin 15 as well as to benzo[l]khellactones 16, 18 from which the title compounds 17, 19(I), 19(II), 20, 21(I) and 21(II) were prepared. All the tested compounds were found to interact with DPPH in a concentration and time dependent manner. All the tested compounds highly inhibited the soybean lipoxygenase, whereas compounds 12, 17 and 19(II) highly compete with DMSO for (*)OH. Compounds 7a, 7b, 12 and 17 induced at 48.7-58.9% protection against carrageenin induced rat paw edema.