6 ACETOGENINS FROM UVARIA-TONKINESIS

From the root of Uvaria tonkinesis, six novel monotetrahydrofuran (THF ) annonaceous acetogenins, tonkinins A, B and C and tonkinesins A, B a nd C, have been isolated and purified. Their structures, characterized by the presence of either a ketone or a hydroxyl group at C-5, were e stablished on the basis of spectral evidence. The occurrence of two is omeric pairs, tonkinins A/B and tonikinesins A/B, is noteworthy. Tonki nin C and tonkinesin C are mono-THF type acetogenins with an unusual f lanking acetoxy group adjacent on one side of the THF ring. The absolu te stereochemistry of tonkinin C was revealed by the use of Mosher's m ethodology. Copyright (C) 1996 Elsevier Science Ltd