Synthetic studies on natural products, part V - Chemical and biochemical modifications of parthenin

Parthenin, a medicinally important natural sesquiterpenoid and a potent all elochemical underwent different regio- and stereoselective modifications to several interesting analogues by chemical and biochemical means. The compo und was treated with various common reducing agents including NaBH4, NaBH4/ I-2, Na/EtOH, Mg/MeOH and Zn/HOAc as well as with different oxidizing agent s including m-CPBA and dilute HCl under different reaction conditions. The retention of the alpha-methylene-gamma-lactone moiety which plays a vital r ole for bioactivity of the compound was observed in some of the reaction pr oducts. The microwave irradiation of the compound afforded anhydroparthenin as the only product. Baker's yeast reduction of parthenin was investigated for the first time and yielded the naturally occurring dihydrocoronopilin. (C) 1999 Elsevier Science Ltd. All rights reserved.