Charminarone, a seco-pseudoguaianolide from Parthenium hysterophorus
摘要:
A novel sesquiterpenoid, charminarone, the first seco-pseudoguaianolide, has been isolated along with several known compounds from the whole plant of Parthenium hysterophorus. The structure of the new compound has been settled as 1,10-seco-dihydro-isoparthenin 1, 10-dione from its spectral data as well as from its conversion by reductive coupling reaction with Zn/TiCl4 reagent to the known compound, anhydrodihydroisoparthenin. The reagent Zn/TiCl4 has been used here for the first time to construct the seven membered ring of a pseudoguaianolide sesquiterpenoid. (C) 2003 Elsevier Science Ltd. All rights reserved.
Enantioselective synthesis of neoambrosin, parthenin, and dihydroisoparthenin
摘要:
Enantioselective synthesis of the titled ambrosanolides is described. Use of the trimethylsilyl group as an anchor contributed to the stereoselective introduction of two methyl groups.