Constituents of Boesenbergia pandurata (syn. Kaempferia pandurata). III. Isolation and synthesis of (±)-boesenbergin B

Abstract

A new chalcone derivative (±)-boesenbergin B and the known (±)-panduratin A have been isolated from Boesenbergia pandurata Schl. (syn. Kaempferia pandurata Roxb.; family Zingiberaceae). Spectroscopic studies have established the structure (±)-(E)-1-[5'-hydroxy-7'-methoxy-2'-methyl- 2'-(4''-methylpent-3''-enyl)-2'H-l-benzopyran-6'-yl]-3-phenylprop-2-en-1-one for boesenbergin B. A simple synthesis of boesenbergin B has been achieved and its acid-catalysed cyclization has been studied.