Constituents of the Zingiberaceae. X. Diastereomers of [7-Hydroxy-5-Methoxy-2-Methyl-2-(4′-Methylpent-3′-Enyl)-2H-Chromen-8-yl] [3″-Methyl-2′-(3′″-Methylbut-2″′-Enyl]-6″-Phenylcyclohex-3″-Enyl]M Ethanone (Panduratin B), a Constituent of the Red Rhizomes of a Variety of Boesenbergia pandurata

Abstract

Spectroscopic studies have established that panduratin B1 and panduratin B2, isolated from the red rhizomes of a variety of Boesenbergia pandurata ( Roxb .) Schltr ., are the diastereomers (2RS,1″ RS,2″SR,6″RS)- and (2RS,1″SR,2″RS,6″SR)-[7-hydroxy-5-methoxy-2-methyl-2-(4′-methylpent-3′-enyl)-2 H-chromen-8-yl][3″-methyl-2″-(3″′-methylbut-2″′-enyl)-6″-phenylcyclohex-3″-enyl]methanone. A synthesis of panduratin B mixture has been achieved by chromenylation of panduratin A.