Stereochemistry of diastereomeric neolignans fromPiper hookeri by nuclear magnetic resonance spectroscopy

Abstract

A new 8.1′ type neolignan, (8R,1′S or 8S,1′R)‐4‐[2‐(1,3‐benzodioxolo‐5‐yl)‐1‐methylethyl]‐2,5‐dimethoxy‐1‐propenyl‐2,5‐cyclohexadienone, hookerinone B a diastereomer of hookerinone A, and a pair of 8.3′ type diastereomeric neolignans, lancifolin C and lancifolin D, were isolated from the alchoholic extracts of the medicinal plant Piper hookeri. The absolute configurations of these neolignans and of a third diastereomeric pair, dihydroisofutoquinol A and dihydroisofutoquinol B, were established by nuclear magnetic resonance spectroscopic methods. © 1998 John Wiley & Sons, Ltd.