Stereochemistry of diastereomeric neolignans fromPiper hookeri by nuclear magnetic resonance spectroscopy

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.