Abstract

Two new phytoalexins isolated from the fungus-inoculated leaflets of Erythrina sandwicensis have been identified as (—)-6aS; 11 aS-3,6 a,9-trihydroxy-10-isopentenylpterocarpan (sandwicar-pin) and (—)-6aR; 11 aR-3-hydroxy-9-methoxy-10-isopentenylpterocaipan (sandwicensin). These compounds co-occur with several known pterocarpan (demethylmedicarpin, 3,6a,9-trihydroxy-pterocarpan, phaseollidin and cristacarpin) and isoflavan (demethylvestitol and isovestitol) deriva­ tives. The preparation and spectral (UV, MS) characteristics of 3-methoxy-9-hydroxy-10-isopen-tenylpterocarpan are also described.