Title: Absolute configuration of oryzalexin A and structures of its related phytoalexins isolated from rice blast leaves infected with Pyricularia oryzae.
Abstract: Oryzalexin A has been isolated from rice (O.sativa) blast leaves infected with P. oryzae along with a group of novel phytoalexins, and its primary structure with a relative configuration was elucidated as 3-oxy-7-oxosandaracopimaradiene (I).1}In this report we wish to present the absolute configuration of this oryzalexin A (I) as well as the structures and absolute configurations of oryzalexins B(II) and C (III), which were newly isolated from the above phytoalexin group and consist a group of novel (H-)-sandaracopimaradiene derivatives.