Isolation of Helminthosporol as a Natural Plant Growth-regulator and its Chemical Structure

Abstract

Helminthosporol was isolated as a natural plant growth-regulator produced by Hel-minthosporium sativum and its structure was assigned as I. Oxidation of I with chromium trioxide-pyridine complex gave helminthosporal (II). The glycol (III), obtained by the reduction of I or II, yielded I by the oxidation with activated manganese dioxide. I spontaneously changed into helminthosporic acid (IV), when the former in organic solvent was let to stand in the air.