Syntheses of Several Compounds Related to Helminthosporol and their Plant-growth Regulating Activities

Abstract

Several compounds related to helminthosporol (I), a natural plant-growth promoter, were prepared from I and their plant-growth regulating activities were examined together with those of the derivatives reported in the previous paper, ¹⁾ using rice and lettuce seedlings. Among the compounds tested, helminthosporic acid (III) exhibited marked elongation effect to the shoot growth of rice and lettuce seedlings, whereas the effect of I was specific to the former. Results of the biological test are reported in details.