Plant constituents biologically active to insects. VI. Antifeedants for larvae of the yellow butterfly, Eurema hecabe mandarina, in Osmunda japonica. (2).

Three antifeedants for larvae of the yellow butterfly, Eurema hecabe mandarina de l'Orza, were isolated from Osmunda japonica Thunb. and identified as osmundalin, parasorboside and methyl (3S,5S)-5-hydroxy-3-(beta-D-glucopyranosyloxy)hexanoate. In the course of isolation of the antifeedants, a new glycoside, dihydroisoosmudalin (9), was isolated together with maltol beta-D-glucopyranoside, 2-deoxy-L-ribopyranolactone, 5-hydroxymethyl.2-furfural and glycerin. The structure of 9 was elucidated as (4R,5S)-5-(beta-D-glucopyranosyloxy)hexan-4-olide on the basis of chemical and spectroscopic evidence.