Itiro Yosioka

Soil bacterial hydrolysis leading to genuine aglycone—VIII : Structures of a genuine sapogenol protobassic acid and a prosapogenol of seed kernels of Madhuca longifolia L.

Abstract By virtue of the soil bacterial hydrolysis method, a genuine sapogenol named protobassic acid was obtained from the saponins of seed kernels of Madhuca longifolia L. (Sapotaceae), and the structure has been established as 2β, 3β, 6β, 23-tetrahydroxy-olean-12-en-28-oic acid (2a). In addition, the structure of a prosapogenol designated as Mi-glycoside I, which was isolated concurrently during the above microbiological procedure, has been elucidated as 3-0-β- d -glucopyranosyl-protobassic acid (3a). It has been suggested that protobassic acid (2a) may be a common sapogenol of several sapotaceous plants in place of hitherto approved bassic acid (1a).

Photochemical transformation leading to eupteleogenin—II: Attempt to introduce terminal methylene moiety and transformation of spergulagenic acid to eupteleogenin

Abstract As a continuation of the preceding paper, to search for the photochemical means to induce a terminal methylene moiety, which is another unique function of eupteleogenin (1a), photolysis of leucotylic acid derivatives (2a-d) has been pursued as the model experiment. Although the aimed terminal methylene compound (3a) was obtained, the method has been found inapplicable for decarboxylation of 7a, b. Based on the combined evidence of this and the preceding papers, the transformation of spergulagenic acid derivatives (5a, b) into eupteleogenin acetate (1b) has been accomplished, in which decarboxylation of 7b was realized by lead tetraacetate oxidation.