Studies on the Constituents of Digitalis purpurea L. XXIV. On the Structures of Purlanosides-A and -B.

Abstract

It was already reported that purlanosides-A and -B were isomers of lanatosides-A and -B. By partial acid hydrolysis, purlanoside-A afforded three new products and one of them was found to be digitoxigenin acetyldigitoxoside, by subsequent deacetylation and acid hydrolysis. Therefore, it was assumed that the acetyl group of purlanoside-A is in the first digitoxose and its structure is formulated as digitoxigenin glucosido-bisdigitoxo-sido-acetyldigitoxoside. Purlanoside-B also afforded gitoxigenin acetyldigitoxoside by the same hydrolysis. Therefore, the acetyl group is also in the first digitoxose, and its structure is formulated as gitoxigenin glucosido-bisdigitoxosido-acetyldigitoxoside. Further, it was determined that the acetyl groups of acetyldigitoxin-γ and acetyl-gitoxin-γ are in the first digitoxose.