Studies on the Constituents of Digitalis purpurea L. III. Gitostin, a New Cardiotonic Glycoside from Digitalis Seeds.

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Of the unknown cardioglycosides contained in the seeds of Digitalis purpurea reported in the preceding paper, substance A-VIII was isolated in crystalline state. This substance occurs as a very bitter needle crystals, m. p. 252∼254° (Kofler, uncorr.) ; [α]²1_D-3.1°, C₄₂H₆₆O₁₉·2H₂O ; negative to the Keller-Kiliani reaction, sulfuric acid layer in carmine red, and positive to Legal and Raymond reactions ; U. V. λ^EtOH_max 218mμ (log ε 4.21). Its hydrolysis with 3.5% hydrochloric acid afforded dianhydrogitoxigenin and the sugar portion was found to be digitalose and glucose by paper partition chromatography. Determination of glucose by the Borel-Hostetteler-Devel method showed the presence of two moles. This substance was found to be a new glycoside, a triglycoside, of gitoxigenin series, and was named gitostin. A structure of gitoxigenin-glucosido-glucosido-digitaloside forgitostin as the gitoxigenin-series glycoside corresponding to odoroside-G was forwarded.