Abstract: | The structures of the new cycloartane methylsteroid cycloalpigenin B and its glycoside cycloalpioside B, isolated fromAstragalus alopecurus Pall. (Leguminosae) have been determined on the basis of chemical transformations with the assistance of1H and13C NMR spectroscopy and 2D NMR1H-1H and1H-13C correlations of chemical signals and IR, CD, and electron-impact mass spectrometry. Cycloalpigenin B is 20R,24S-epoxycycloartane-3,12,16,25-tetraol. A transition from cycloalpigenin B to cycloalpigenin A has been achieved. Cycloalpioside B is 20R,24S-epoxycycloartane-3,12,16,25-tetraol 3-O--D-xylopyranoside.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, FAX (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 515–521, July–August, 1994. |