The structure of the flavonoids from Rhodiola algida. II

Summary New flavonoid glycosides have been obtained from the roots ofRhodiola algida: rhodalgin (I), composition C₂₀H₁₈O₁₁, mp 239–240°C; acetylrhodalgin (II) C₂₂H₂₀O₁₂, mp 223–224°C; diacetylrhodalgin (III), C₂₄H₂₂O₁₃, mp 208–209°C; and triacetylrhodalgin (IV), C₂₆H₂₄O₁₄, mp 230–231°C.It has been established that they have the following structures: (I), 3,4,5,7,8-pentahydroxyflavone 8-O--L-arabinopyranoside; (II), 3,4,5,7,8-pentahydroxyflavone 8-O-(3-O-acetyl--L-arabinopyranoside; (III), 3,4,5,7,8-pentahydroxyflavone 8-O-(2,3-di-O-acetyl)--D-xylopyranoside; and (IV), 3,4,5,7,8-pentahydroxyflavone 8-O-(2,34-tri-O-acetyl)--D-xylopyranoside. The -L-arabinopyranose and -D-xylopyranose are present in these compounds in the C1 conformations.In the performance of this investigation, the authors consulted O. S. Chizhov, and M. B. Zoltarev (N. D. Zelinskii Institute of Organic Chemistry of the Academy of Sciences of the USSR) and V. I. Sheichenko (All-Union Institute of Medicinal plants).All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 712–720. November–December, 1975.