Abstract: | The holothurianEupentacta pseudoquinquisemita Deichmann collected in Kraternaya Bay, Ushishir Islands has yielded two triterpene pentaosides — the previously known cucumarioside C2, and cucumarioside H, which is a new glycoside. With the aid of13C NMR spectroscopy and solvolytic desulfation its structure has been determined as 6-acetoxy-3-(3-O-methyl--D-xylopyranosyl-(1 3)--D-glucopyranosyl-(1 4)] -D-xylopyranosyl-(1 4)] -D-xylopyranosyl-(1 2)]--D-quinovopy-ranosyl-(1 2)-(4-O-sulfato--D-xylopyranosyloxy)holosta-7,22,24(trans)-triene. Cucumarioside H was also identified inEupentacta (=Cucumaria)fraudatrix from Posyet Bay, Sea of Japan.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 221–225, March–April, 1988. |