21 ヒトデ類のステロールの研究

抄録

Two new sterols, asterosterol(VII) and amuresterol(IX) have been isolated from the sterol fraction of the asteroid, Asterias amurensis. The structure of asterosterol was identified as 22-trans-24-nor-5α-cholesta-7,22-dien-3β-ol from the spectral data and partial synthesis from ergosterol. Amuresterol, a geometrical isomer of cholesta-7,22-dien-3β-ol(VI), was characterized by spectral data and by synthesis as 22-trans-27-nor-(24R)-24-methylcholesta-7,22-dien-3β-ol(IX), a sterol with biogenetically unprecedented side chain. Occurrence of a migrated cholestane type sterol and, particularly the configuration at C-24 of amuresterol, suggests that the C_<26> sterols ubiquitous in many marine invertebrates may have been formed from demethylation of brassicasterol. Other components characterized by spectral data and combined GLC-mass spectrometry are summarized in Fig. 2.