Marine Sterols. XI. Polyhydroxysterols of the Soft Coral Sarcophyton glaucum : Isolation and Synthesis of 5α-Cholestane-1β, 3β, 5, 6β-tetrol

Abstract

(24S)-24-Methylcholest-5-ene-3β, 25-diol (ergost-5-ene-3β, 25-diol, 3), (24S)-24-methyl-5α-cholestane-1β, 3β, 5, 6β-tetrol (5α-ergostane-1β, 3β, 5, 6β-tetrol, 2a), and a new sterol, 5α-cholestane-1β, 3β, 5, 6β-tetrol (1), were isolated from the soft coral Sarcophyton gluacum. The structure of 1 was confirmed by the spectroscopic data and by synthesis starting from ruscogenin. The configurations at C-24 of the known C₂₈-polyhydroxysterols (2-5) were shown to be (S) by proton nuclear magnetic resonance (¹H-NMR) analysis or by correlation to 22, 23-dihydrobrassicasterol (16a).