Misassigned Polyoxygenated Sterols and Reassignments of Their Structures

This review will summarize the authors’ studies on the reassignments of structures of 9 natural polyoxygenated sterols (24S)-24-ethylcholest-8-ene-3β,5α,6β,7α-tetrol (1), (24S)-24-ethylcholest-8(14)-ene-3β,5α,6β,7α-tetrol (2), (22E)-24-methylcholesta-8(14),22-diene-3β,5α,6β,7α-tetrol (3), 5β,6β-epoxy-(22E)-ergosta-8,22-diene-3β,7β-diol (4), (22E)-ergosta-7,22-diene-3β,5α,6β,9α,14α-pentol (5), 3β,5α,6β,8β,14α-pentahydroxy-(22E)-ergost-22-en-7-one (6), 5β,6β-epoxy-24-methylenecholesta-8,24(28)-diene-3β,7α,11α-triol (7), 6β-acetoxy-(22E)-10α-ergosta-7,22-diene-3β,5α-diol (8), and 8α,9α-epoxy-(22E)-ergosta-6,22-diene-3β,5α,14α-triol (9). The structures of 1 to 9 have been reassigned as (24S)-5α,6α-epoxy-24-ethylcholest-8-ene-3β,7α-diol (16), (24S)-5α,6α-epoxy-24-ethylcholest-8(14)-ene-3β,7α-diol (17), 5α,6α-epoxy-(22E)-ergosta-8(14),22-diene-3β,7α-diol (13), 5α,6α-epoxy-(22E)-ergosta-8,22-diene-3β,7α-diol (12), (22E)-ergosta-7,22-diene-3β,5α,6β,9α,14β-pentol (25), 5α,6α;8α,14α-diepoxy-3β-hydroxy-(22E)-ergost-22-en-7-one (18), 5α,6α-epoxyergosta-8,24(28)-diene-3β,7α,11α-triol (21), 6β-acetoxy-(22E)-ergosta-7,22-diene-3β,5α-diol (26), and 8α,14α-epoxy-(22E)-ergosta-6,22-diene-3β,5α,9α-triol (28), respectively, from the results of careful reexamination of the published 1H and 13C NMR spectral data.