Structure Revision of Two Polyoxygenated Sterols from the Marine Sponge Neofibularia nolitangere

Abstract

Careful reexamination of the published 1 Hand 13 C-NMR spectral data of (24S)-24-ethylcholest-8-ene-3,5,6,7-tetraol (1) and (24S)-24-ethylcholest-8(14)-ene-3,5,6,7-tetraol (2), isolated from the marine sponge Neofibularia nolitangere, indicates that, in reality, compounds 1 and 2 are (24S)-5,6epoxy-24-ethylcholest-8-ene-3,7-diol (9) and (24S)-5,6-epoxy-24-ethylcholest-8(14)-ene-3,7-diol (10), respectively.

Structure Revision of (22E)-24-Methylcholesta-8(14),22-diene-3β,5α,6β,7α-tetraol from the Marine-Derived Fungus Penicillium sp

“…Sterols having a 3,5,6,7-tetrahydroxylated structure did not show a molecular ion in the EIMS and showed the dehydration ion due to the loss of one molecule of H 2 O. However, the dehydration ion of sterols having a 3,5,6,7-tetrahydroxylated structure correspond to the molecular ion for sterols having a 3,7dihydroxy-5,6-epoxy structure [2]. The interpretation of the above EIMS data was responsible for the misassignment of the structure of sterols having a 3,5,6,7-tetrahydroxylated structure [2].…”

“…The novel 3,5,6,7tetrahydroxylated structure of 1 was proposed on the basis of 1D and 2D NMR spectral data [1]. Recently we reported the structure revision of a sterol having the same A/B ring system as that of 1, (24S)-24-ethylcholest-8(14)-ene-3,5,6,7-tetraol (2), from the marine sponge Neofibularia nolitangere ( Figure 1) [2]. The structure of 2 was revised to 5,6-epoxy-(24S)-24-ethylcholest-8(14)-ene-3,7-diol (3) by reexamination of the published NMR data ( Figure 1) [2].…”

“…Recently we reported the structure revision of a sterol having the same A/B ring system as that of 1, (24S)-24-ethylcholest-8(14)-ene-3,5,6,7-tetraol (2), from the marine sponge Neofibularia nolitangere ( Figure 1) [2]. The structure of 2 was revised to 5,6-epoxy-(24S)-24-ethylcholest-8(14)-ene-3,7-diol (3) by reexamination of the published NMR data ( Figure 1) [2]. During our studies on the sterol constituents from Japanese mushrooms [3], we reported the isolation and structure elucidation of a polyoxygenated sterol having the same A/B ring system as that of 1, (22E,24R)-24-methylcholesta-8(14),22-diene-3,5,6,7-tetraol (4), from the edible mushroom Grifola frondosa ( Figure 1) [4].…”

“…However, the dehydration ion of sterols having a 3,5,6,7-tetrahydroxylated structure correspond to the molecular ion for sterols having a 3,7dihydroxy-5,6-epoxy structure [2]. The interpretation of the above EIMS data was responsible for the misassignment of the structure of sterols having a 3,5,6,7-tetrahydroxylated structure [2]. In our opinion, this is an important point to be noticed in structure elucidation of polyoxygenated sterols in order to avoid deriving a wrong structure.…”

Structure Revision of (22E)-Ergosta-7,22-diene-3β,5α,6β,9α,14α-pentol from the Spores of the Medicinal Mushroom Ganoderma Lucidum

“…Recently we reported the structure revision of two polyoxygenated sterols, (24S)-24-ethylcholest-8-ene-3,5,6,7-tetraol and (24S)-24-ethylcholest-8(14)-ene-3,5,6,7-tetraol, from the marine sponge Neofibularia nolitangere [1]. A thorough investigation of the literature data of the polyoxygenated sterols from natural sources revealed that the structure of (22E)-ergosta-7,22-diene-3,5,6,9,14-pentol (1), isolated from the spores of the medicinal mushroom Ganoderma lucidum, would need to be revised ( Figure 1) [2].…”