Aplysiasecosterol A: A 9,11-Secosteroid with an Unprecedented Tricyclic γ-Diketone Structure from the Sea Hare Aplysia kurodai.
A new 9,11-secosteroid having an unprecedented tricyclic γ-diketone structure, aplysiasecosterol A (1), was isolated from the sea hare Aplysia kurodai. The structure was determined by one- and two-dimensional NMR spectroscopic analysis, molecular modeling studies, a comparison of experimental and calculated ECD spectra, and a modified Mosher's method. Aplysiasecosterol A (1) exhibited cytotoxicity against human myelocytic leukemia HL-60 cells. A biosynthetic pathway for 1 from a known cholesterol was proposed and includes twice α-ketol rearrangements and an intramolecular acetalization.
Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8571 (Japan).
Atsushi
A
Kawamura
Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8571 (Japan). mkita@chem.tsukuba.ac.jp.
Masaki
M
Kita
Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8571 (Japan). kigoshi@chem.tsukuba.ac.jp.
Hideo
H
Kigoshi
D000818:Animals; D001048:Aplysia / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism; D007659:Ketones / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D011789:Quantum Theory; D012632:Secosteroids / Q000737:chemistry*
D007659:Ketones; D012632:Secosteroids; C000605295:aplysiasecosterol A
biosynthesis; circular dichroism; natural products; rearrangements; structure elucidation