14858-07-2Relevant articles and documents
Discoveries and Challenges en Route to Swinhoeisterol A
Duecker, Fenja L.,Heinze, Robert C.,Steinhauer, Simon,Heretsch, Philipp
, p. 9971 - 9981 (2020)
In this work, a full account of the authors’ synthetic studies is reported that culminated in the first synthesis of 13(14→8),14(8→7)diabeo-steroid swinhoeisterol A as well as the related dankasterones A and B, 13(14→8)abeo-steroids, and periconiastone A, a 13(14→8)abeo-4,14-cyclo-steroid. Experiments are described in detail that provided further insight into the mechanism of the switchable radical framework reconstruction approach. By discussing failed strategies and tactics towards swinhoeisterol A, the successful route that also allowed an access to structurally closely related analogues, such as Δ22-24-epi-swinhoeisterol A, is eventually presented.
Sterol constituents from the fruit bodies of Grifola frondosa (Fr.) S. F. Gray
Ishizuka, Takaaki,Yaoita, Yasunori,Kikuchi, Masao
, p. 1756 - 1760 (1997)
Four new sterols, 5α,6α-epoxy,(22E,24R)-ergosta-8(14),22-diene- 3β,7β-diol (1), (22E,24R)-ergosta-8,22-diene-3β,5α,6β,7α-tetrol (2), (22E,24R)-ergosta-7,9(11),22-triene-3β,5α,6β-triol (3) and 3β,5α,6β- trihydroxy-(22E,24R)ergost-22-en-7-one (4), have been isolated from the fruit bodies of Grifola frondosa (FR.) S. F. GRAY (Polyporaceae) together with fourteen known ones (518), of which two (5 and 6) are reported for the first time from a natural source. The structures of these compounds were elucidated on the basis of spectral data.
Synthesis of the Alleged Structures of Fortisterol and Herbarulide and Structural Revision of Herbarulide
Duecker, Fenja L.,Heinze, Robert C.,Heretsch, Philipp,Mueller, Mira,Zhang, Sudong
supporting information, (2020/02/13)
The alleged structures of 5,6-epoxy-5,6-secosteroids fortisterol and herbarulide differ only in the stereoconfiguration of C24. Applying insights into the hypothetical biosynthesis of this class of natural products, we devised a short synthetic access (four and eight steps, respectively) starting from commercial ergosterol and featuring an alkoxy radical rearrangement. The comparison of nuclear magnetic resonance spectroscopic data revealed herbarulide having the proposed structure of fortisterol, whereas synthesis of another two diastereomers could not conclusively prove the true structure of fortisterol. Along the way, a high-yielding and scalable access to the infamous Burawoy's ketone not requiring chromium(VI) reagents was developed.
Structure-Activity Relationship of Brassinosteroids with Respect to the A/B-Ring Functional Groups
Takatsuto, Suguru,Ikekawa, Nobuo,Morishita, Tadashi,Abe, Hiroshi
, p. 211 - 216 (2007/10/02)
In order to examine the biological role of the A/B-ring functional groups of plant-growth-promoting brassinosteroids, twenty-three brassinosteroids, with some modifications at rings A and B (1-15 and 22-29) were bioassayed by means of the rice-lamina inclination test.The results showed that 1) removal of one or two hydroxyl groups from the A-ring reduced the biological activity of the steroids; 2) the 7-oxalactone brassinosteroids were almost as active as the corresponding 6-oxo steroids and they were much more active than their regioisomeric 6-oxalactone counterparts; 3) introduction of a double bond at the C-7 position and a hydroxyl group at the C-5 position of 6-oxo brassinosteroids significantly decreased the biological activity of the hormonal steroids.These data suggest that the presence of a 2α,3α-diol, 7-oxalactone or 6-oxo group, and the A/B-trans ring junction are important for high biological activity. Keywords ---- plant growth promoter; brassinosteroid; structure-activity relationship; ricelamina inclination test
