139299-95-9Relevant academic research and scientific papers
Structures of Breynins A and B, Architecturally Complex, Orally Active Hypocholesterolemic Spiroketal Glycosides
Smith, Amos B.,Keenan, Terence P.,Gallagher, Rex T.,Furst, George T.,Dormer, Peter G.
, p. 5115 - 5120 (1992)
Breynin A and its oxy congener, breynin B, were reisolated from the woody portion of the Taiwanese shrub Breynia officinalis Hemsl and formulated as 1 and 2, respectively.An arsenal of NMR techniques including DEPT, heteronuclear chemical shift correlation, 1H-1H COSY, and inverse long-range 1H-13C experiments were employed.Of particular importance for the NMR study was the preparation of breynin A undecaacetate (11).The analysis independently generated structure 1, confirming the assignment for breynin A recently reported by Ohkuma et al.However, spectral data and direct oxidation of breynin A to B demonstrated that the latter is not the hemithioacetal 8 as suggested by Ohkuma, but rather the isomeric sulfoxide 2.Improved purification of the Breynia glycosides via droplet counter-current distribution and HPLC is also described.
