title: Revision of the absolute configurations of bethosides B and C and their aglycone.
abstract: The absolute stereochemistry of the steroidal saponins bethosides B and C was previously assigned as (22R,25R) on the basis of work that employed Horeau's method. Our studies of helosides A and B created doubt about both the original assignment and consequently our conclusion that relied upon it. The absolute configurations of bethosides B and C are revised to (22S,25R) following X-ray crystallographic analysis of their aglycone. Synthesis and full spectral characterization of both the 22R and 22S aglycones is reported to facilitate future stereochemical assignments in this series of saponins.
authors.affiliation: School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia.
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Challinor
authors.forename: Patricia Y
authors.initials: PY
authors.lastname: Hayes
authors.forename: Paul V
authors.initials: PV
authors.lastname: Bernhardt
authors.forename: William
authors.initials: W
authors.lastname: Kitching
authors.forename: Reginald P
authors.initials: RP
authors.lastname: Lehmann
authors.forename: James J
authors.initials: JJ
authors.lastname: De Voss
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006027:Glycosides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D010840:Phytosterols / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D006027:Glycosides; D010840:Phytosterols; D012503:Saponins; C569682:bethoside B; C569681:bethoside C