title: Regioselective cleavage of 22-oxo-23-spiroketals. Novel cholestanic frameworks with pyranone and cyclopentenone E rings on the side chain.
abstract: The regioselective opening of the F ring of 22-oxo-23-spiroketals using a saturated solution of HCl in acetic anhydride yielded novel cholestanic frameworks with pyranone or cyclopentenone E rings. The structures of the new derivatives of sarsasapogenin, diosgenin and hecogenin thus obtained were established using one and two dimensional (1)H, (13)C experiments (DEPT, COSY, HETCOR, HMBC, ROESY, and NOESY). The X-ray analysis for compound 11b confirmed the 23R configuration for the new stereogenic center.
authors.affiliation: Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ed.B-1, C.U., Morelia, Michoacán 58030, Mexico. ylopez@umich.mx
authors.forename: Yliana
authors.initials: Y
authors.lastname: López
authors.forename: León
authors.initials: L
authors.lastname: Rodríguez
authors.forename: Rosa E
authors.initials: RE
authors.lastname: del Río
authors.forename: Norberto
authors.initials: N
authors.lastname: Farfán
authors.forename: Jacek W
authors.initials: JW
authors.lastname: Morzycki
authors.forename: Rosa
authors.initials: R
authors.lastname: Santillan
mesh_terms: D000089:Acetic Anhydrides / Q000737:chemistry; D002776:Cholestanes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003517:Cyclopentanes / Q000737:chemistry*; D004144:Diosgenin / Q000737:chemistry; D005663:Furans / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008956:Models, Chemical; D015394:Molecular Structure; D011753:Pyrones / Q000737:chemistry*; D012502:Sapogenins / Q000737:chemistry; D013141:Spiro Compounds / Q000737:chemistry*; D013150:Spirostans / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000089:Acetic Anhydrides; D002776:Cholestanes; D003517:Cyclopentanes; D005663:Furans; D011753:Pyrones; D012502:Sapogenins; D013141:Spiro Compounds; D013150:Spirostans; C520774:spiroketal; C031800:acetic anhydride; C007908:hecogenin; C046297:sarsasapogenin; D004144:Diosgenin; C013905:cyclopentenone; D006851:Hydrochloric Acid