title: New bisfuran derivative from sarsasapogenin. An X-ray and NMR analysis.
abstract: The new bisfuran derivative, (22S,23S)-22,23-dihydroxy-23,26-epoxyfurostane, was obtained from the known oxidation of sarsasapogenin acetate with NaNO2/BF3 in 5% aqueous acetic acid. The structure of was established using one and two-dimensional 1H, 13C experiments (DEPT, COSY, HETCOR and HMBC) and the configurations at the newly formed stereogenic centers were established as 22S,23S by an X-ray diffraction analysis. Addition of TiCl4 to bisfuran 5 confirmed that this compound is an intermediate in the rearrangement to 22-oxo-23-spiroketals since it was transformed quantitatively into the latter product. The 23-nitroimino intermediate 2 was isolated from the same reaction and its structure established also by an X-ray diffraction analysis; this compound was further transformed into the 23-nitramine 7 which could find application in functionalization of position 24.
authors.affiliation: Departamento de Química, CINVESTAV-IPN, Apdo. Postal 14-740, 07000 México, D.F., Mexico.
authors.forename: Yliana
authors.initials: Y
authors.lastname: López
authors.forename: Rosa
authors.initials: R
authors.lastname: Santillan
authors.forename: Norberto
authors.initials: N
authors.lastname: Farfán
mesh_terms: D002776:Cholestanes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry*; D008279:Magnetic Resonance Imaging; D008958:Models, Molecular; D012502:Sapogenins / Q000737:chemistry*; D013150:Spirostans / Q000737:chemistry*; D014315:Triterpenes / Q000138:chemical synthesis
chemical_list: C509626:22,23-dihydroxy-23,26-epoxyfurostane; D002776:Cholestanes; D005663:Furans; D012502:Sapogenins; D013150:Spirostans; D014315:Triterpenes; C039281:furan