Crystal structures of three bicyclic carbohydrate derivatives

  • The title compounds, [(1R,3R,4R,5R,6S)-4,5-bis­(acet­yloxy)-7-oxo-2-oxabi­cyclo[4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acet­yloxy-7-hy­droxy­imino-2-oxobi­cyclo­[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and [(3aR,5R,6R,7R,7aS)-6,7-bis­(acet­yloxy)-2-oxo­octa­hydro­pyrano[3,2-b]pyrrol-5-yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives. They can easily be synthesized in a few steps from commercially available glycals. As a result of the ring strain from the four-membered rings in (I) and (II), the conformations of the carbohydrates deviate strongly from the ideal chair form. Compound (II) occurs in the boat form. In the five-membered lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair conformation. As a result of the distortion of the sugar rings, the configurations of the three bicyclic carbohydrate derivatives could not be determined from their NMR coupling constants. From our three crystal structure determinations, we were able to establish forThe title compounds, [(1R,3R,4R,5R,6S)-4,5-bis­(acet­yloxy)-7-oxo-2-oxabi­cyclo[4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acet­yloxy-7-hy­droxy­imino-2-oxobi­cyclo­[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and [(3aR,5R,6R,7R,7aS)-6,7-bis­(acet­yloxy)-2-oxo­octa­hydro­pyrano[3,2-b]pyrrol-5-yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives. They can easily be synthesized in a few steps from commercially available glycals. As a result of the ring strain from the four-membered rings in (I) and (II), the conformations of the carbohydrates deviate strongly from the ideal chair form. Compound (II) occurs in the boat form. In the five-membered lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair conformation. As a result of the distortion of the sugar rings, the configurations of the three bicyclic carbohydrate derivatives could not be determined from their NMR coupling constants. From our three crystal structure determinations, we were able to establish for the first time the absolute configurations of all new stereocenters of the carbohydrate rings.show moreshow less

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Metadaten
Author:Uwe SchildeORCiDGND, Alexandra Kelling, Sumaira Umbreen, Torsten LinkerORCiDGND
URN:urn:nbn:de:kobv:517-opus4-100833
Series (Serial Number):Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (296)
Document Type:Postprint
Language:English
Date of first Publication:2016/11/29
Year of Completion:2016
Publishing Institution:Universität Potsdam
Release Date:2016/12/16
Tag:carbohydrate deriv­atives; configuration; conformation; crystal structure
Pagenumber:6
Source:Acta Crystallographica Section E (2016) Nr. 72, S. 1839-1844. - DOI: 10.1107/S2056989016018727
Funder:Universität Potsdam, Publikationsfonds
Grant Number:PA 2016_43
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
Peer Review:Referiert
Publication Way:Open Access
Licence (German):License LogoCreative Commons - Namensnennung, 2.0 UK
Notes extern:Bibliographieeintrag der Originalveröffentlichung/Quelle