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 for theThe 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.…
Author details: | Uwe SchildeORCiDGND, Alexandra Kelling, Sumaira Umbreen, Torsten LinkerORCiDGND |
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DOI: | https://doi.org/10.1107/S2056989016018727 |
ISSN: | 2056-9890 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/27980845 |
Title of parent work (English): | Acta crystallographica, Section E, Crystallographic communications |
Publisher: | International Union of Crystallography |
Place of publishing: | Chester |
Publication type: | Article |
Language: | English |
Year of first publication: | 2016 |
Publication year: | 2016 |
Release date: | 2020/03/22 |
Tag: | carbohydrate derivatives; configuration; conformation; crystal structure |
Volume: | 72 |
Number of pages: | 27 |
First page: | 1839 |
Last Page: | + |
Funding institution: | University of Potsdam; Deutsche Forschungsgemeinschaft |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
Peer review: | Referiert |