- Structural reassignment, absolute configuration, and conformation of hypurticin, a highly flexible polyacyloxy-6-heptenyl-5,6-dihydro-2H-pyran-2-one
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The structural reassignment, absolute configuration, and conformational behavior of the highly flexible natural product hypurticin (pectinolide E), 6S-[3′S,5′R,6′S-triacetoxy-1Z-heptenyl]-5S-acetoxy-5, 6-dihydro-2H-pyran-2-one (1), were ascertained by a m
- Mendoza-Espinoza, Jose Alberto,Lopez-Vallejo, Fabian,Fragoso-Serrano, Mabel,Pereda-Miranda, Rogelio,Cerda-Garcia-Rojas, Carlos M.
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experimental part
p. 700 - 708
(2009/12/24)
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- Structural studies of the O-specific side-chain of the lipopolysaccharide from Escherichia coli O 55.
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The structure of the O-specific side-chains of the lipopolysaccharide from Escherichia coli O 55 has been investigated, methylation analysis, specific degradations, and n.m.r. spectroscopy being the principal methods used. It is concluded that the O-specific side-chains are composed of pentasaccharide repeating-units having the following structure [where Col stands for colitose (3,6-dideoxy-L-xylo-hexose)].(See formula in text).
- Lindberg,Lindh,Loenngren
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p. 105 - 112
(2007/10/02)
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- Total synthesis of 3-deoxy and 3,6-dideoxy-dl-hexoses
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Synthesis of stereoisomeric 3-deoxy-hexoses 24-27 and 3,6-dideoxy-hexoses 28-31 is reported. Butyl (E)-2,6-dihydroxy-hex-4-enoate (2) was used as the starting material for the synthesis of 3-deoxy-hexoses. For the synthesis of 3,6-dideoxy-hexoses, butyl (E)-2-acetoxy-hex-4-enoate (7) was employed. The synthesis involved the following successive steps: cis or trans hydroxylation of the double bond in 2 or 7, lactonisation of the resulting aldonic acid esters followed by acetylation and chromatographical separation of γ-lactones, reduction of lactones 16-23 to lactols with disiamylborane, and acetylation of lactols to free sugars. All compounds were obtained as pure diastereomers in racemic form.
- Chmielewski, Marek
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p. 2345 - 2352
(2007/10/02)
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