Interglycosidic acetals. Part 3. Synthesis and structure determination of cyclic monobenzylidene acetals of cyclodextrin derivatives bridging between two contiguous D-glucopyranosyl residues.
Transacetalation of fully 6-O-pivaloylated alpha-, beta-, and gamma-cyclodextrins with benzaldehyde dimethylacetal in the presence of (+)-10-camphorsulfonic acid gave monobenzylidene acetals (4, 5, 6) in moderately good yields. Benzylation of the beta-cyclodextrin derivative 5 followed by acid-catalyzed hydrolysis of the benzylidene group and acetylation afforded a di-O-acetyl-non-adeca-O-benzyl derivative 9. NMR spectroscopic analysis of 9, including two-dimensional HOHAHA and 1H-(13)C correlation experiments revealed that the benzylidene group bridged the O-2 and O-3 positions of contiguous D-glucopyranosyl residues. Reductive ring-opening of the benzylidene acetal with lithium aluminum hydride/aluminum chloride afforded predominantly a 2(1)-O-unprotected derivative 10 in good yield.
Sakairi
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N
Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Japan.
Nishi
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N
Tokura
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S
Kuzuhara
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H
D000080:Acetals / Q000138:chemical synthesis* / Q000737:chemistry; D002240:Carbohydrate Sequence; D003505:Cyclodextrins / Q000138:chemical synthesis* / Q000737:chemistry; D005947:Glucose / Q000031:analogs & derivatives; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure
D000080:Acetals; D003505:Cyclodextrins; D005947:Glucose