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Article: Achiral cycledextrin analogues

TitleAchiral cycledextrin analogues
Authors
KeywordsAnalogues
Carbohydrates
Cyclodextrin
Cyclooligomerizations
Glycosylations
Nan ostructures
Issue Date1997
Citation
Chemistry - A European Journal, 1997, v. 3, n. 8, p. 1299-1314 How to Cite?
AbstractThe synthesis of a new family of cycledextrin (CD) analogues is described. This family consists of novel cyclic oligosaccharides built from monosaccharides that possess the same relative but opposite absolute (D- and L-) configurations. The alternation of such D- and L-residues-specifically, D- and L-rhamnose or D- and L-mannose-in a macrocyclic structure results in S(n)-type symmetry and, consequently, optical inactivity. The synthesis of these cyclic oligosaccharides was achieved by an economical polycondensation/cycloglycosylation approach that relies on an appropriately-derivatized disaccharide monomer and that avoids the time-consuming, and often low-yielding, stepwise growth of long linear oligosaccharide precursors. In the cases reported, the key precursors are the disaccharide menumars 1-RR and 1-MM, which bear both a glycosyl donor (cyanoethylidene function) and a glycosyl acceptor (trity1oxy group). These compounds are able to undergo Tr+-catalyzed polycondensation which, under appropriate dilution conditions, can be terminated by cycloglycosylation. Thus, compound 1-RR was converted into a range of protected cyclic rhamnooligosaccharides 15-19 in 64% overall yield. All these products, including the unique cyclic dodeca- and tetradecasaccharides 18 and 19, have been isolated by preparative HPLC. Unexpectedly, treatment of the manno analogue of thedisaccharide 1-RR (compound 1-MM) under the same conditions produced only the cyclic hexasaccharide 28 and numerous apparently linear oligomers. Removal of the protecting groups from 16-19 afforded the free cyclic oligosaccharides 2124, which exhibited the predicted zero optical rotation and very simple NMR spectra, indicating highly symmetrical structures. X-ray crystallography reveals that in the solid state the cyclooctaoside 21 possesses a C2 symmetric structure, on account of a slight deformation of its cylindrical shape. The channel-type crystal packing of molecules of 21 forms nanotubes with an internal diameter of around 1 nm. Conversely, the cyclic hexasaccharide 29 possesses a C symmetric solid-state structure and its molecules pack to form a parquet-like superstructure.
Persistent Identifierhttp://hdl.handle.net/10722/332397
ISSN
2023 Impact Factor: 3.9
2023 SCImago Journal Rankings: 1.058
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorAshton, Peter R.-
dc.contributor.authorCantrill, Stuart J.-
dc.contributor.authorGattuso, Giuseppe-
dc.contributor.authorMenzer, Stephan-
dc.contributor.authorNepogodiev, Sergey A.-
dc.contributor.authorShipway, Andrew N.-
dc.contributor.authorStoddart, J. Fraser-
dc.contributor.authorWilliams, David J.-
dc.date.accessioned2023-10-06T05:11:09Z-
dc.date.available2023-10-06T05:11:09Z-
dc.date.issued1997-
dc.identifier.citationChemistry - A European Journal, 1997, v. 3, n. 8, p. 1299-1314-
dc.identifier.issn0947-6539-
dc.identifier.urihttp://hdl.handle.net/10722/332397-
dc.description.abstractThe synthesis of a new family of cycledextrin (CD) analogues is described. This family consists of novel cyclic oligosaccharides built from monosaccharides that possess the same relative but opposite absolute (D- and L-) configurations. The alternation of such D- and L-residues-specifically, D- and L-rhamnose or D- and L-mannose-in a macrocyclic structure results in S(n)-type symmetry and, consequently, optical inactivity. The synthesis of these cyclic oligosaccharides was achieved by an economical polycondensation/cycloglycosylation approach that relies on an appropriately-derivatized disaccharide monomer and that avoids the time-consuming, and often low-yielding, stepwise growth of long linear oligosaccharide precursors. In the cases reported, the key precursors are the disaccharide menumars 1-RR and 1-MM, which bear both a glycosyl donor (cyanoethylidene function) and a glycosyl acceptor (trity1oxy group). These compounds are able to undergo Tr+-catalyzed polycondensation which, under appropriate dilution conditions, can be terminated by cycloglycosylation. Thus, compound 1-RR was converted into a range of protected cyclic rhamnooligosaccharides 15-19 in 64% overall yield. All these products, including the unique cyclic dodeca- and tetradecasaccharides 18 and 19, have been isolated by preparative HPLC. Unexpectedly, treatment of the manno analogue of thedisaccharide 1-RR (compound 1-MM) under the same conditions produced only the cyclic hexasaccharide 28 and numerous apparently linear oligomers. Removal of the protecting groups from 16-19 afforded the free cyclic oligosaccharides 2124, which exhibited the predicted zero optical rotation and very simple NMR spectra, indicating highly symmetrical structures. X-ray crystallography reveals that in the solid state the cyclooctaoside 21 possesses a C2 symmetric structure, on account of a slight deformation of its cylindrical shape. The channel-type crystal packing of molecules of 21 forms nanotubes with an internal diameter of around 1 nm. Conversely, the cyclic hexasaccharide 29 possesses a C symmetric solid-state structure and its molecules pack to form a parquet-like superstructure.-
dc.languageeng-
dc.relation.ispartofChemistry - A European Journal-
dc.subjectAnalogues-
dc.subjectCarbohydrates-
dc.subjectCyclodextrin-
dc.subjectCyclooligomerizations-
dc.subjectGlycosylations-
dc.subjectNan ostructures-
dc.titleAchiral cycledextrin analogues-
dc.typeArticle-
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1002/chem.19970030818-
dc.identifier.scopuseid_2-s2.0-0030794768-
dc.identifier.volume3-
dc.identifier.issue8-
dc.identifier.spage1299-
dc.identifier.epage1314-
dc.identifier.isiWOS:A1997XR09000015-

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