title: Crystal structures of heptakis(2,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose, heptakis(2-O-methyl-3,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose and heptakis(2-O-methyl)cyclomaltoheptaose.
abstract: Crystal structures of heptakis(2,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose, heptakis(2-O-methyl-3,6-di-O-tert-butyldimethylsilyl)cyclomaltohep taose and heptakis(2-O-methyl)cyclomaltoheptaose were determined from X-ray diffraction patterns obtained for single crystals of the title compounds grown from ethyl acetate and ethanol, respectively, as solvent. The crystal structures prove conclusively that quantitative migration of the tert-butyldimethylsilyl group from the 2-O- to the 3-O-position [D. Icheln, B. Gehrcke, Y. Piprek, P. Mischnick, W.A. Konig, M.A. Dessoy, A.F. Morel, Carbohydr. Res., 280 (1996) 237-250] was achieved during methylation of heptakis(2,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose by iodomethane-sodium hydride.
authors.affiliation: Department of Chemistry, Texas A&M University, College Station 77842-3012, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Reibenspies
authors.forename: D K
authors.initials: DK
authors.lastname: Maynard
authors.forename: A
authors.initials: A
authors.lastname: Derecskei-Kovacs
authors.forename: G
authors.initials: G
authors.lastname: Vigh
mesh_terms: D003461:Crystallography; D018360:Crystallography, X-Ray; D003505:Cyclodextrins / Q000737:chemistry*; D005503:Food Additives / Q000737:chemistry; D008745:Methylation; D008958:Models, Molecular; D015394:Molecular Structure; D047392:beta-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D005503:Food Additives; D047392:beta-Cyclodextrins; C422168:heptakis(2,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose; C422170:heptakis(2-O-methyl)cyclomaltoheptaose; C422169:heptakis(2-O-methyl-3,6-di-O-tert-butyldimethylsilyl)cyclomaltoheptaose; C031215:betadex