title: A complete series of 6-deoxy-monosubstituted tetraalkylammonium derivatives of α-, β-, and γ-cyclodextrin with 1, 2, and 3 permanent positive charges.
abstract: An efficient synthetic route toward the preparation of a complete series of monosubstituted tetraalkylammonium cyclodextrin (CD) derivatives is presented. Monotosylation of native CDs (α-, β-, γ-) at position 6 gave the starting material. Reaction of monotosylate (mono-Ts-CD) with 45% aqueous trimethylamine gave CDs substituted with one cationic functional group in a single step. Derivatives equipped with a substituent containing two cationic sites separated by an ethylene or a propylene linker were prepared by reacting mono-Ts-CD with neat N,N,N'-trimethylethane-1,2-diamine or N,N,N'-trimethylpropane-1,3-diamine and subsequent methylation by CH3I in good yields. Finally, analogues bearing a moiety with three tetraalkylammonium sites were synthesized by reacting mono-Ts-CD with bis(3-aminopropyl)amine and subsequent methylation. The majority of the presented reactions are very straightforward with a simple work-up, which avoids the need of chromatographic separation. Thus, these reactions are suitable for the multigram-scale production of monosubstituted cationic CDs.
authors.affiliation: Department of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40, Prague 2, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Popr
authors.affiliation: Department of Teaching and Didactics of Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40, Prague 2, Czech Republic.
authors.forename: Simona
authors.initials: S
authors.lastname: Hybelbauerová
authors.affiliation: Department of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 40, Prague 2, Czech Republic.
authors.forename: Jindřich
authors.initials: J
authors.lastname: Jindřich
keywords: cationic; cyclodextrins; monosubstitution; regioselectivity; tetraalkylammonium derivatives