A new class of cationic cyclodextrins: synthesis and chemico-physical properties

Abstract

A new class of positively charged triazole-bridged b-cyclodextrin (b-CD) derivatives have been synthesized in excellent yields (over 70%) through a copper-catalyzed azide-alkyne cycloaddition (CuAAC), starting from 6 I -azido-6 I -deoxy-b-CD or its permethylated derivative and a series of 1-butyl-3-alkynylimidazolium salts. The regioselective azide/alkyne [3 + 2] cycloaddition was efficiently carried out using metallic copper as the catalyst, affording very clean products. Easy access to such hybrid molecules that combine the properties of CDs and ionic liquids, may pave the way to a number of new applications in analytical chemistry and catalysis.

Insertion of a Single‐Molecule Magnet inside a Ferromagnetic Lattice Based on a 3D Bimetallic Oxalate Network: Towards Molecular Analogues of Permanent Magnets

“…As concerns the permethylated mono‐6‐ O ‐modified CDs, the tosyl group is the most popular protecting group of 6‐OH 3a. 31 Tosylate groups located on the C‐6 position in mono‐6‐ O ‐tosyl CD derivatives have been used repeatedly as leaving groups for nucleophilic substitutions, but displacement of the tosylate group requires good nucleophiles, high temperatures, and long reaction times, which yield several byproducts and relatively low yields of the desired monosubstituted compounds 31b.…”

Enabling technologies and green processes in cyclodextrin chemistry

“…Recently the preparation of a large number of CD-derivatives by MW-assisted CuAAC regioselective cycloadditions has been described. A selected series of derivatives are depicted in Scheme 10 : CD-acryloyl derivative [ 60 – 61 ], β-CD/dye derivatives [ 31 , 62 – 64 ], CD-ionic liquid hybrids [ 65 – 66 ], CD-based iminosugar conjugates [ 67 ], water-soluble CD homo- and heterodimers [ 68 – 69 ], trimers [ 70 – 71 ] and oligomers [ 72 ] of α-, β- and γ-CD have all been successfully produced. This wide variety of compounds was obtained in good to excellent yield under MW irradiation (from 20 min to 3 h at 75 °C to 100 °C).…”

The Combined Use of Microwaves and Ultrasound: Methods and Practice

“…Again, one-pot protocols could be applied which lead to products in high yields (>80%) within 2-3 h. This contrasts favorably with results attained in oil baths (poorer yields after 6-10 h). Extensions to sensitive molecules bearing other functional groups, such as cyclodextrins, have also been successful [63] and include the preparation of cyclodextrins that incorporate side chains of triazole-imidazolium units which exhibit IL properties [64] (Scheme 13.9). It is noteworthy that the functionalization of cyclodextrin derivatives had been achieved previously under the combined activation of MW and US [65].…”