Trimerization of β-cyclodextrin through the click reaction

Triprop-2-ynyl benzene-1,3,5-tricarboxylate (A) is synthesized by the reaction of 1,3,5-benzenetricarbonyl trichloride with propargyl alcohol and (A) is clicked with mono-6-deoxy-6-azido-β-cyclodextrin (N3-β-CD) in the presence of copper(I) bromide catalyst. N3-β-CD has been prepared from β-cyclodextrin (β-CD) on treatment with toluenesulfonyl chloride (TsCl) and then with sodium azide (NaN3) in two consecutive steps. Further trimer of β-CD is characterized by 1H NMR and FTIR studies. Solubility of β-cyclodextrin (β-CD) in water can be increased by increasing the number of alcoholic OH functionalities and hydrophobic cavities in a molecule by the trimerization of β-CD.