The effect of urea moiety in amino acid binding by β-cyclodextrin derivatives: A 1000-fold increase in efficacy comparing to native β-cyclodextrin.
Water soluble amphiphilic anion receptors based on urea-substituted β-cyclodextrin were synthesized via a copper(I) mediated azide-alkyne coupling reaction. The synthetic route was designed to minimize the number of operations of cyclodextrins. Stable products were obtained in 90% yield. They were successfully tested as amino acid receptors, showing excellent affinity constants (103-104M-1) in a highly competitive environment (pH 8 phosphate-buffered water solution). Isothermal titration calorimetry indicated that complex formation strongly depends on the hydrophobic nature of the guest and that the urea moiety of the receptor is necessary to efficiently bind amino acids.
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
Pawel
P
Stepniak
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland; Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
Bruno
B
Lainer
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
Kazimierz
K
Chmurski
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland. Electronic address: jurczak_group@icho.edu.pl.
Janusz
J
Jurczak
Amino acids; Azide-alkin coupling; Calorimetry; Complexes; Cyclodextrin; Host-guest chemistry