Since water is solution where most biochemical processes take place, searching of new systems interacting selectively in this environment is important. Furthermore, phosphonic acids are used as active moieties within medicines. Understanding of their role and potential as components of neurotransmitters and hormones antagonists and also enzymes and receptors inhibitors [1] is becoming clearer. As we know that the receptor-ligand recognition processes rely on mutual structural relationship of both interacted molecules and that hydrophobic effect is becoming important phenomena in polar solvents, we have obtained a synthetic calixarene-based receptors 1, 2 which possess four phosphonic acids groups as well as hydrophobic cavity. Complexation processes of the amines, aminoalkohols [2] and aminoacids methyl esters by the compound 1 in water were examined. Herein we demonstrate the synthesis and inclusion properties of the tetraphosphorylated calix[4]arene 2 towards six aminoacids methyl esters, which are shown below. The complexes formation processes and their stoichiometry were studied by ¹H NMR spectroscopy in phosphate buffered deuterated water at pD 7.3. Chemical shifts induced by association process indicate selective inclusion these of the methyl ester aminoacids molecules which have ammonium, guanidinium or imidazolium group at the end of side chain. Possible modes of formed complexes will be discussed.

1. R = CH₃CH₂CH₂
2. R = H

Acknowledgements: This work is supported by KBN (grant 3 T09A 141 29).

[1] J.-Y. Winum, A. Innocenti, V. Gagnard, J.-L. Montero, A. Scozzafava, D. Vullo, C. T. Supuran, Bioorg. Med. Chem. Lett. 2005, 15, 1683-1686.

[2] D. Witt, J. Dziemidowicz, J. Rachoń, Heteroatom Chem. 2004, 15, 155-161.

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