Calix[4]arenes bearing one or two methylenebisphosphonic acid fragments were prepared via addition of diethylphosphite to the parent calix[4]arene aldehydes. The resulting compounds displayed stronger inhibition of calf intestine alkaline phosphatase than simple methylenebisphosphonic or 4-hydroxyphenyl methylenebisphosphonic acids. The action of these phosphorylated calix[4]arenes is concordant with partial mixed-type inhibition. The inhibition constants Ki and Ki' for the calix[4]arene bis(methylenebisphosphonic) acid in Tris-HCl buffer at pH 9 are 0.38 microM and 2.8 microM respectively. The replacement of the phosphoric acid moieties on the macrocycle with diethylphosphonates results in a sharp decrease of its inhibitory action. Preorganizing phosphonic acid fragments using a calixarene platform therefore provides a promising approach for the design of efficient alkaline phosphatase inhibitors.

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[structure: see text] Chiral calix[4]arene alpha-aminophosphonic acids were obtained through diastereoselective Pudovik-type addition of sodium ethyl phosphites to the chiral calixarene imines, removal of chiral auxiliary groups, and mild dealkylation of phosphonate fragments. The diacids obtained show inhibitory activity toward porcine kidney alkaline phosphatase that depends considerably on the absolute configuration of the alpha-carbon atoms.

Host-Guest complexation of calixarene-bis-hydroxymethylenediphosphonic acid with 17 amino acids in water solution had been studied by the RP HPLC and molecular modelling methods. It had been shown the binding constants of the complexes are depended on the nature of the amino acid residue, log P and pKa of the acids. The complexation is mainly determined by the electrostatic interactions between the positively charged nitrogen atom of the amino acid and the negatively charged oxygen atom of phosphonic acid residue of the calixarene, the Host-Guest p-p, СН-p and solvophobic interactions.

Two novel amphiphilic phosphorylated-calix- [4]-arenes, 5,11,17,23-tetrakis(dihydroxyphosphonyl)-25,-26,27,28-tetradecyloxy-calix-[4]-arene and 5,11,17,23-tetrakis(dihydroxyphosphonyl)-25,26,27,28-tetradodecyloxy-calix-[4]-arene, have been synthesized, and their interactions with the cations Na + , K + , Mg 2+ , and Ca 2+ have been measured at varying concentrations of the chloride salts. The systems were studied both at the air-water interface and in aqueous suspension as colloidal nanostructures. In the Langmuir experiments, monolayer expansion and increase in collapse pressure were observed for Na + at a concentration of 145 mM. For Mg 2+ , there was monolayer expansion accompanied by the formation of a second phase at a subphase concentration of 30 mM. In contrast, in the case of Ca 2+ there is an apparent contraction of the monolayer. The nanostructures were imaged by means of atomic force microscopy in the noncontact mode. As aqueous dispersions, no change in size or stability of the colloidal systems was observed with the monovalent cations; however, for the divalent cations at concentrations above 3 mM for Mg 2+ and 3 mM for Ca 2+ there is aggregation and flocculation of the dispersions.

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