Resumen de Lower rim p-tert-butylcalix[4]arene derivatives containing galactitol pendants: Complexation of 5,11,17,23-tetrakis-(1,1-dimethylethyl)-25,27-dihydroxy -26,28-bis-2-n-(1-deoxy-d-galactityl)-aminoethoxycalix[4]arene with pb(ii) and f(-i)
Pablo J Caceres, Juan Costamagna, Angela Danil de Namor, Betty Matsuhiro
Reductive amination of D-galactose with the bisubstituted p-tert-butylcalix[4]arylethylamine in the presence of sodium cyanoborohydride allowed the introduction of one or two galactitol residues as pendants on the lower rim. The bisubstituted secondary amine, 5,11,17,23-tetrakis-(1,1-dimethylethyl)-25,27-dihydroxy-26,28-bis-2-N-(1-deoxy-D-galactityl)-aminoethoxycalix[4]arene (III) was obtained in 24.1% yield. Complexation of this compound with Pb (II) and F(-I) was studied by ¹H-NMR and spectrophotometric titration in acetonitrile, showing a stoichiometry of 1:2 (ligand:ion) with equilibrium constants of log K1=2.22 ± 0.08 and log K2=2.07 ± 0.07 for Pb(II), and log K1=1.21 ± 0.05 and log K2=1,17 ± 0.04 for F (-I) ion
