Heterocalixarenes. Part 2. Calix[m]uracil[n]benzimidazol-2(1H)-one[3] arenes: synthesis and binding characteristics

Abstract

The reactions of uracil/benzimidazol-2(1H)-one with 1,3-bis(bromomethyl)benzene provide respectively1 3-bis[(3-bromomethylbenzene)methyl]uracil/benzimidazol-2(1H)-onewhich on subsequent cyclization with1,3-bis[(uracil-1-yl/benzimidazol-2(1H)-one-1-yl)methyl]benzenederivatives provide respectively calix[m]uracil[n]benzimidazoI-2(1H)-one[3]arenes[m =3, n = 0 (9); m = 2, n = 1 (10);m = 1, n = 2 (11) and m = 0, n = 3 (12)]. The heterocalixarenes 9-12, both in liquid-liquid and solid-liquid extraction experiments, selectively extract ammonium picrates over the similarly sized K⁺ picrate. The selectivity is much more pronounced in the case of solid-liquid extractions. Both in L-L and S-L extractions, 10 exhibits the highest order oft-BuNH₃⁺/K⁺ selectivity.