通过片段缩合已经制备了几种在对位具有三个或四个不同取代基的手性杯[4]芳烃。标准的衍生化程序总是导致形成各种构象异构体的混合物,仅通过制备型HPLC可以从中分离出圆锥构象的衍生物。对于四酯衍生物,通过二维1 H NMR光谱显示,由于取代基的不同,其圆锥构象强烈扭曲。然而,该四酯的钠络合物再次呈现规则的锥构型。
Structure of 5,17-dimethyl-11,23-dioctylcalix[4]arene
摘要:
The title compound C46O4H60 crystallizes in the triclinic space group, P1 bar, with a = 11.584(2), b = 16.261(2), c = 11.172(1) angstron, alpha = 103.15(8), beta = 95.68(1), gamma = 96.85(1)-degrees. The structure was solved by direct methods, and refined by weighted full-matrix least squares to R = 0.097. This is the second calix[4]arene with two different alkyl substituents at para positions of the phenolic rings. The macrocycle adopts the cone conformation. Interactions CH3-pi are established between two calixarenes related by a center of symmetry. Comparisons are made between the conformation of this molecule and that of symmetrically substituted calix[4]arenes.
Asymmetric calix(4)arenes (5) consisting of three different phenolic units were obtained by fragment condensation either of a trinuclear compound (1) with a 2,6-bis(bromomethyl)phenol (2) or a dinuclear compound (3) with a bisbromomethylated dimer (4) in a dioxane–TiCl4 system.