Regioselective synthesis of calixcrowns derived from p-tert-butylcalix[5]arene
摘要:
Alkylation of p-tert-butylcalix[5]arene with oligoethylene glycol-ditosylates in the presence of CsF affords the 1,3-bridged calix[5]crowns la-c in 51 to 72% yield. In the case of hexaethylene glycol the isomeric 1,2-bridged calix[5]crown-7 2c was obtained additionally. The calixcrowns were further modified by alkylation of the remaining hydroxyl groups.
Crown ether derivatives of calix[5]arenes: synthesis and complexation properties
作者:Françoise Arnaud-Neu、Ralf Arnecke、Volker Böhmer、Stefano Fanni、James L. M. Gordon、Marie-José Schwing-Weill、Walter Vogt
DOI:10.1039/p29960001855
日期:——
Several crownetherderivatives of calix[5]- and tert-butylcalix[5]-arene have been synthesized and converted into their trimethyl ethers as neutral ligands. For selected examples extraction studies have been carried out with alkali metal picrates in the system water–dichloromethane and stability constants have been determined by UV spectroscopy in methanol. All ligands show a more or less pronounced
作者:Salvatore Caccamese、Anna Notti、Sebastiano Pappalardo、Melchiorre F Parisi、Grazia Principato
DOI:10.1016/s0040-4020(99)00195-7
日期:1999.4
Reaction of α-picolyloxy-p-tert-butylcalix[5]arene with tri- to pentaethylene glycol ditosylates and K2CO3 regioselectively affords racemic (1,2)-bridged crown ether derivatives in the cone conformation. Their structure is firmly established by NMR spectroscopy and by comparison with appropriate (1,3)-bridged crown-6 regioisomers, synthesized by unequivocal sequences. The enantiomeric resolution of
的反应α -picolyloxy- p -叔-butylcalix [5]芳烃与三到五乙二醇ditosylates和K 2 CO 3区域选择性地得到外消旋(1,2)-bridged冠醚在锥形构象的衍生物。它们的结构是通过NMR光谱法确定的,并与通过明确序列合成的适当的(1,3)桥连的Crown-6区域异构体进行了比较。外消旋物的对映体拆分已使用对映选择性固定相通过直接HPLC分离实现。(1,2)-桥接的Crown-5衍生物的对映异构体显示出迄今为止报道的固有手性杯芳烃的最大分离因子(α)之一。
Dual binding mode of alkylammonium cations to (1,3)-calix[5]crown-6 triesters
作者:Mario Gattuso、Anna Notti、Sebastiano Pappalardo、Melchiorre F Parisi
DOI:10.1016/s0040-4039(98)00107-5
日期:1998.4
Potentially heteroditopic receptors 1c-h are easily obtained by exhaustivealkylation of (1,3)-calix[5]crown-6 triols 1a () or 1b (R′ = H) with alkyl bromoacetates. 1H NMR titration experiments provide clear evidence for a dual (endo-cavity and/or exo-cavity) binding mode of alkylammonium cations to hosts 1c-h, depending on the shape of the guest and the size of substituents at the upper rim.
通过将(1,3)-calix [5] crown-6三醇1a()或1b(R'= H)与溴代乙酸烷基酯进行完全烷基化反应,可以轻松获得潜在的异位受体1c-h。1个1 H NMR滴定实验提供明确的证据用于双(内切-cavity和/或外切-cavity)结合烷基铵阳离子的模式给主机1C-H ,这取决于客户的形状和取代基中的上边缘的大小。
Selective <i>endo</i>-Calix Complexation of Linear Alkylammonium Cations by Functionalized (1,3)-<i>p-</i><i>tert</i>-Butylcalix[5]crown Ethers