An ethyl lactate derivative of p-tert-butylcalix[4]arene is able to differentiate the NMR spectra of 3,5-dinitrobenzoyl derivatives of amino acids methyl esters. The origin of enantiodiscrimination in solution was investigated by NMR spectroscopy and comparison with model chiral auxiliaries. (c) 2007 Elsevier Ltd. All rights reserved.
Chiral lactic acid and ethyl lactate p-tert-butylcalix[4]arene derivatives
作者:Márcio Lazzarotto、Francine F. Nachtigall、Ivo Vencato、Faruk Nome
DOI:10.1039/a702794j
日期:——
reacted with p-tert-butylcalix[4]arene in K2CO3–acetone with inversion of configuration on the asymmetric centre, and only the bis-substitution product on the distal oxygens was obtained. Further attempts to react the bis(lactate) p-tert-butylcalix[4]arene derivative with BrCH2CO2CH3 under the same conditions failed. X-Ray analysis of the lactate derivative shows two independent molecules in the unit cell;
(S)-(-)- O-甲苯磺酸硬脂酸酯与K 2 CO 3-丙酮中的对-叔丁基杯[4]芳烃反应,在不对称中心构型反转,仅末端氧上有双取代产物获得了。进一步尝试以使该双(乳酸)p -叔-butylcalix [4]芳烃衍生物与BRCH 2 CO 2 CH 3未能在相同条件下。乳酸衍生物的X射线分析显示,晶胞中有两个独立的分子;一个CH 3乙基的一半被浸没在另一个分子的空腔中。两者均采用略微扭曲的圆锥构象。NMR分析表明,亚甲基桥和间位的碳和氢是非对映体的。进行酯水解而没有外消旋化,并且保持了乳酸衍生物的非对映异构行为。