Inter- and intramolecular Mitsunobu reaction and metal complexation study: synthesis of S-amino acids derived chiral 1,2,3,4-tetrahydroquinoxaline, benzo-annulated [9]-N3 peraza, [12]-N4 peraza-macrocycles
作者:Krishnananda Samanta、Nitin Srivastava、Satyen Saha、Gautam Panda
DOI:10.1039/c1ob06304a
日期:——
Substituted 1,2,3,4-tetrahydroquinoxaline, benzo-annulated unsymmetrical chiral [9]-N3 peraza, and [12]-N4 peraza-macrocycles have been synthesized employing an inter- and intramolecular Mitsunobu reaction from an amino acid derived common synthetic intermediate 3. The metal complexation study of these macrocycles has been investigated by UV-visible spectroscopic technique with binding constant (Kb) value 1.84 × 103 dm3 mol−1 using the Benesi–Hildebrand equation and a Gibbs free energy (ΔG) −19.4 kJ mol−1 at 35 °C for 14d with Co2+. The binding properties of the metal were dependent on the structure of polyaza-macrocycles that were confirmed by the DFT optimized structure of two macrocycles. A detailed investigaton of UV-visible spectra of macrocycles and their complete interpretation with the help of TD-DFT along with the frontier molecular orbital calculations are presented.
合成了替代的1,2,3,4-四氢喹喔啉、苯环附加的不对称手性[9]-N3佩拉扎和[12]-N4佩拉扎大环,采用分子间和分子内的Mitsunobu反应,从氨基酸衍生的共同合成中间体3开始。这些大环的金属配位研究通过紫外-可见光谱技术进行,结合常数(Kb)值为1.84 × 10^3 dm^3 mol−1,使用Benesi–Hildebrand方程,并在35°C下,14天内对于Co2+的吉布斯自由能(ΔG)为-19.4 kJ mol−1。金属的结合特性依赖于聚氮大环的结构,这一点通过DFT优化的两个大环的结构得到确认。详细探讨了大环的紫外-可见光谱及其完整解释,并借助TD-DFT以及前沿分子轨道计算进行了分析。