Synthesis of Tripeptide Derivatives with Three Stereogenic Centers and Chiral Recognition Probed by Tetraaza Macrocyclic Chiral Solvating Agents Derived from d -Phenylalanine and (1S,2S)-(+)-1,2-Diaminocyclohexane via 1H NMR Spectroscopy
| Autor: | Lei Feng, Jiaxin Zhang, Hongmei Zhao, Lin Ai, Pericles Stavropoulos, Guangpeng Gao, Li Zheng, Yu Wang |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | The Journal of Organic Chemistry. 83:13874-13887 |
| ISSN: | 1520-6904 0022-3263 |
| DOI: | 10.1021/acs.joc.8b02212 |
| Popis: | Enantiomers of a series of tripeptide derivatives with three stereogenic centers (±)-G1-G9 have been prepared from d- and l-α-amino acids as guests for chiral recognition by 1H NMR spectroscopy. In the meantime, a family of tetraaza macrocyclic chiral solvating agents (TAMCSAs) 1a-1d has been synthesized from d-phenylalanine and (1 S,2 S)-(+)-1,2-diaminocyclohexane. Discrimination of enantiomers of (±)-G1-G9 was carried out in the presence of TAMCSAs 1a-1d by 1H NMR spectroscopy. The results indicate that enantiomers of (±)-G1-G9 can be effectively discriminated in the presence of TAMCSAs 1a-1d by 1H NMR signals of multiple protons exhibiting nonequivalent chemical shifts (ΔΔδ) up to 0.616 ppm. Furthermore, enantiomers of (±)-G1-G9 were easily assigned by comparing 1H NMR signals of the split corresponding protons with those attributed to a single enantiomer. Different optical purities (ee up to 90%) of G1 were clearly observed and calculated in the presence of TAMCSAs 1a-1d, respectively. Intermolecular hydrogen bonding interactions were demonstrated through theoretical calculations of enantiomers of (±)-G1 with TAMCSA 1a by means of the hybrid functional theory with the standard basis sets of 3-21G of the Gaussian 03 program. |
| Databáze: | OpenAIRE |
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