A Thiourea Derivative of 2-[(1 R )-1-Aminoethyl]phenol as a Chiral Sensor for the Determination of the Absolute Configuration of N -3,5-Dinitrobenzoyl Derivatives of Amino Acids.

Autor: Aiello F; Institute for Chemical and Physical Processes, National Research Council, Via G. Moruzzi 1, 56124 Pisa, Italy., Recchimurzo A; Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy., Balzano F; Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy., Uccello Barretta G; Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy., Cefalì F; Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy.
Jazyk: angličtina
Zdroj: Molecules (Basel, Switzerland) [Molecules] 2024 Mar 15; Vol. 29 (6). Date of Electronic Publication: 2024 Mar 15.
DOI: 10.3390/molecules29061319
Abstrakt: In the exploration of chiral solvating agents (CSAs) for nuclear magnetic resonance (NMR) spectroscopy designed for the chiral analysis of amino acid derivatives, notable advancements have been made with thiourea-CSAs. 1-TU , derived from 2-[(1 R )-1-aminoethyl]phenol and benzoyl isothiocyanate, is effective in the enantiodifferentiation of N -3,5-dinitrobenzoyl ( N -DNB) amino acids. In order to broaden the application of 1-TU for configurational assignment, enantiomerically enriched N -DNB amino acids were analyzed via NMR. A robust correlation was established between the relative position of specific 1 H and 13 C NMR resonances of the enantiomers in the presence of 1-TU . 1,4-Diazabicyclo[2.2.2]octane (DABCO) was selected for the complete solubilization of amino acid substrates. Notably, the para and ortho protons of the N -DNB moiety displayed higher frequency shifts for the ( R )-enantiomers as opposed to the ( S )-enantiomers. This trend was consistently observed in the 13 C NMR spectra for quaternary carbons bonded to NO 2 groups. Conversely, an inverse correlation was noted for quaternary carbon resonances of the carboxyl moiety, amide carbonyl, and methine carbon at the chiral center. This observed trend aligns with the interaction mechanism previously reported for the same chiral auxiliary. The configurational correlation can be effectively exploited under conditions of high dilution or, significantly, under sub-stoichiometric conditions.
Databáze: MEDLINE
Externí odkaz:
Nepřihlášeným uživatelům se plný text nezobrazuje