Chiral mono- and dicarbamates derived from ethyl (<i>S</i>)-lactate: convenient chiral solvating agents for the direct and efficient enantiodiscrimination of amino acid derivatives by <sup>1</sup>H NMR spectroscopy

Balzano, Federica; Barretta, Gloria Uccello

doi:10.1039/d0ra00200c

Cited by 8 publications

(3 citation statements)

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“…Deuterated chloroform (CDCl 3 ) used for the NMR analysis was acquired by Deutero GmbH. Derivatives 1 – 5 and 9 – 13 were prepared as described in refs ( 33 ) and ( 25 ), respectively. The NMR characterization is reported in ref ( 25 ).…”

Section: Methodsmentioning

confidence: 99%

A Dimeric Thiourea CSA for the Enantiodiscrimination of Amino Acid Derivatives by NMR Spectroscopy

et al. 2021

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The reaction of benzoyl isothiocyanate with (1 R ,2 R )-1,2-bis(2-hydroxyphenyl)ethylenediamine afforded a new thiourea chiral solvating agent (CSA) with a very high ability to differentiate 1 H and 13 C NMR signals of simple amino acid derivatives, even at low concentrations. The enantiodiscrimination efficiency was higher with respect to that of the parent monomer, a thiourea derivative of 2-((1 R )-1-aminoethyl)phenol, thus putting into light the relevance of the cooperativity between the two molecular portions of the dimer in a cleft conformation stabilized by interchain hydrogen bond interactions. An achiral base additive (DABCO or DMAP) played an active role in the chiral discrimination processes, mediating the interaction between the CSA and the enantiomeric mixtures. The chiral discrimination mechanism was investigated by NMR spectroscopy through the determination of complexation stoichiometries, association constants, and the stereochemistry of the diastereomeric solvates.

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Section: Methodsmentioning

confidence: 99%

A Dimeric Thiourea CSA for the Enantiodiscrimination of Amino Acid Derivatives by NMR Spectroscopy

et al. 2021

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“…Tetrahydrofuran (THF) was distilled from sodium. Derivative 10 and derivatives 5 – 9 , 11 – 17 were prepared as described in refs , , respectively.…”

Section: Methodsmentioning

confidence: 99%

Thiourea Derivative of 2-[(1R)-1-Aminoethyl]phenol: A Flexible Pocket-like Chiral Solvating Agent (CSA) for the Enantiodifferentiation of Amino Acid Derivatives by NMR Spectroscopy

et al. 2020

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Thiourea derivatives of 2-[(1 R )-1-aminoethyl]phenol, (1 S ,2 R )-1-amino-2,3-dihydro-1 H -inden-2-ol, (1 R ,2 R )-(1 S ,2 R )-1-amino-2,3-dihydro-1 H -inden-2-ol, and ( R )-1-phenylethanamine have been compared as chiral solvating agents (CSAs) for the enantiodiscrimination of derivatized amino acids using nuclear magnetic resonance (NMR) spectroscopy. Thiourea derivative, prepared by reacting 2-[(1 R )-1-aminoethyl]phenol with benzoyl isothiocyanate, constitutes an effective CSA for the enantiodiscrimination of N- 3,5-dinitrobenzoyl (DNB) derivatives of amino acids with free or derivatized carboxyl functions. A base additive 1,4-diazabicyclo[2.2.2]octane(DABCO)/ N , N -dimethylpyridin-4-amine (DMAP)/NBu 4 OH) is required both to solubilize amino acid derivatives with free carboxyl groups in CDCl 3 and to mediate their interaction with the chiral auxiliary to attain efficient differentiation of the NMR signals of enantiomeric substrates. For ternary systems CSA/substrate/DABCO, the chiral discrimination mechanism has been ascertained through the NMR determination of complexation stoichiometry, association constants, and stereochemical features of the diastereomeric solvates.

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“…3,5-Disubstituted phenylcarbamate moieties, bearing π-clouds, HB acceptor, and HB donor sites, have been introduced in a series of CSAs; this structural element also characterizes some widely used polysaccharide-based CSPs and other CSs. , Focusing on the ethyl lactate scaffold, Balzano and Uccello-Barretta reported the preparation of compound 68 , in which the primary hydroxyl is carbamoylated, compounds 69 and 70 , as diastereomeric derivatives bearing an additional chiral center, and compounds 71 – 73 , containing an additional π-acid 3,5-dinitrophenyl moiety on the secondary hydroxyl . The enantiorecognition efficiency of these compounds was verified towards N -3,5-dinitrobenzoyl derivatives of amino acid methyl esters.…”

Section: Trends In Enantioselective Recognition In Natural and Synthe...mentioning

confidence: 99%

Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers

2022

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It is not a coincidence that both chirality and noncovalent interactions are ubiquitous in nature and synthetic molecular systems. Noncovalent interactivity between chiral molecules underlies enantioselective recognition as a fundamental phenomenon regulating life and human activities. Thus, noncovalent interactions represent the narrative thread of a fascinating story which goes across several disciplines of medical, chemical, physical, biological, and other natural sciences. This review has been conceived with the awareness that a modern attitude toward molecular chirality and its consequences needs to be founded on multidisciplinary approaches to disclose the molecular basis of essential enantioselective phenomena in the domain of chemical, physical, and life sciences. With the primary aim of discussing this topic in an integrated way, a comprehensive pool of rational and systematic multidisciplinary information is provided, which concerns the fundamentals of chirality, a description of noncovalent interactions, and their implications in enantioselective processes occurring in different contexts. A specific focus is devoted to enantioselection in chromatography and electromigration techniques because of their unique feature as “multistep” processes. A second motivation for writing this review is to make a clear statement about the state of the art, the tools we have at our disposal, and what is still missing to fully understand the mechanisms underlying enantioselective recognition.

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Chiral mono- and dicarbamates derived from ethyl (S)-lactate: convenient chiral solvating agents for the direct and efficient enantiodiscrimination of amino acid derivatives by ¹H NMR spectroscopy

Abstract: New lactate-based CSAs for 1H NMR enantiodifferentiation of amino acid derivatives.

Cited by 8 publications

References 20 publications

A Dimeric Thiourea CSA for the Enantiodiscrimination of Amino Acid Derivatives by NMR Spectroscopy

A Dimeric Thiourea CSA for the Enantiodiscrimination of Amino Acid Derivatives by NMR Spectroscopy

Thiourea Derivative of 2-[(1R)-1-Aminoethyl]phenol: A Flexible Pocket-like Chiral Solvating Agent (CSA) for the Enantiodifferentiation of Amino Acid Derivatives by NMR Spectroscopy

Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers

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Chiral mono- and dicarbamates derived from ethyl (S)-lactate: convenient chiral solvating agents for the direct and efficient enantiodiscrimination of amino acid derivatives by 1H NMR spectroscopy

Abstract: New lactate-based CSAs for 1H NMR enantiodifferentiation of amino acid derivatives.

Cited by 8 publications

References 20 publications

A Dimeric Thiourea CSA for the Enantiodiscrimination of Amino Acid Derivatives by NMR Spectroscopy

A Dimeric Thiourea CSA for the Enantiodiscrimination of Amino Acid Derivatives by NMR Spectroscopy

Thiourea Derivative of 2-[(1R)-1-Aminoethyl]phenol: A Flexible Pocket-like Chiral Solvating Agent (CSA) for the Enantiodifferentiation of Amino Acid Derivatives by NMR Spectroscopy

Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers

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Chiral mono- and dicarbamates derived from ethyl (S)-lactate: convenient chiral solvating agents for the direct and efficient enantiodiscrimination of amino acid derivatives by ¹H NMR spectroscopy