1
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Browne CA, Datta SS. Harnessing elastic instabilities for enhanced mixing and reaction kinetics in porous media. Proc Natl Acad Sci U S A 2024; 121:e2320962121. [PMID: 38980904 PMCID: PMC11260153 DOI: 10.1073/pnas.2320962121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 06/07/2024] [Indexed: 07/11/2024] Open
Abstract
Turbulent flows have been used for millennia to mix solutes; a familiar example is stirring cream into coffee. However, many energy, environmental, and industrial processes rely on the mixing of solutes in porous media where confinement suppresses inertial turbulence. As a result, mixing is drastically hindered, requiring fluid to permeate long distances for appreciable mixing and introducing additional steps to drive mixing that can be expensive and environmentally harmful. Here, we demonstrate that this limitation can be overcome just by adding dilute amounts of flexible polymers to the fluid. Flow-driven stretching of the polymers generates an elastic instability, driving turbulent-like chaotic flow fluctuations, despite the pore-scale confinement that prohibits typical inertial turbulence. Using in situ imaging, we show that these fluctuations stretch and fold the fluid within the pores along thin layers ("lamellae") characterized by sharp solute concentration gradients, driving mixing by diffusion in the pores. This process results in a [Formula: see text] reduction in the required mixing length, a [Formula: see text] increase in solute transverse dispersivity, and can be harnessed to increase the rate at which chemical compounds react by [Formula: see text]-enhancements that we rationalize using turbulence-inspired modeling of the underlying transport processes. Our work thereby establishes a simple, robust, versatile, and predictive way to mix solutes in porous media, with potential applications ranging from large-scale chemical production to environmental remediation.
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Affiliation(s)
- Christopher A. Browne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ08544
| | - Sujit S. Datta
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ08544
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2
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Miyabe K, Ishitobi A, Hiyama K, Kubotani F. Moment Analysis Method for Measurement of Reaction Equilibrium and Rate Constants by Using High-Performance Liquid Chromatography. Anal Chem 2024; 96:4553-4561. [PMID: 38457369 DOI: 10.1021/acs.analchem.3c05387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
The moment analysis method was developed for the determination of association equilibrium constant (KA) and association (ka) and dissociation (kd) rate constants of intermolecular interactions between solute and ligand molecules. They are accurately determined by using moment equations from elution peak profiles because they are measured by using high-performance liquid chromatography (HPLC) under preferable conditions that neither immobilization nor chemical modification (i.e., fluorescence labeling) of solute and ligand molecules is required. To demonstrate the effectiveness of the method, it was applied to the inclusion complex formation system between dibenzo-18-crown-6 (DB18C6) and alkaline earth metal cations, i.e., Mg2+, Ca2+, and Sr2+, as a concrete example. Because the diameter of the three metal cations is smaller than that of the inner cavity of DB18C6, the values of KA, ka, and kd were analytically determined by assuming the stoichiometry of 1:1 between DB18C6 and the metal cation. They reflected the influence of the difference in the size between the inner cavity of DB18C6 and the metal cations on the inclusion complex formation. It seems that the moment analysis method based on HPLC separation is effective for the multifaceted analysis of chemical reactions because some characteristics of the method are different from those of other conventional methods. It must contribute to the dissemination of an opportunity for the study of chemical reactions to many researchers because of the versatility of HPLC.
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Affiliation(s)
- Kanji Miyabe
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
| | - Amane Ishitobi
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
| | - Kanoko Hiyama
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
| | - Fuzuki Kubotani
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
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3
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Mazzoccanti G, Franzini R, Ciogli A, Pierini M, Buonsenso F, Faggi C, Francioso A, Manetto S, Villani C. Theoretically Predicted and Experimentally Detected Chirality of Dibenzocyclooctynes and Their Triazole Adducts with Azides. J Org Chem 2023; 88:15097-15105. [PMID: 37862264 DOI: 10.1021/acs.joc.3c01557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Dibenzocyclooctynes have emerged as promising scaffolds for bioorthogonal ligation. An important structural aspect that has not been addressed so far relates to their chirality. Herein, we explore, by theoretical and experimental methods, this structural aspect that has been neglected so far. First, computational analysis is conducted, and the results are used as a guide for the experimental investigation. Next, an array of different experiments (high-performance liquid chromatography (HPLC) on chiral columns, chiroptical spectroscopy, and X-ray diffraction) for structure elucidation is scrutinized in concert. Finally, this work demonstrates the chirality and the stereodynamic behavior of dibenzocyclooctynes and their triazole derivatives with simple azides and also uncovers their conformational behavior.
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Affiliation(s)
- Giulia Mazzoccanti
- Department of Chemistry and Technology of Drugs, Excellence 2018-2022, Sapienza University of Rome, P.le Aldo Moro 5, Rome 00185, Italy
| | - Roberta Franzini
- Department of Chemistry and Technology of Drugs, Excellence 2018-2022, Sapienza University of Rome, P.le Aldo Moro 5, Rome 00185, Italy
| | - Alessia Ciogli
- Department of Chemistry and Technology of Drugs, Excellence 2018-2022, Sapienza University of Rome, P.le Aldo Moro 5, Rome 00185, Italy
| | - Marco Pierini
- Department of Chemistry and Technology of Drugs, Excellence 2018-2022, Sapienza University of Rome, P.le Aldo Moro 5, Rome 00185, Italy
| | - Fabio Buonsenso
- Department of Chemistry and Technology of Drugs, Excellence 2018-2022, Sapienza University of Rome, P.le Aldo Moro 5, Rome 00185, Italy
| | - Cristina Faggi
- Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3-13, Sesto Fiorentino I-50019, Italy
| | - Antonio Francioso
- Department of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo 64100, Italy
| | - Simone Manetto
- Department of Chemistry and Technology of Drugs, Excellence 2018-2022, Sapienza University of Rome, P.le Aldo Moro 5, Rome 00185, Italy
| | - Claudio Villani
- Department of Chemistry and Technology of Drugs, Excellence 2018-2022, Sapienza University of Rome, P.le Aldo Moro 5, Rome 00185, Italy
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4
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Heeb JP, Clayden J, Smith MD, Armstrong RJ. Interrogating the configurational stability of atropisomers. Nat Protoc 2023; 18:2745-2771. [PMID: 37542183 DOI: 10.1038/s41596-023-00859-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 05/05/2023] [Indexed: 08/06/2023]
Abstract
Atropisomers are molecules whose stereogenicity arises from restricted rotation about a single bond. They are of current importance because of their applications in catalysis, medicine and materials science. The defining feature of atropisomeric molecules is that their stereoisomers are related to one another by bond rotation: as a result, evaluating their configurational stability (i.e., the rate at which their stereoisomers interconvert) is central to any work in this area. Important atropisomeric scaffolds include C-C linked biaryls, such as the ligand BINAP and the drug vancomycin, and C-N linked amine derivatives such as the drug telenzepine. This article focuses on the three most widely used experimental methods that are available to measure the rate of racemization in atropisomers, namely: (i) kinetic analysis of the racemization of an enantioenriched sample, (ii) dynamic HPLC and (iii) variable-temperature NMR. For each technique, an explanation of the theory is set out, followed by a detailed experimental procedure. A discussion is also included of which technique to try when confronted with a new molecular structure whose properties are not yet known. None of the three procedures require complex experimental techniques, and all can be performed by using standard analytical equipment (NMR and HPLC). The time taken to determine a racemization rate depends on which experimental method is required, but for a new compound it is generally possible to measure a racemization rate in <1 d.
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Affiliation(s)
| | | | - Martin D Smith
- Chemistry Research Laboratory, University of Oxford, Oxford, UK.
| | - Roly J Armstrong
- School of Natural and Environmental Sciences (Chemistry), Newcastle University, Newcastle Upon Tyne, UK.
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5
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Full J, Wildervanck MJ, Dillmann C, Panchal SP, Volland D, Full F, Meerholz K, Nowak-Król A. Impact of Truncation on Optoelectronic Properties of Azaborole Helicenes. Chemistry 2023:e202302808. [PMID: 37651165 DOI: 10.1002/chem.202302808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 09/01/2023]
Abstract
Herein, we report configurationally stable singly-truncated (ST) and structurally flexible doubly-truncated (DT) helically chiral compounds derived from azabora[7]helicenes by a hypothetical removal of a single or two C=C double bonds. The singly-truncated constitutional isomers were synthesized from either benzoisoquinoline (BIQ) or phenantherene building blocks and the corresponding biaryls in excellent yields to give azabora[5]helicenes with a pendant phenyl ring at a sterically hindered position. These systems highlight the electronic impact of the nitrogen donor substitution position. The compounds with a disrupted BIQ moiety (STN) possess remarkable photoluminescence quantum yields of up to 0.53 in the solid state and a blue emission in solution with dissymmetry factors of up to ca. 3×10-3 . Upon cooling to 79 K all compounds exhibit phosphorescence with lifetimes of up to ca. 0.5 s. A methyl complex of azabora[7]helicene showing excellent configurational stability was used as a chiral inducer embedded in an emissive polymer (F8BT) to produce circularly polarized organic light emitting diodes with an electroluminescence dissymmetry factor gEL of up to 0.54.
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Affiliation(s)
- Julian Full
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Martijn J Wildervanck
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Claudia Dillmann
- Department of Chemistry, University of Cologne, Greinstr. 4-6, 50939, Köln, Germany
| | - Santosh P Panchal
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Daniel Volland
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Felix Full
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Klaus Meerholz
- Department of Chemistry, University of Cologne, Greinstr. 4-6, 50939, Köln, Germany
| | - Agnieszka Nowak-Król
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Institut für Organische Chemie and Center for Nanosystems Chemistry, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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6
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Mayer LC, Heitsch S, Trapp O. Nonlinear Effects in Asymmetric Catalysis by Design: Concept, Synthesis, and Applications. Acc Chem Res 2022; 55:3345-3361. [PMID: 36351215 DOI: 10.1021/acs.accounts.2c00557] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Asymmetric synthesis constitutes a key technology for the preparation of enantiomerically pure compounds as well as for the selective control of individual stereocenters in the synthesis of complex compounds. It is thus of extraordinary importance for the synthesis of chiral drugs, dietary supplements, flavors, and fragrances, as well as novel materials with tunable and reconfigurable chiroptical properties or the assembly of complex natural products. Typically, enantiomerically pure catalysts are used for this purpose. To prepare enantiomerically pure ligands or organocatalysts, one can make use of the natural chiral pool. Ligands and organocatalysts with an atropisomeric biphenyl and binaphthyl system have become popular, as they are configurationally stable and contain a C2-symmetric skeleton, which has been found to be particularly privileged. For catalysts with opposite configurations, both product enantiomers can be obtained. Configurationally flexible biphenyl systems initially appeared to be unsuitable for this purpose, as they racemize after successful enantiomer separation and thus are neither storable nor afford a reproducible enantioselectivity. However, there are strategies that exploit the dynamics of such ligands to stereoconvergently enrich one of the catalyst enantiomers. This can be achieved, for example, by coordinating an enantiomerically pure additive to a ligand-metal complex, which results in deracemization of the configurationally flexible biphenyl system, thereby enriching the thermodynamically preferred diastereomer. In this Account, we present our strategy to design stereochemically flexible catalysts that combine the properties of supramolecular recognition, stereoconvergent alignment, and catalysis. Such systems are capable to recognize the chirality of the target product, leading to an increase in enantioselectivity during asymmetric catalysis. We have systematically developed and investigated these smart catalyst systems and have found ways to specifically design and synthesize them for various applications. In addition to (i) reaction product-induced chiral amplification, we have developed systems with (ii) intermolecular and (iii) intramolecular recognition, and successfully applied them in asymmetric catalysis. Our results pave the way for new applications such as temperature-controlled enantioselectivity, controlled inversion of enantioselectivity with the same chirality of the recognition unit, generation of positive nonlinear effects, and targeted design of autocatalytic systems through dynamic formation of transient catalysts. Understanding such systems is of enormous importance for catalytic processes leading to symmetry breaking and amplification of small imbalances of enantiomers and offer a possible explanation of homochirality of biological systems. In addition, we are learning how to target supramolecular interactions to enhance enantioselectivities in asymmetric catalysis through secondary double stereocontrol. Configurationally flexible catalysts will enable future resource-efficient development of asymmetric syntheses, as enantioselectivities can be fully switched by stereoselective alignment of the stereochemically flexible ligand core on demand.
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Affiliation(s)
- Lena C Mayer
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Simone Heitsch
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Oliver Trapp
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
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7
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Braddock DC, Duran-Corbera A, Nilforoushan M, Yang Z, He T, Santhakumar G, Bahou KA, Rzepa HS, Woscholski R, White AJP. (±)-Polysiphenol and Other Analogues via Symmetrical Intermolecular Dimerizations: A Synthetic, Spectroscopic, Structural, and Computational Study. JOURNAL OF NATURAL PRODUCTS 2022; 85:2650-2655. [PMID: 36288514 PMCID: PMC9706781 DOI: 10.1021/acs.jnatprod.2c00749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Indexed: 06/16/2023]
Abstract
We report an improved total synthesis of 4,5-dibromo-9,10-dihydrophenanthrene-2,3,6,7-tetraol, (±)-polysiphenol, via intermolecular McMurray dimerization of 5-bromovanillin and subsequent intramolecular oxidative coupling as the key steps. The synthetic route is applicable to 4,5-dichloro- and 4,5-difluoro-halologues (as well as a 4,5-dialkyl-analogue). Distinctive AA'BB' multiplets in their 1H NMR spectra for the dimethylene bridges of the dibromo and dichloro compounds reveal them to be room-temperature stable atropisomers, while for the difluoro compound they present as a singlet. X-ray crystal structure determinations of their tetramethylated synthetic precursors show atropisomeric twist angles of 48°, 46°, and 32°, respectively, with the former representing the largest yet observed in any 4,5-disubstituted-9,10-dihydrophenanthrene. DFT computational studies reveal an unprecedented two-stage atropisomeric interconversion process involving time-independent asynchronous rotations of the dimethylene bridge and the biaryl axis for halologues containing chlorine or bromine, but a more synchronous rotation for the difluoro analogue.
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8
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Ishiwari F, Takata T. Rotaxanes with dynamic mechanical chirality: Systematic studies on synthesis, enantiomer separation, racemization, and chiral-prochiral interconversion. Front Chem 2022; 10:1025977. [PMID: 36386001 PMCID: PMC9650364 DOI: 10.3389/fchem.2022.1025977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/18/2022] [Indexed: 12/02/2022] Open
Abstract
Dynamic mechanical chirality of [2]rotaxane consisting of a Cs symmetric wheel and a C2v symmetric axle is discussed via the synthesis, enantiomer separation, racemization, and chiral-prochiral interconversion. This [2]rotaxane is achiral and/or prochiral when its wheel locates at the center of the axle, but becomes chiral when the wheel moves from the center of the axle. These were proved by the experiments on the enantiomer separation and racemization. The racemization energy of the isolated single enantiomers was controlled by the bulkiness of the central substituents on the axle. Furthermore, the chiral-prochiral interconversion was achieved by relative positional control of the components. The present systematic studies will provide new insight into mechanically chiral interlocked compounds as well as the utility as dynamic chiral sources.
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Affiliation(s)
- Fumitaka Ishiwari
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Japan
- *Correspondence: Fumitaka Ishiwari, ; Toshikazu Takata,
| | - Toshikazu Takata
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Japan
- School of Materials and Chemical Technology, Tokyo Institute of Technology, Yokohama, Japan
- Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, Japan
- *Correspondence: Fumitaka Ishiwari, ; Toshikazu Takata,
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9
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Chen H, Zhu T, Sun L, Xiang L, Han H, Luo X, Chen D. Investigation of atropisomeric transformation of a novel PDE4 inhibitor with tetrahydroisoquinoline-based amide group and its primary study of binding to HSA. J Pharm Biomed Anal 2022; 221:115056. [PMID: 36150299 DOI: 10.1016/j.jpba.2022.115056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 09/10/2022] [Accepted: 09/13/2022] [Indexed: 11/29/2022]
Abstract
In this study a kinetic and thermodynamic atropisomeric transformation due to a hindered rotation around the tetrahydroisoquinoline-based amide group was investigated. Quantum chemistry calculations were applied to investigate the transformation under the gas phase and several solvents with different polarity, and then evaluated by dynamic HPLC determination. It was found that the transformation rate of constants and the half-life time varied under the influence of solvent polarity and temperature and the energies of rotational barrier were determined ranging between 87 and 92 kJ∙mol-1. A primary binding study with HSA confirmed a rapid interconversion under the simulated physiological conditions. It is therefore suggested to take this atropisomeric compound as a racemic mixture for its future drug development.
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Affiliation(s)
- Huanhuan Chen
- Laboratory of Pharmaceutical Analysis, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Rd. Zuchongzhi, Zhangjiang Hi-Tech Park, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tingfei Zhu
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Rd. Zuchongzhi, Zhangjiang Hi-Tech Park, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ling Sun
- Laboratory of Pharmaceutical Analysis, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Rd. Zuchongzhi, Zhangjiang Hi-Tech Park, Shanghai 201203, China.
| | - Lili Xiang
- Laboratory of Pharmaceutical Analysis, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Rd. Zuchongzhi, Zhangjiang Hi-Tech Park, Shanghai 201203, China.
| | - Haiyun Han
- Laboratory of Pharmaceutical Analysis, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Rd. Zuchongzhi, Zhangjiang Hi-Tech Park, Shanghai 201203, China.
| | - Xiaomin Luo
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Rd. Zuchongzhi, Zhangjiang Hi-Tech Park, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Dongying Chen
- Laboratory of Pharmaceutical Analysis, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Rd. Zuchongzhi, Zhangjiang Hi-Tech Park, Shanghai 201203, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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10
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Gong X, Li C, Cai Z, Wan X, Qian H, Yang G. Synthesis of Nitrogen-Doped Aza-Helicenes with Chiral Optical Properties. J Org Chem 2022; 87:8406-8412. [PMID: 35730543 DOI: 10.1021/acs.joc.2c00371] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aza-helicenes are one of the most important series of heterohelicenes; herein, a series of novel aza-helicenes (5H, 6H, 6S, and 8S) were prepared via Bischler-Napieralski cyclization, and the interconversion dynamic process of these aza-helicenes was revealed using density functional theory calculations. The novel nitrogen-doped [6]helicene (6H) possesses a very high interconversion energy barrier of 36.0 kcal/mol. Two enantiomers of 6H were successfully resolved by high-performance liquid chromatography and showed desired chiral optical properties. 6H with chiral optical activity and lone electrons can be a potential candidate for chiral switches, which was demonstrated using the UV and circular dichroism spectra obtained upon titration with an acid and a base.
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Affiliation(s)
- Xue Gong
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Chunmei Li
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Zhixiong Cai
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Xuejuan Wan
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Haixia Qian
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Guanghui Yang
- Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, PR China
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11
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Betzenbichler G, Huber L, Kräh S, Morkos MLK, Siegle AF, Trapp O. Chiral stationary phases and applications in gas chromatography. Chirality 2022; 34:732-759. [PMID: 35315953 DOI: 10.1002/chir.23427] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 12/15/2022]
Abstract
Chiral compounds are ubiquitous in nature and play a pivotal role in biochemical processes, in chiroptical materials and applications, and as chiral drugs. The analysis and determination of the enantiomeric ratio (er) of chiral compounds is of enormous scientific, industrial, and economic importance. Chiral separation techniques and methods have become indispensable tools to separate chiral compounds into their enantiomers on an analytical as well on a preparative level to obtain enantiopure compounds. Chiral gas chromatography and high-performance liquid chromatography have paved the way and fostered several research areas, that is, asymmetric synthesis and catalysis in organic, medicinal, pharmaceutical, and supramolecular chemistry. The development of highly enantioselective chiral stationary phases was essential. In particular, the elucidation and understanding of the underlying enantioselective supramolecular separation mechanisms led to the design of new chiral stationary phases. This review article focuses on the development of chiral stationary phases for gas chromatography. The fundamental mechanisms of the recognition and separation of enantiomers and the selectors and chiral stationary phases used in chiral gas chromatography are presented. An overview over syntheses and applications of these chiral stationary phases is presented as a practical guidance for enantioselective separation of chiral compound classes and substances by gas chromatography.
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Affiliation(s)
| | - Laura Huber
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Sabrina Kräh
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | | | - Alexander F Siegle
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Oliver Trapp
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
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12
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Chalifoux WA, Sitaula P, Malone RJ, Longhi G, Abbate S, Gualtieri E, Lucotti A, Tommasini M, Franzini R, Villani C, Catalano VJ. π‐Extended Helical Nanographenes: Synthesis and Photophysical Properties of Naphtho[1,2‐a]pyrenes. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Wesley A. Chalifoux
- University of Nevada, Reno Chemistry 1664 N. Virginia StreetDepartment of Chemistry, MS216 89557 Reno UNITED STATES
| | | | | | - Giovanna Longhi
- Università degli Studi di Brescia Dipartimento di Medicina Molecolare e Traslazionale: Universita degli Studi di Brescia Dipartimento di Medicina Molecolare e Traslazionale Dipartimento di Medicina Molecolare e Traslazionale ITALY
| | - Sergio Abbate
- Università degli Studi di Brescia Dipartimento di Medicina Molecolare e Traslazionale: Universita degli Studi di Brescia Dipartimento di Medicina Molecolare e Traslazionale Dipartimento di Medicina Molecolare e Traslazionale ITALY
| | - Eva Gualtieri
- Politecnico di Milano Dipartimento di Chimica Materiali e Ingegneria Chimica Giulio Natta Materiali e Ingegneria Chimica "G. Natta" ITALY
| | - Andrea Lucotti
- Politecnico di Milano Dipartimento di Chimica Materiali e Ingegneria Chimica Giulio Natta Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta" ITALY
| | - Matteo Tommasini
- Politecnico di Milano Dipartimento di Chimica Materiali e Ingegneria Chimica Giulio Natta Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta" ITALY
| | - Roberta Franzini
- University of Rome La Sapienza Department of Chemistry: Universita degli Studi di Roma La Sapienza Dipartimento di Chimica Dipartimento di Chimica e Tecnologie del Farmaco ITALY
| | - Claudio Villani
- University of Rome: Universita degli Studi di Roma La Sapienza Dipartimento di Chimica e Tecnologie del Farmaco ITALY
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13
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Auras S, Trapp O. Scorpio‐Ligand: Synthesis of Biphenyl‐Dihydroazepine Phosphoramidite Ligands for Asymmetric Hydrogenation. Helv Chim Acta 2021. [DOI: 10.1002/hlca.202100147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Stefanie Auras
- Department of Chemistry Ludwig Maximilian University Munich Butenandtstr. 5–13 DE-81377 Munich Germany
| | - Oliver Trapp
- Department of Chemistry Ludwig Maximilian University Munich Butenandtstr. 5–13 DE-81377 Munich Germany
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14
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Šimon P, Krupčík J, Portillo AE, Májek P, Špánik I, Armstrong DW. Headspace study of chiral interconversion of N-acetyl-homocysteine thiolactones. J Chromatogr A 2021; 1653:462381. [PMID: 34280790 DOI: 10.1016/j.chroma.2021.462381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/24/2021] [Accepted: 06/26/2021] [Indexed: 10/20/2022]
Abstract
The rate constants for (L)-N-acetyl homocysteine thiolactone enantiomerization have been obtained from batch-wise studies and by dynamic gas chromatography of racemic mixtures. Results from the batch-wise experiments show that the kinetics of racemization at 150 °C is the same for vials made of glass, silanized glass or Teflon-coated glass so that the vial surface exhibited no effect on the kinetics of racemization. From the temperature dependence of the rate constants the preexponential factor, activation energy, the activation Gibbs energy and activation entropy have been obtained from transition state theory. The catalytic effect of G-DP, G-BP and B-DP GC chiral stationary phases on racemization has been observed and quantified by the values of rate constants; B-DP exhibited the greatest activity. The Eyring activation parameters obtained from batch-wise experiment were compared with theoretical values acquired from quantum chemical modelling. Agreement between the experimental and calculated values of activation Gibbs energy, activation enthalpy and activation entropy is good. The dynamic gas chromatography of racemic mixture on chiral B-DP, G-DP and G-BP capillary columns indicate that the rate constants of forward and reverse reactions are different in chiral environments. The greatest accelerating effect in the process of enantiomerization has been identified for G-BP both in the batch-wise experiments and by the dynamic gas chromatography.
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Affiliation(s)
- Peter Šimon
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology STU, Bratislava, Slovak Republic.
| | - Ján Krupčík
- Institute of Analytical Chemistry, Faculty of Chemical and Food Technology STU, Bratislava, Slovak Republic
| | - Abiud E Portillo
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA
| | - Pavel Májek
- Institute of Analytical Chemistry, Faculty of Chemical and Food Technology STU, Bratislava, Slovak Republic
| | - Ivan Špánik
- Institute of Analytical Chemistry, Faculty of Chemical and Food Technology STU, Bratislava, Slovak Republic
| | - Daniel W Armstrong
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA
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15
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Low Temperature Dynamic Chromatography for the Separation of the Interconverting Conformational Enantiomers of the Benzodiazepines Clonazolam, Flubromazolam, Diclazepam and Flurazepam. Symmetry (Basel) 2021. [DOI: 10.3390/sym13061012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Benzodiazepines (BZDs) are an important class of psychoactive drugs with hypnotic-sedative, myorelaxant, anxiolytic and anticonvulsant properties due to interaction with the GABAa receptor in the central nervous system of mammals. BZDs are interesting both in clinical and forensic toxicology for their pharmacological characteristics and potential of abuse. The presence of a non-planar diazepine ring generates chiral conformational stereoisomers, even in the absence of stereogenic centers. A conformational enrichment of BZD at the binding sites has been reported in the literature, thus making interesting a stereodynamic screening of a wide range of BZDs. Herein, we report the investigation of three stereolabile 1,4-benzodiazepine included in the class of “designer benzodiazepines” (e.g., diclazepam, a chloro-derivative of diazepam, and two triazolo-benzodiazepines, flubromazolam and clonazolam) and a commercially available BZD known as flurazepam, in order to study the kinetic of the “ring-flip” process that allows two conformational enantiomers to interconvert at high rate at room temperature. A combination of low temperature enantioselective dynamic chromatography on chiral stationary phase and computer simulations of the experimental chromatograms allowed us to measure activation energies of enantiomerization (ΔG‡) lower than 18.5 kcal/mol. The differences between compounds have been correlated to the pattern of substitutions on the 1,4-benzodiazepinic core.
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16
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Li G, Matsuno T, Han Y, Wu S, Zou Y, Jiang Q, Isobe H, Wu J. Fused Quinoidal Dithiophene-Based Helicenes: Synthesis by Intramolecular Radical-Radical Coupling Reactions and Dynamics of Interconversion of Enantiomers. Angew Chem Int Ed Engl 2021; 60:10326-10333. [PMID: 33565194 DOI: 10.1002/anie.202100606] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/04/2021] [Indexed: 11/07/2022]
Abstract
A series of fused quinoidal dithiophene-based double and triple helicenes (1-M, 2-M, 2-M-Cl, 3-M, 3-M-Cl) were synthesized by intramolecular radical-radical coupling followed by oxidative dehydrogenation reaction. These helical molecules show dynamic interconversion of enantiomers in solution as revealed by variable-temperature NMR measurements, and the energy barriers are correlated to the substituents and topological structures. Notably, dynamic high performance liquid chromatography was used to quantitatively investigate the room-temperature racemization process between the (P,P,M)- and (P,M,M)- enantiomers of the triple helical 3-M-Cl, which gave an interconversion energy barrier in consistent with density functional theory calculations. Their optical and electrochemical properties are dependent on the fusion mode. Our studies provide both new synthetic strategy and new dynamic analytical method for helicenes with unique electronic structure.
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Affiliation(s)
- Guangwu Li
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Taisuke Matsuno
- Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yi Han
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Shaofei Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Ya Zou
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Qing Jiang
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Hiroyuki Isobe
- Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
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17
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Sabia R, Ciogli A, Pierini M, Franzini R, Iazzetti A, Villani C. Chromatographic separation of the interconverting enantiomers of imidazo- and triazole-fused benzodiazepines. J Chromatogr A 2021; 1647:462148. [PMID: 33957345 DOI: 10.1016/j.chroma.2021.462148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/25/2021] [Accepted: 04/03/2021] [Indexed: 10/21/2022]
Abstract
The toolbox of medicinal chemists includes the 1,4-benzodiazepine scaffold as a "privileged scaffold" in drug discovery. Several biologically active small molecules containing a 1,4-benzodiazepine scaffold have been approved by the FDA for the treatment of various diseases, with most of them being used for their psychotropic effects. The therapeutic potential of 1,4-benzodiazepines has stimulated the interest of synthetic chemists in developing new synthetic strategies to a range of substituted analogues for biological evaluation. A structural variation of the classical benzodiazepine skeleton is observed e.g. in alprazolam, midazolam, and related benzodiazepines, which contain a 1,2,4-triazole or an imidazole ring fused to the benzodiazepine core. Irrespective of the presence of the fused heterocyclic ring, the seven-membered diazepine ring is far from planar, and its shape resembles a twist chair. Then, the unsymmetrical substitution pattern around the seven membered cycle renders these molecules chiral, as they lack any reflection-type symmetry element. However, chirality of this molecules is labile at room temperature, becausea simple ring flipping process converts one enantiomer into the other, and 1,4-benzodiazepines exist as a mixture of rapidly interconverting conformational enantiomers in solution at or near room temperature. Physical separation of the interconverting enantiomers of diazepam and of other related 1,4-benzodiazepin-2-ones can be accomplished by low temperature HPLC on chiral stationary phases (CSPs). If the HPLC column is cooled down to temperatures where the interconversion rate is sufficiently low, compared to the chromatographic separation rate, distinct separated peaks can be observed, provided the CSP is sufficiently enantioselctive. The apparent rate constants for the on-column enantiomerization and the corresponding free energy activation barriers were obtained by simulation of exchange-deformed HPLC profiles using a computer program based on the stochastic model. Here we report on the dynamic HPLC investigations carried out on a set of fused imidazo and triazolo-benzodiazepines (alprazolam, midazolam, triazolam and estazolam) The experimental dynamic chromatograms and the corresponding interconversion barriers reported in this paper show that the third fused heterocyclic ring increase the energy barrier by 2 kcal/mol.
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Affiliation(s)
- Rocchina Sabia
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy.
| | - Alessia Ciogli
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy
| | - Marco Pierini
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy
| | - Roberta Franzini
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy
| | - Antonia Iazzetti
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy
| | - Claudio Villani
- SapienzaUniversità di Roma, Dipartimento di Chimica e Tecnologie del Farmaco, P.le A. Moro 5, 00185Rome, Italy.
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18
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Fused Quinoidal Dithiophene‐Based Helicenes: Synthesis by Intramolecular Radical–Radical Coupling Reactions and Dynamics of Interconversion of Enantiomers. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100606] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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19
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Franzini R, Pierini M, Mazzanti A, Iazzetti A, Ciogli A, Villani C. Molecular Recognition of the HPLC Whelk-O1 Selector towards the Conformational Enantiomers of Nevirapine and Oxcarbazepine. Int J Mol Sci 2020; 22:ijms22010144. [PMID: 33375681 PMCID: PMC7796420 DOI: 10.3390/ijms22010144] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/16/2020] [Accepted: 12/23/2020] [Indexed: 01/19/2023] Open
Abstract
The presence of stereogenic elements is a common feature in pharmaceutical compounds, and affording optically pure stereoisomers is a frequent issue in drug design. In this context, the study of the chiral molecular recognition mechanism fundamentally supports the understanding and optimization of chromatographic separations with chiral stationary phases. We investigated, with molecular docking, the interactions between the chiral HPLC selector Whelk-O1 and the stereoisomers of two bioactive compounds, the antiviral Nevirapine and the anticonvulsant Oxcarbazepine, both characterized by two stereolabile conformational enantiomers. The presence of fast-exchange enantiomers and the rate of the interconversion process were studied using low temperature enantioselective HPLC and VT-NMR with Whelk-O1 applied as chiral solvating agent. The values of the energetic barriers of interconversion indicate, for the single enantiomers of both compounds, half-lives sufficiently long enough to allow their separation only at critically sub-ambient temperatures. The chiral selector Whelk-O1 performed as a strongly selective discriminating agent both when applied as a chiral stationary phase (CSP) in HPLC and as CSA in NMR spectroscopy.
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Affiliation(s)
- Roberta Franzini
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
- Correspondence: (R.F.); (C.V.)
| | - Marco Pierini
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
| | - Andrea Mazzanti
- Dipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna, V. Risorgimento 4, 40136 Bologna, Italy;
| | - Antonia Iazzetti
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
| | - Alessia Ciogli
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
| | - Claudio Villani
- Department of Chemistry and Technology of Drugs, “Department of Excellence 2018−2022”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (A.I.); (A.C.)
- Correspondence: (R.F.); (C.V.)
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20
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Trapp O. Efficient Amplification in Soai's Asymmetric Autocatalysis by a Transient Stereodynamic Catalyst. Front Chem 2020; 8:615800. [PMID: 33363117 PMCID: PMC7755983 DOI: 10.3389/fchem.2020.615800] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/16/2020] [Indexed: 11/13/2022] Open
Abstract
Mechanisms leading to a molecular evolution and the formation of homochirality in nature are interconnected and a key to the underlying principles that led to the emergence of life. So far proposed mechanisms leading to a non-linear reaction behavior are based mainly on the formation of homochiral and heterochiral dimers. Since homochiral and heterochiral dimers are diastereomers of each other, the minor enantiomer is shifted out of equilibrium with the major enantiomer by dimer formation and thus a reaction or catalysis can be dominated by the remaining molecules of the major enantiomer. In this article a mechanism is shown that leads to homochirality by the formation of a highly catalytically active transient intermediate in a stereodynamically controlled reaction. This is demonstrated by Soai's asymmetric autocatalysis, in which aldehydes are transformed into the corresponding alcohols by addition of dialkylzinc reagents. The mechanism of chirogenesis proposed here shows that an apparently inefficient reaction is the best prerequisite for a selection mechanism. In addition, stereodynamic control offers the advantage that the minor diastereomeric intermediate can be interconverted into the major diastereomer and thus be stereoeconomically efficient. This is supported by computer simulation of reaction kinetics.
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Affiliation(s)
- Oliver Trapp
- Department of Chemistry, Ludwig-Maximilians-University Munich, Munich, Germany
- Max-Planck-Institute for Astronomy, Heidelberg, Germany
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21
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Trapp O, Lamour S, Maier F, Siegle AF, Zawatzky K, Straub BF. In Situ Mass Spectrometric and Kinetic Investigations of Soai's Asymmetric Autocatalysis. Chemistry 2020; 26:15871-15880. [PMID: 32822103 PMCID: PMC7756584 DOI: 10.1002/chem.202003260] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Indexed: 01/15/2023]
Abstract
Chemical reactions that lead to a spontaneous symmetry breaking or amplification of the enantiomeric excess are of fundamental interest in explaining the formation of a homochiral world. An outstanding example is Soai's asymmetric autocatalysis, in which small enantiomeric excesses of the added product alcohol are amplified in the reaction of diisopropylzinc and pyrimidine-5-carbaldehydes. The exact mechanism is still in dispute due to complex reaction equilibria and elusive intermediates. In situ high-resolution mass spectrometric measurements, detailed kinetic analyses and doping with in situ reacting reaction mixtures show the transient formation of hemiacetal complexes, which can establish an autocatalytic cycle. We propose a mechanism that explains the autocatalytic amplification involving these hemiacetal complexes. Comprehensive kinetic experiments and modelling of the hemiacetal formation and the Soai reaction allow the precise prediction of the reaction progress, the enantiomeric excess as well as the enantiomeric excess dependent time shift in the induction period. Experimental structural data give insights into the privileged properties of the pyrimidyl units and the formation of diastereomeric structures leading to an efficient amplification of even minimal enantiomeric excesses, respectively.
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Affiliation(s)
- Oliver Trapp
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstr. 5-1381377MunichGermany
- Max-Planck-Institute for AstronomyKönigstuhl 1769117HeidelbergGermany
| | - Saskia Lamour
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstr. 5-1381377MunichGermany
- Max-Planck-Institute for AstronomyKönigstuhl 1769117HeidelbergGermany
| | - Frank Maier
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstr. 5-1381377MunichGermany
| | - Alexander F. Siegle
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstr. 5-1381377MunichGermany
| | - Kerstin Zawatzky
- Department of ChemistryLudwig-Maximilians-University MunichButenandtstr. 5-1381377MunichGermany
| | - Bernd F. Straub
- Organisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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22
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Costil R, Sterling AJ, Duarte F, Clayden J. Atropisomerism in Diarylamines: Structural Requirements and Mechanisms of Conformational Interconversion. Angew Chem Int Ed Engl 2020; 59:18670-18678. [PMID: 32633101 PMCID: PMC7589358 DOI: 10.1002/anie.202007595] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Indexed: 11/30/2022]
Abstract
In common with other hindered structures containing two aromatic rings linked by a short tether, diarylamines may exhibit atropisomerism (chirality due to restricted rotation). Previous examples have principally been tertiary amines, especially those with cyclic scaffolds. Little is known of the structural requirement for atropisomerism in structurally simpler secondary and acyclic diarylamines. In this paper we describe a systematic study of a series of acyclic secondary diarylamines, and we quantify the degree of steric hindrance in the ortho positions that is required for atropisomerism to result. Through a detailed experimental and computational analysis, the role of each ortho-substituent on the mechanism and rate of conformational interconversion is rationalised. We also present a simple predictive model for the design of configurationally stable secondary diarylamines.
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Affiliation(s)
- Romain Costil
- School of ChemistryUniversity of BristolCantock's CloseBS8 1TSBristolUK
| | | | - Fernanda Duarte
- Chemistry Research LaboratoryOxford UniversityMansfield RoadOX1 3TAOxfordUK
| | - Jonathan Clayden
- School of ChemistryUniversity of BristolCantock's CloseBS8 1TSBristolUK
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23
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Atropisomerism in Diarylamines: Structural Requirements and Mechanisms of Conformational Interconversion. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007595] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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24
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Costil R, Crespi S, Pfeifer L, Feringa BL. Modulation of a Supramolecular Figure-of-Eight Strip Based on a Photoswitchable Stiff-Stilbene. Chemistry 2020; 26:7783-7787. [PMID: 32343010 PMCID: PMC7384132 DOI: 10.1002/chem.202002051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Indexed: 01/18/2023]
Abstract
The preparation, assembly and dynamic properties of photoswitchable bisphosphine ligands based on the stiff-stilbene scaffold are reported. Directional bonding and coordination-induced assembly allow complexation of these ligands with palladium(II), resulting in the formation of discrete metallo-supramolecular entities. While the Z isomer forms a simple bidentate metallo-macrocycle, an intricate double helicate figure-of-eight dimer is observed with the E ligand. Topologically 3D complexes can thus be obtained from 2D ligands. Upon irradiation with UV light, isomerization of the ligands allows control of the architecture of the formed complexes, resulting in a light-triggered modulation of the supramolecular topology. Furthermore, a mechanistic investigation unveiled the dynamic nature of the helicate chirality, where a transmission of motion from the palladium centers yields an "eight-to-eight" inversion.
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Affiliation(s)
- Romain Costil
- Stratingh Institute for ChemistryZernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
| | - Stefano Crespi
- Stratingh Institute for ChemistryZernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
| | - Lukas Pfeifer
- Stratingh Institute for ChemistryZernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
| | - Ben L. Feringa
- Stratingh Institute for ChemistryZernike Institute for Advanced MaterialsUniversity of GroningenNijenborgh 49747AGGroningenThe Netherlands
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25
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Development of A Novel High Throughput Photo-catalyst Screening Procedure: UV-A Degradation of 17α-Ethinylestradiol with Doped TiO 2-Based Photo-catalysts. MATERIALS 2020; 13:ma13061365. [PMID: 32197369 PMCID: PMC7143925 DOI: 10.3390/ma13061365] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/13/2020] [Accepted: 03/17/2020] [Indexed: 11/16/2022]
Abstract
The rising pollution of surface water by endocrine disruptive chemicals (EDCS) could lead to the persistent harm of aquatic wildlife. Addressing this concern, advanced waste water treatment techniques should be established in addition to the present sewage treatment. Therefore, the promising advanced oxidation process of photocatalysis is discussed. With the aim of establishing a novel high throughput screening approach for photocatalysts, a workflow resting upon the use of a self-constructed 60-fold parallel stirring UV-A LED photoreactor, followed by parallel sample extraction by SPE and sequential automated analysis by GC-MS, was developed, and is presented in this article. With the described system, TiO2-based photocatalysts, doped with different amounts of zinc, and synthesised by a sol-gel-route, were tested regarding their activity in the photocatalytic degradation of the synthetic estrogen 17α-ethinylestradiol. Thereby, the functional behavior of the photoreactor system and its applicability in a high throughput process could be evaluated. As a result of the catalyst screening, TiO2 catalysts with low amounts of zinc were found with a significantly higher activity, compared to undoped TiO2. In conclusion, the presented system provides an easily accessible high throughput method for a variety of photocatalytic experiments.
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26
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Fu X, Cebo M, Ikegami T, Lämmerhofer M. Separation of carbohydrate isomers and anomers on poly-N-(1H-tetrazole-5-yl)-methacrylamide-bonded stationary phase by hydrophilic interaction chromatography as well as determination of anomer interconversion energy barriers. J Chromatogr A 2020; 1620:460981. [PMID: 32115232 DOI: 10.1016/j.chroma.2020.460981] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/11/2020] [Accepted: 02/15/2020] [Indexed: 12/31/2022]
Abstract
A new commercially available HPLC column, poly-N-(1H-tetrazole-5-yl)-methacrylamide-bonded stationary phase (Daicel DCpak PTZ), was systematically evaluated for its carbohydrate isomer separation capability by hydrophilic interaction liquid chromatography (HILIC) with charged aerosol detection (CAD) or (tandem) mass spectrometry. Reducing sugars tend to split into two anomer peaks which makes carbohydrate isomer separations in non-derivatized form even more complicated. For practical purposes anomer separations are therefore ideally suppressed which can be accomplished by using high temperature or high pH that are both associated with fast interconversion kinetics leading to peak coalescence, or on the other hand by conditions with low chromatographic anomer selectivity. Four major hexoses (glucose, mannose, galactose, fructose), five main pentoses (ribose, ribulose, xylose, xylulose, arabinose) and five most important disaccharides (maltose, cellobiose, lactose, sucrose, trehalose) were analyzed as single carbohydrate standards by isocratic HILIC with 0.1% (v/v) formic acid and 2 mM ammonium acetate at various temperatures to study anomer interconversion equilibria in a pH-dependent manner. Rate constants of forward (α→β) and backward (β→α) anomerization and corresponding energy barriers were calculated. The energy barriers of anomerisation were in the range of around 83-91 kJ mol-1 at 298 K and the difference between forward (α→β) and backward reaction (β→α) was typically between 1-3 kJ mol-1. The systematic studies finally allowed to pick conditions for the simultaneous analysis of all 14 carbohydrates by HILIC-ESI-MS(/MS) with PTZ in gradient elution mode. A combination of carbohydrate isomer-selective LC (with PTZ), tandem MS (with carbohydrate group-selective MS1 and some species-specific SRM transitions) and a simple deconvolution strategy allowed the determination of all carbohydrates of the complex test mixture except for the disaccharide pair lactose and maltose (which can be determined as sum). Consequently, the proposed method represents a successful step towards a global glycometabolomics profiling method of mono- and disaccharides by HILIC-ESI-MS/MS.
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Affiliation(s)
- Xiaoqing Fu
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
| | - Malgorzata Cebo
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
| | - Tohru Ikegami
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany; Department of Materials Synthesis, Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
| | - Michael Lämmerhofer
- Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany.
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27
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Grabarics M, Lettow M, Kirk AT, von Helden G, Causon TJ, Pagel K. Plate-height model of ion mobility-mass spectrometry. Analyst 2020; 145:6313-6333. [DOI: 10.1039/d0an00433b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In analogy to chromatography, a plate-height model of drift tube ion mobility-mass spectrometry is presented that describes zone broadening and resolving power in ion mobility separations.
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Affiliation(s)
- Márkó Grabarics
- Department of Biology
- Chemistry and Pharmacy
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
| | - Maike Lettow
- Department of Biology
- Chemistry and Pharmacy
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
| | - Ansgar T. Kirk
- Institute of Electrical Engineering and Measurement Technology
- Department of Sensors and Measurement Technology
- Leibniz Universität Hannover
- 30167 Hannover
- Germany
| | - Gert von Helden
- Fritz Haber Institute of the Max Planck Society
- Department of Molecular Physics
- 14195 Berlin
- Germany
| | - Tim J. Causon
- Department of Chemistry
- Institute of Analytical Chemistry
- University of Natural Resources and Life Sciences
- Vienna
- 1190 Vienna
| | - Kevin Pagel
- Department of Biology
- Chemistry and Pharmacy
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
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28
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Multidimensional gas chromatography investigation of concentration and temperature effects of oxime interconversion on ionic liquid and poly(ethylene glycol) stationary phases. Anal Chim Acta 2019; 1081:200-208. [DOI: 10.1016/j.aca.2019.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/01/2019] [Accepted: 07/07/2019] [Indexed: 01/22/2023]
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29
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Mayorga Burrezo P, Jiménez VG, Blasi D, Ratera I, Campaña AG, Veciana J. Organic Free Radicals as Circularly Polarized Luminescence Emitters. Angew Chem Int Ed Engl 2019; 58:16282-16288. [DOI: 10.1002/anie.201909398] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Indexed: 01/06/2023]
Affiliation(s)
- Paula Mayorga Burrezo
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra E-08193 Cerdanyola Barcelona Spain
| | - Vicente G. Jiménez
- Department of Organic Chemistry University of Granada (UGR) C. U. Fuentenueva 18071 Granada Spain
| | - Davide Blasi
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra E-08193 Cerdanyola Barcelona Spain
| | - Imma Ratera
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra E-08193 Cerdanyola Barcelona Spain
| | - Araceli G. Campaña
- Department of Organic Chemistry University of Granada (UGR) C. U. Fuentenueva 18071 Granada Spain
| | - Jaume Veciana
- Department of Molecular Nanoscience and Organic Materials Institut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra E-08193 Cerdanyola Barcelona Spain
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30
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Mayorga Burrezo P, Jiménez VG, Blasi D, Ratera I, Campaña AG, Veciana J. Organic Free Radicals as Circularly Polarized Luminescence Emitters. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201909398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Paula Mayorga Burrezo
- Department of Molecular Nanoscience and Organic MaterialsInstitut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra E-08193 Cerdanyola Barcelona Spain
| | - Vicente G. Jiménez
- Department of Organic ChemistryUniversity of Granada (UGR) C. U. Fuentenueva 18071 Granada Spain
| | - Davide Blasi
- Department of Molecular Nanoscience and Organic MaterialsInstitut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra E-08193 Cerdanyola Barcelona Spain
| | - Imma Ratera
- Department of Molecular Nanoscience and Organic MaterialsInstitut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra E-08193 Cerdanyola Barcelona Spain
| | - Araceli G. Campaña
- Department of Organic ChemistryUniversity of Granada (UGR) C. U. Fuentenueva 18071 Granada Spain
| | - Jaume Veciana
- Department of Molecular Nanoscience and Organic MaterialsInstitut de Ciència de Materials de Barcelona (ICMAB)/ CIBER-BBN Campus Universitari de Bellaterra E-08193 Cerdanyola Barcelona Spain
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31
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Scholtes JF, Trapp O. Enantioselectivity Induced by Stereoselective Interlocking: A Novel Core Motif for Tropos Ligands. Chemistry 2019; 25:11707-11714. [PMID: 31336015 PMCID: PMC7522685 DOI: 10.1002/chem.201902017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Indexed: 11/09/2022]
Abstract
Well-defined supramolecular interactions are a powerful tool to control the stereochemistry of a catalytic reaction. In this paper, we report a novel core motif for fluxional 2,2'-biphenyl ligands carrying (S)-amino acid-derived interaction sites in 5,5'-position that cause spontaneous enrichment of the Rax rotamer. The process is based on strong non-covalent interlocking between interaction sites, which causes diastereoselective formation of a supramolecular ligand dimer, in which the axial chirality of the two subunits is dictated by the stereochemical information in the amino acid residues. The detailed structure of the dimer was elucidated by NMR spectroscopy and single-crystal X-ray analysis. Three different phosphorus-based ligand types, namely a bisphosphine, a bisphosphinite and a phosphoramidite were synthesized and characterized. Whereas the first one was found to exist in a strongly weighted equilibrium, the two others each exhibited stereoconvergent behavior transforming into the diastereopure Rax rotamer. Enriched ligands were used in rhodium-mediated asymmetric hydrogenation reactions of prochiral olefins in which very high enantioselectivities of up to 96:4 were achieved.
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Affiliation(s)
- Jan Felix Scholtes
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, 81377, Munich, Germany.,Max-Planck-Institute for Astronomy, Königstuhl 17, 69117, Heidelberg, Germany
| | - Oliver Trapp
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, 81377, Munich, Germany.,Max-Planck-Institute for Astronomy, Königstuhl 17, 69117, Heidelberg, Germany
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33
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Pazourek J. Determination of glucosamine and monitoring of its mutarotation by hydrophilic interaction liquid chromatography with evaporative light scattering detector. Biomed Chromatogr 2018; 32:e4368. [PMID: 30120782 DOI: 10.1002/bmc.4368] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 08/05/2018] [Accepted: 08/10/2018] [Indexed: 01/19/2023]
Abstract
Saccharides and their derivatives are typical polar analytes without a suitable UV-chromophore that are nowadays analyzed by HPLC (high-performance liquid chromatography) under HILIC (hydrophilic interaction liquid chromatography) mode. Usually an evaporative light scattering detector (ELSD) is utilized which, however, gives a nonlinear response. A procedure to overcome the problem of mutarotating (time-varying) analytes recorded with such a nonlinear response detector is described. The procedure was applied for determination of glucosamine in two commercially available pharmaceutical formulations containing the common inorganic ions that the detector gives a response to. Under optimized conditions, both the anomers of glucosamine were separated and could be determined separately. Owing to the short retention time of the analyte (a run time <4 min) and relatively slow kinetics of the anomeric conversion (equilibration time 2.5 h), mutarotation could be monitored and corresponding rate constants calculated.
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Affiliation(s)
- Jiří Pazourek
- Department of Chemical Drugs, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
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34
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Sepsey A, Németh DR, Németh G, Felinger A. Rate constant determination of interconverting enantiomers by chiral chromatography using a stochastic model. J Chromatogr A 2018; 1564:155-162. [DOI: 10.1016/j.chroma.2018.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 06/03/2018] [Accepted: 06/05/2018] [Indexed: 11/29/2022]
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35
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Albreht A, Vovk I, Mavri J, Marco-Contelles J, Ramsay RR. Evidence for a Cyanine Link Between Propargylamine Drugs and Monoamine Oxidase Clarifies the Inactivation Mechanism. Front Chem 2018; 6:169. [PMID: 29892597 PMCID: PMC5985292 DOI: 10.3389/fchem.2018.00169] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 04/27/2018] [Indexed: 01/06/2023] Open
Abstract
Successful propargylamine drugs such as deprenyl inactivate monoamine oxidase (MAO), a target in multi-faceted approaches to prevent neurodegeneration in the aging population, but the chemical structure and mechanism of the irreversible inhibition are still debated. We characterized the covalent cyanine structure linking the multi-target propargylamine inhibitor ASS234 and the flavin adenine dinucleotide in MAO-A using a combination of ultra-high performance liquid chromatography, spectroscopy, mass spectrometry, and computational methods. The partial double bond character of the cyanine chain gives rise to 4 interconverting geometric isomers of the adduct which were chromatographically separated at low temperatures. The configuration of the cyanine linker governs adduct stability with segments of much higher flexibility and rigidity than previously hypothesized. The findings indicate the importance of intramolecular electrostatic interactions in the MAO binding site and provide key information relevant to incorporation of the propargyl moiety into novel multi-target drugs. Based on the structure, we propose a mechanism of MAO inactivation applicable to all propargylamine inhibitors.
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Affiliation(s)
- Alen Albreht
- Department of Food Chemistry, National Institute of Chemistry, Ljubljana, Slovenia
| | - Irena Vovk
- Department of Food Chemistry, National Institute of Chemistry, Ljubljana, Slovenia
| | - Janez Mavri
- Laboratory of Computational Biochemistry and Drug Design, Theory Department, National Institute of Chemistry, Ljubljana, Slovenia
| | - Jose Marco-Contelles
- Laboratorio de Química Médica, Instituto de Química Orgánica General (CSIC), Madrid, Spain
| | - Rona R Ramsay
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom
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36
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Kulsing C, Nolvachai Y, Wong YF, Glouzman MI, Marriott PJ. Observation and explanation of two-dimensional interconversion of oximes with multiple heart-cutting using comprehensive multidimensional gas chromatography. J Chromatogr A 2018; 1546:97-105. [DOI: 10.1016/j.chroma.2018.02.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 02/14/2018] [Accepted: 02/19/2018] [Indexed: 11/27/2022]
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37
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Steflova J, Storch G, Wiesner S, Stockinger S, Berg R, Trapp O. Investigation of Strain-Promoted Azide–Alkyne Cycloadditions in Aqueous Solutions by Capillary Electrophoresis. J Org Chem 2018; 83:604-613. [DOI: 10.1021/acs.joc.7b02092] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Jana Steflova
- Department
Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse
5−13, 81377 München, Germany
- Department
of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, 128 40 Prague 2, Czech Republic
| | - Golo Storch
- Department
Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse
5−13, 81377 München, Germany
| | - Sarah Wiesner
- Department
Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse
5−13, 81377 München, Germany
| | - Skrollan Stockinger
- Department
Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse
5−13, 81377 München, Germany
| | - Regina Berg
- Department
Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse
5−13, 81377 München, Germany
| | - Oliver Trapp
- Department
Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse
5−13, 81377 München, Germany
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38
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Kim B, Storch G, Banerjee G, Mercado BQ, Castillo-Lora J, Brudvig GW, Mayer JM, Miller SJ. Stereodynamic Quinone-Hydroquinone Molecules That Enantiomerize at sp 3-Carbon via Redox-Interconversion. J Am Chem Soc 2017; 139:15239-15244. [PMID: 28931280 DOI: 10.1021/jacs.7b09176] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Since the discovery of molecular chirality, nonsuperimposable mirror-image organic molecules have been found to be essential across biological and chemical processes and increasingly in materials science. Generally, carbon centers containing four different substituents are configurationally stable, unless bonds to the stereogenic carbon atom are broken and re-formed. Herein, we describe sp3-stereogenic carbon-bearing molecules that dynamically isomerize, interconverting between enantiomers without cleavage of a constituent bond, nor through remote functional group migration. The stereodynamic molecules were designed to contain a pair of redox-active substituents, quinone and hydroquinone groups, which allow the enantiomerization to occur via redox-interconversion. In the presence of an enantiopure host, these molecules undergo a deracemization process that allows observation of enantiomerically enriched compounds. This work reveals a fundamentally distinct enantiomerization pathway available to chiral compounds, coupling redox-interconversion to chirality.
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Affiliation(s)
- Byoungmoo Kim
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Golo Storch
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Gourab Banerjee
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Brandon Q Mercado
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Janelle Castillo-Lora
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Gary W Brudvig
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - James M Mayer
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
| | - Scott J Miller
- Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States
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39
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Ortner F, Wiemeyer H, Mazzotti M. Interconversion and chromatographic separation of carbohydrate stereoisomers on polystyrene-divinylbenzene resins. J Chromatogr A 2017; 1517:54-65. [DOI: 10.1016/j.chroma.2017.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 07/21/2017] [Accepted: 08/04/2017] [Indexed: 11/17/2022]
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40
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Wong YF, Kulsing C, Marriott PJ. Switchable Enantioselective Three- and Four-Dimensional Dynamic Gas Chromatography–Mass Spectrometry: Example Study of On-Column Molecular Interconversion. Anal Chem 2017; 89:5620-5628. [DOI: 10.1021/acs.analchem.7b00853] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yong Foo Wong
- Australian Centre for Research
on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Chadin Kulsing
- Australian Centre for Research
on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Philip J. Marriott
- Australian Centre for Research
on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
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41
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Dai J, Wang C, Traeger SC, Discenza L, Obermeier MT, Tymiak AA, Zhang Y. The role of chromatographic and chiroptical spectroscopic techniques and methodologies in support of drug discovery for atropisomeric drug inhibitors of Bruton’s tyrosine kinase. J Chromatogr A 2017; 1487:116-128. [DOI: 10.1016/j.chroma.2017.01.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/03/2017] [Accepted: 01/05/2017] [Indexed: 01/05/2023]
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42
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Gabrieli S, Cirilli R, Benincori T, Pierini M, Rizzo S, Rossi S. BITHIENOLs: PromisingC2-Symmetric Biheteroaromatic Diols for Organic Transformation. European J Org Chem 2017. [DOI: 10.1002/ejoc.201601353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sara Gabrieli
- Dipartimento di Scienza ed Alta Tecnologia dell'Università dell'Insubria; Via Valleggio 11 22100 Como Italy
| | - Roberto Cirilli
- Dipartimento del Farmaco; Istituto Superiore di Sanità; Viale Regina Elena 299 00161 Roma Italy
| | - Tiziana Benincori
- Dipartimento di Scienza ed Alta Tecnologia dell'Università dell'Insubria; Via Valleggio 11 22100 Como Italy
| | - Marco Pierini
- Dipartimento di Chimica e Tecnologie del Farmaco; Università degli Studi di Roma “La Sapienza”; Piazzale Aldo Moro 5 00185 Roma Italy
| | | | - Sergio Rossi
- Dipartimento di Chimica; Università degli Studi di Milano; Via Golgi 19 20133 Milano Italy
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43
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Storch G, Maier F, Wessig P, Trapp O. Rotational Barriers of Substituted BIPHEP Ligands: A Comparative Experimental and Theoretical Study. European J Org Chem 2016. [DOI: 10.1002/ejoc.201600836] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Golo Storch
- Organisch-Chemisches Institut; Ruprecht-Karls Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Frank Maier
- Organisch-Chemisches Institut; Ruprecht-Karls Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Pablo Wessig
- Institut für Chemie; Universität Potsdam; Karl-Liebknecht-Str. 24-25 14476 Potsdam Germany
| | - Oliver Trapp
- Organisch-Chemisches Institut; Ruprecht-Karls Universität Heidelberg; Im Neuenheimer Feld 270 69120 Heidelberg Germany
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44
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Bouabdallah S, Ben Dhia MT, Driss MR, Touil S. Investigation of the energy barrier to the rotation of amide CN bonds in ACE inhibitors by NMR, dynamic HPLC and DFT. J Pharm Biomed Anal 2016; 128:416-425. [PMID: 27344631 DOI: 10.1016/j.jpba.2016.05.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 05/30/2016] [Accepted: 05/31/2016] [Indexed: 11/26/2022]
Abstract
The isomerizations of Enalapril, Perindopril, Enalaprilat and Lisinopril have been investigated using NMR spectroscopic, dynamic chromatographic, unified equation and DFT theoretical calculations. The thermodynamic parameters (ΔH, ΔS and ΔG) were determined by varying the temperature in the NMR experiments. At the coalescence temperature, we can evaluate the isomerization barrier to the rotation (ΔG(≠)) around the amide bond. Using dynamics chromatography and an unified equation introduced by Trap, we can determine isomerization rate constants and Gibbs activation energies. Molecular mechanics calculations also provided evidence for the presence of low energy conformers for the ACE due to restricted amide rotation. With the value of barriers (ΔE) between them of the order of (20kJmol(-1)), which is in agreement with the dynamic NMR results and DFT calculations.
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Affiliation(s)
- S Bouabdallah
- Laboratory of Heteroatom Organic Chemistry, Department of Chemistry, Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Tunisia.
| | - M T Ben Dhia
- Laboratory of Organic Chemistry: Synthèse et Etude Physico-Chimique, Faculty of Sciences of Tunis, University of El Manar, 1060 Tunis, Tunisia
| | - M R Driss
- Laboratory of Heteroatom Organic Chemistry, Department of Chemistry, Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Tunisia
| | - S Touil
- Laboratory of Heteroatom Organic Chemistry, Department of Chemistry, Faculty of Sciences of Bizerte, University of Carthage, 7021 Jarzouna, Tunisia
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45
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Substituent effects on axial chirality in 1-aryl-3,4-dihydroisoquinolines: controlling the rate of bond rotation. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.01.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Storch G, Pallmann S, Rominger F, Trapp O. Stereodynamic tetrahydrobiisoindole "NU-BIPHEP(O)"s: functionalization, rotational barriers and non-covalent interactions. Beilstein J Org Chem 2016; 12:1453-8. [PMID: 27559397 PMCID: PMC4979906 DOI: 10.3762/bjoc.12.141] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/28/2016] [Indexed: 12/02/2022] Open
Abstract
Stereodynamic ligands offer intriguing possibilities in enantioselective catalysis. “NU-BIPHEPs” are a class of stereodynamic diphosphine ligands which are easily accessible via rhodium-catalyzed double [2 + 2 + 2] cycloadditions. This study explores the preparation of differently functionalized “NU-BIPHEP(O)” compounds, the characterization of non-covalent adduct formation and the quantification of enantiomerization barriers. In order to explore the possibilities of functionalization, we studied modifications of the ligand backbone, e.g., with 3,5-dichlorobenzoyl chloride. Diastereomeric adducts with Okamoto-type cellulose derivatives and on-column deracemization were realized on the basis of non-covalent interactions. Enantioselective dynamic HPLC (DHPLC) allowed for the determination of rotational barriers of ΔG‡298K = 92.2 ± 0.3 kJ mol−1 and 99.5 ± 0.1 kJ mol−1 underlining the stereodynamic properties of “NU-BIPHEPs” and “NU-BIPHEP(O)s”, respectively. These results make the preparation of tailor-made functionalized stereodynamic ligands possible and give an outline for possible applications in enantioselective catalysis.
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Affiliation(s)
- Golo Storch
- Organisch-Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Sebastian Pallmann
- Organisch-Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
| | - Oliver Trapp
- Organisch-Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany
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47
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Pasti L, Marchetti N, Guzzinati R, Catani M, Bosi V, Dondi F, Sepsey A, Felinger A, Cavazzini A. Microscopic models of liquid chromatography: From ensemble-averaged information to resolution of fundamental viewpoint at single-molecule level. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2015.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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48
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Fischer F, Siegle AF, Checinski M, Fischer C, Kral K, Thede R, Trapp O, Hapke M. Synthesis of Naphthylpyridines from Unsymmetrical Naphthylheptadiynes and the Configurational Stability of the Biaryl Axis. J Org Chem 2016; 81:3087-102. [DOI: 10.1021/acs.joc.5b02190] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Fabian Fischer
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, D-18059 Rostock, Germany
| | - Alexander F. Siegle
- Organisch-Chemisches
Institut, Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Marek Checinski
- CreativeQuantum GmbH (Adlershof), Wegedornstrasse
32, D-12524 Berlin, Germany
| | - Christine Fischer
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, D-18059 Rostock, Germany
| | - Karolin Kral
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, D-18059 Rostock, Germany
| | - Richard Thede
- Institut für
Biochemie, Universität Greifswald, Felix-Hausdorff-Straße 4, D-17487 Greifswald, Germany
| | - Oliver Trapp
- Organisch-Chemisches
Institut, Universität Heidelberg, Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany
| | - Marko Hapke
- Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, D-18059 Rostock, Germany
- Johannes Kepler Universität Linz, Institut für
Katalyse, Altenberger Straße 69, A-4040 Linz, Austria
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Gmeiner J, Seibicke M, Behrens S, Spliethoff B, Trapp O. Investigation of the Hydrogenation of 5-Methylfurfural by Noble Metal Nanoparticles in a Microcapillary Reactor. CHEMSUSCHEM 2016; 9:583-587. [PMID: 26871887 DOI: 10.1002/cssc.201600045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Indexed: 06/05/2023]
Abstract
On-column reaction gas chromatography (ocRGC) was successfully utilized as high-throughput platform for monitoring of the conversion and selectivity of hydrogenation of 5-methylfurfural catalyzed by polymer-stabilized Ru and Pd nanoparticles. We were able to elucidate the effect of various reaction conditions, mainly together with the catalyst loading on the conversion rate and the selectivity of the reaction. Our strategy yields significant improvements in reaction analysis times and cost effectiveness in comparison to standard methods. We are able to demonstrate that ocRGC approach provides valuable information about the reaction system that gives scientists a tool to design suitable catalytic systems for enhanced sustainable chemistry in the future.
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Affiliation(s)
- Julia Gmeiner
- Organisch-Chemisches-Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Max Seibicke
- Organisch-Chemisches-Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Silke Behrens
- Institut für Katalyseforschung und Technologie, Herrmann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
| | - Bernd Spliethoff
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Oliver Trapp
- Organisch-Chemisches-Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
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