1
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Matamoros E, Pérez EMS, Light ME, Cintas P, Martínez RF, Palacios JC. A True Reverse Anomeric Effect Does Exist After All: A Hydrogen Bonding Stereocontrolling Effect in 2-Iminoaldoses. J Org Chem 2024; 89:7877-7898. [PMID: 38752850 PMCID: PMC11165589 DOI: 10.1021/acs.joc.4c00562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Revised: 04/18/2024] [Accepted: 04/29/2024] [Indexed: 06/13/2024]
Abstract
The reverse anomeric effect is usually associated with the equatorial preference of nitrogen substituents at the anomeric center. Once postulated as another anomeric effect with explanations ranging from electrostatic interactions to delocalization effects, it is now firmly considered to be essentially steric in nature. Through an extensive research on aryl imines from 2-amino-2-deoxyaldoses, spanning nearly two decades, we realized that such substances often show an anomalous anomeric behavior that cannot easily be rationalized on the basis of purely steric grounds. The apparent preference, or stabilization, of the β-anomer takes place to an extent that not only neutralizes but also overcomes the normal anomeric effect. Calculations indicate that there is no stereoelectronic effect opposing the anomeric effect, resulting from the repulsion between electron lone pairs on the imine nitrogen and the endocyclic oxygen. Such data and compelling structural evidence unravel why the exoanomeric effect is largely inhibited. We are now confident, as witnessed by 2-iminoaldoses, that elimination of the exo-anomeric effect in the α-anomer is due to the formation of an intramolecular hydrogen bond between the anomeric hydroxyl and the iminic nitrogen, thereby accounting for a true electronic effect. In addition, discrete solvation may help justify the observed preference for the β-anomer.
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Affiliation(s)
- Esther Matamoros
- Departamento
de Química Orgánica e Inorgánica, Facultad de
Ciencias, and Instituto del Agua, Cambio Climático y Sostenibilidad
(IACYS), Universidad de Extremadura, 06006 Badajoz, Spain
- Departamento
de Química Orgánica, Universidad
de Málaga, Campus
Teatinos s/n, 29071 Málaga, Spain
- Instituto
de Investigación Biomédica de Málaga y Plataforma
en Nanomedicina − IBIMA, Plataforma Bionand, Parque Tecnológico de Andalucía, 29590 Málaga, Spain
| | - Esther M. S. Pérez
- Departamento
de Química Orgánica e Inorgánica, Facultad de
Ciencias, and Instituto del Agua, Cambio Climático y Sostenibilidad
(IACYS), Universidad de Extremadura, 06006 Badajoz, Spain
| | - Mark E. Light
- Department
of Chemistry, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton SO17 1BJ, U.K.
| | - Pedro Cintas
- Departamento
de Química Orgánica e Inorgánica, Facultad de
Ciencias, and Instituto del Agua, Cambio Climático y Sostenibilidad
(IACYS), Universidad de Extremadura, 06006 Badajoz, Spain
| | - R. Fernando Martínez
- Departamento
de Química Orgánica e Inorgánica, Facultad de
Ciencias, and Instituto del Agua, Cambio Climático y Sostenibilidad
(IACYS), Universidad de Extremadura, 06006 Badajoz, Spain
| | - Juan C. Palacios
- Departamento
de Química Orgánica e Inorgánica, Facultad de
Ciencias, and Instituto del Agua, Cambio Climático y Sostenibilidad
(IACYS), Universidad de Extremadura, 06006 Badajoz, Spain
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2
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Morgan KM, Baraban JH. Thermochemical Studies of Small Carbohydrates. J Org Chem 2024; 89:1769-1776. [PMID: 38227766 PMCID: PMC10845155 DOI: 10.1021/acs.joc.3c02465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/14/2023] [Accepted: 12/28/2023] [Indexed: 01/18/2024]
Abstract
Despite their prevalence in biomass and importance in biochemistry, there is still much to be learned about simple carbohydrates. Gas-phase calculations are reported here on two trioses and three tetroses. For aldotetroses, both the open-chain and furanose forms are considered. Enthalpies of reduction to polyols are calculated at the CBS-APNO level of theory, and comparisons to simple aldehydes and ketones are made. Heats of formation are calculated in two ways with overall good agreement. The heat of formation of glyceraldehyde obtained from modified HEAT calculations is also reported. Finally, calculated bond energies are presented, and the influence of the structure on the bond energies is discussed.
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Affiliation(s)
- Kathleen M. Morgan
- Department
of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, Louisiana 70125, United States
| | - Joshua H. Baraban
- Department
of Chemistry, Ben-Gurion University of the
Negev, Beer Sheva 841051, Israel
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3
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Gorelik DJ, Desai SP, Jdanova S, Turner JA, Taylor MS. Transformations of carbohydrate derivatives enabled by photocatalysis and visible light photochemistry. Chem Sci 2024; 15:1204-1236. [PMID: 38274059 PMCID: PMC10806712 DOI: 10.1039/d3sc05400d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 12/13/2023] [Indexed: 01/27/2024] Open
Abstract
This review article highlights the diverse ways in which recent developments in the areas of photocatalysis and visible light photochemistry are impacting synthetic carbohydrate chemistry. The major topics covered are photocatalytic glycosylations, generation of radicals at the anomeric position, transformations involving radical formation at non-anomeric positions, additions to glycals, processes initiated by photocatalytic hydrogen atom transfer from sugars, and functional group interconversions at OH and SH groups. Factors influencing stereo- and site-selectivity in these processes, along with mechanistic aspects, are discussed.
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Affiliation(s)
- Daniel J Gorelik
- Department of Chemistry, University of Toronto 80 St. George St. Toronto ON M5S 3H6 Canada
| | - Shrey P Desai
- Department of Chemistry, University of Toronto 80 St. George St. Toronto ON M5S 3H6 Canada
| | - Sofia Jdanova
- Department of Chemistry, University of Toronto 80 St. George St. Toronto ON M5S 3H6 Canada
| | - Julia A Turner
- Department of Chemistry, University of Toronto 80 St. George St. Toronto ON M5S 3H6 Canada
| | - Mark S Taylor
- Department of Chemistry, University of Toronto 80 St. George St. Toronto ON M5S 3H6 Canada
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4
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Jicsinszky L, Bucciol F, Chaji S, Cravotto G. Mechanochemical Degradation of Biopolymers. Molecules 2023; 28:8031. [PMID: 38138521 PMCID: PMC10745761 DOI: 10.3390/molecules28248031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/03/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
Mechanochemical treatment of various organic molecules is an emerging technology of green processes in biofuel, fine chemicals, or food production. Many biopolymers are involved in isolating, derivating, or modifying molecules of natural origin. Mechanochemistry provides a powerful tool to achieve these goals, but the unintentional modification of biopolymers by mechanochemical manipulation is not always obvious or even detectable. Although modeling molecular changes caused by mechanical stresses in cavitation and grinding processes is feasible in small model compounds, simulation of extrusion processes primarily relies on phenomenological approaches that allow only tool- and material-specific conclusions. The development of analytical and computational techniques allows for the inline and real-time control of parameters in various mechanochemical processes. Using artificial intelligence to analyze process parameters and product characteristics can significantly improve production optimization. We aim to review the processes and consequences of possible chemical, physicochemical, and structural changes.
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Affiliation(s)
- László Jicsinszky
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (F.B.); (S.C.)
| | | | | | - Giancarlo Cravotto
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (F.B.); (S.C.)
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5
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Kidonakis M, Villotet A, Witte MD, Beil SB, Minnaard AJ. Site-Selective Electrochemical Oxidation of Glycosides. ACS Catal 2023; 13:2335-2340. [PMID: 36846820 PMCID: PMC9942207 DOI: 10.1021/acscatal.2c06318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/21/2023] [Indexed: 02/01/2023]
Abstract
Quinuclidine-mediated electrochemical oxidation of glycopyranosides provides C3-ketosaccharides with high selectivity and good yields. The method is a versatile alternative to Pd-catalyzed or photochemical oxidation and is complementary to the 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-mediated C6-selective oxidation. Contrary to the electrochemical oxidation of methylene and methine groups, the reaction proceeds without oxygen.
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6
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Fu L, Ju Z, Yu M, Luo H, Zhang C, Zhang X, Cheng H, Zheng M, Jin L, Ge C. Cellulose Regeneration in Imidazolium-Based Ionic Liquids and Antisolvent Mixtures: A Density Functional Theory Study. ACS OMEGA 2022; 7:42170-42180. [PMID: 36440146 PMCID: PMC9685753 DOI: 10.1021/acsomega.2c04915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Cellulose can be dissolved in ionic liquids (ILs), and it can be recovered by adding antisolvent such as water or alcohol. In addition, the regenerated cellulose can be used for textiles, degradable membranes, hydrogels/aerogels, etc. However, the regenerated mechanism of cellulose remains ambiguous. In this work, density functional theory (DFT) calculation is reported for the cellulose regeneration from a cellulose/1-n-butyl-3-methylimidazolium acetate (BmimOAc)/water mixture. To investigate the microscopic effects of the antisolvents, we analyzed the structures and H-bonds of BmimOAc-nH2O and cellobiose-ILs-nH2O (n = 0-6) clusters. It can be found that when n ≥ 5 in the BmimOAc-nH2O clusters, the solvent-separated ion pairs (SIPs) play a dominant position in the system. With the increasing numbers of water molecules, the cation-anion interaction can be separated by water to reduce the effects of ILs on cellulose dissolution. Furthermore, the BmimOAc-nH2O and cellobiose-ILs (n = 0-6) clusters tend to be a more stable structure with high hydration in an aqueous solution. When the water molecules were added to the system, H-bonds can be formed among H2O, the hydroxyl of cellulose, and the oxygen of OAc. Therefore, the interactions between cellulose and ILs will be decreased to promote cellulose regeneration. This work would provide some help to understand the mechanism of cellulose regeneration from the view of theoretical calculation.
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Affiliation(s)
- Lanlan Fu
- College
of Chemical & Material Engineering, Quzhou University, Quzhou 324000, China
| | - Zhaoyang Ju
- College
of Chemical & Material Engineering, Quzhou University, Quzhou 324000, China
| | - Mengting Yu
- College
of Chemical & Material Engineering, Quzhou University, Quzhou 324000, China
| | | | | | - Ximing Zhang
- College
of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China
| | - Haixiang Cheng
- College
of Chemical & Material Engineering, Quzhou University, Quzhou 324000, China
| | - Minjia Zheng
- College
of Chemical & Material Engineering, Quzhou University, Quzhou 324000, China
| | - Lu Jin
- College
of Chemical & Material Engineering, Quzhou University, Quzhou 324000, China
| | - Chengsheng Ge
- College
of Chemical & Material Engineering, Quzhou University, Quzhou 324000, China
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7
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Theofanous A, Sarli I, Fragou F, Bletsa E, Deligiannakis Y, Louloudi M. Antioxidant Hydrogen-Atom-Transfer to DPPH Radicals by Hybrids of {Hyaluronic-Acid Components}@SiO 2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:12333-12345. [PMID: 36165696 DOI: 10.1021/acs.langmuir.2c02021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Hydrogen-atom-transfer (HAT) is among the key mechanisms of antioxidant and antiradical activity in natural systems. Hyaluronic acid (HyA) is currently used extensively in health and cosmetics applications. Herein it is shown that {HyA@SiO2} hybrids based on hyaluronic acid (HyA) components grafted on SiO2 nanoparticles enable significant HAT activity versus DPPH radicals, while the homogeneous HyA counterparts are practically inactive. The {HyA@SiO2} hybrids consist of the two building blocks of HyA [d-glucuronic acid (GLA) and N-acetyl-d-glucosamine (GLAM)] covalently grafted on SiO2 nanoparticles. Based on the kinetic-thermodynamic Arrhenius study, we show that the {SiO2@GLA} hybrids operate spontaneously via hydrogen-atom-transfer (HAT) with a low activation energy barrier, i.e., by ΔΕα ∼ 20 kJ/mol vs the nongrafted counterparts. Moreover, a doubly grafted {GLA@SiO2@GLAM} nanohybrid, i.e. that contains both components of HyA, shows the most significant antioxidant activity. FTIR and Raman analysis reveal that local H-bonding between the SiO2 matrix, GLA, and GLAM in {GLA@SiO2@GLAM} decreases the activation barrier of the HAT mechanism. Thus, {GLA@SiO2@GLAM} nanohybrids exemplify a novel family of materials that are not the mere sum of their components. The present case is the first example of non-phenolic molecules being able to perform antiradical HAT, opening new perspectives not foreseen until today.
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Affiliation(s)
- Annita Theofanous
- Laboratory of Biomimetic Catalysis & Hybrid Materials, Department of Chemistry, University of Ioannina, GR-45110 Panepistimioupoli Ioannina, Greece
| | - Irene Sarli
- Laboratory of Biomimetic Catalysis & Hybrid Materials, Department of Chemistry, University of Ioannina, GR-45110 Panepistimioupoli Ioannina, Greece
| | - Fotini Fragou
- Laboratory of Biomimetic Catalysis & Hybrid Materials, Department of Chemistry, University of Ioannina, GR-45110 Panepistimioupoli Ioannina, Greece
| | - Eleni Bletsa
- Laboratory of Physical Chemistry of Materials & Environment, Department of Physics, University of Ioannina, GR-45110 Panepistimioupoli Ioannina, Greece
| | - Yiannis Deligiannakis
- Laboratory of Physical Chemistry of Materials & Environment, Department of Physics, University of Ioannina, GR-45110 Panepistimioupoli Ioannina, Greece
| | - Maria Louloudi
- Laboratory of Biomimetic Catalysis & Hybrid Materials, Department of Chemistry, University of Ioannina, GR-45110 Panepistimioupoli Ioannina, Greece
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8
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Witte MD, Minnaard AJ. Site-Selective Modification of (Oligo)Saccharides. ACS Catal 2022; 12:12195-12205. [PMID: 36249871 PMCID: PMC9552177 DOI: 10.1021/acscatal.2c03876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/14/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Martin D. Witte
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Adriaan J. Minnaard
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
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