1
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Humpert S, Schneider D, Lang M, Schulze A, Neumaier F, Holschbach M, Bier D, Neumaier B. Radiosynthesis and In Vitro Evaluation of [ 11C]tozadenant as Adenosine A 2A Receptor Radioligand. Molecules 2024; 29:1089. [PMID: 38474602 DOI: 10.3390/molecules29051089] [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: 02/06/2024] [Revised: 02/23/2024] [Accepted: 02/27/2024] [Indexed: 03/14/2024] Open
Abstract
Tozadenant (4-hydroxy-N-(4-methoxy-7-morpholinobenzo[d]thiazol-2-yl)-4-methylpiperidine-1-carboxamide) is a highly selective adenosine A2A receptor (A2AR) antagonist and a promising lead structure for the development of A2AR-selective positron emission tomography (PET) probes. Although several 18F-labelled tozadenant derivatives showed favorable in vitro properties, recent in vivo PET studies observed poor brain penetration and lower specific binding than anticipated from the in vitro data. While these findings might be attributable to the structural modification associated with 18F-labelling, they could also reflect inherent properties of the parent compound. However, PET studies with radioisotopologues of tozadenant to evaluate its cerebral pharmacokinetics and brain distribution are still lacking. In the present work, we applied N-Boc-O-desmethyltozadenant as a suitable precursor for the preparation of [O-methyl-11C]tozadenant ([11C]tozadenant) by O-methylation with [11C]methyl iodide followed by acidic deprotection. This approach afforded [11C]tozadenant in radiochemical yields of 18 ± 2%, with molar activities of 50-60 GBq/µmol (1300-1600 mCi/µmol) and radiochemical purities of 95 ± 3%. In addition, in vitro autoradiography in pig and rat brain slices demonstrated the expected striatal accumulation pattern and confirmed the A2AR specificity of the radioligand, making it a promising tool for in vivo PET studies on the cerebral pharmacokinetics and brain distribution of tozadenant.
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Affiliation(s)
- Swen Humpert
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Daniela Schneider
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Markus Lang
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Annette Schulze
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Felix Neumaier
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Marcus Holschbach
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Dirk Bier
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
| | - Bernd Neumaier
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5), Wilhelm-Johnen-Str., 52428 Jülich, Germany
- Institute of Radiochemistry and Experimental Molecular Imaging, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
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2
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Tian H, Lee W, Li Y, Dweck MJ, Mendoza A, Harran PG, Houk KN. Origin of Octafluorocyclopentene Polyelectrophilicity. J Am Chem Soc 2024; 146:5375-5382. [PMID: 38354320 DOI: 10.1021/jacs.3c12690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Octafluorocyclopentene (OFCP) has found utility as a polyelectrophile in substitution cascades that form complex macrocyclic compounds. The Harran group synthesis of macrocyclic polypeptides depends on OFCP as a linker, combining with four different nucleophilic units of a polypeptide. We report a computational investigation of the origins of OFCP reactivity and a rationale for controlled mono-, di-, tri-, and tetrasubstitution of fluoride ions by heteroatomic nucleophiles. The roles of inductive, negative hyperconjugative, and resonance electron-donation by fluoride substituents are explored for the reaction of OFCP, less-fluorinated analogues, and common electrophilic alkenes with several different nucleophiles.
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Affiliation(s)
- Haowen Tian
- College of Chemistry, Nankai University, 94 Weijin Road, Tianjin 300071, China
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - William Lee
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Yuli Li
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Morris J Dweck
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Angel Mendoza
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Patrick G Harran
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
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3
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Lipka BM, Honeycutt DS, Bassett GM, Kowal TN, Adamczyk M, Cartnick ZC, Betti VM, Goldberg JM, Wang F. Ultra-rapid Electrophilic Cysteine Arylation. J Am Chem Soc 2023; 145:23427-23432. [PMID: 37857310 DOI: 10.1021/jacs.3c10334] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Rapid bond-forming reactions are crucial for efficient bioconjugation. We describe a simple and practical strategy for facilitating ultra-rapid electrophilic cysteine arylation. Using a variety of sulfone-activated pyridinium salts, this uncatalyzed reaction proceeds with exceptionally high rate constants, ranging from 9800 to 320,000 M-1·s-1, in pH 7.0 aqueous buffer at 25 °C. Such reactions allow for stoichiometric bioconjugation of micromolar cysteine within minutes or even seconds. Even though the arylation is extremely fast, the chemistry exhibits excellent selectivity, thus furnishing functionalized peptides and proteins with both high conversion and purity.
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Affiliation(s)
- Bradley M Lipka
- Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, Rhode Island 02881, United States
| | - Daniel S Honeycutt
- Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, Rhode Island 02881, United States
| | - Gregory M Bassett
- Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, Rhode Island 02881, United States
| | - Taylor N Kowal
- Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, Rhode Island 02881, United States
| | - Max Adamczyk
- Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, Rhode Island 02881, United States
| | - Zachary C Cartnick
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Vincent M Betti
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Jacob M Goldberg
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Fang Wang
- Department of Chemistry, University of Rhode Island, 140 Flagg Rd, Kingston, Rhode Island 02881, United States
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4
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Delaney CP, Lin E, Huang Q, Yu IF, Rao G, Tao L, Jed A, Fantasia SM, Püntener KA, Britt RD, Hartwig JF. Cross-coupling by a noncanonical mechanism involving the addition of aryl halide to Cu(II). Science 2023; 381:1079-1085. [PMID: 37676958 DOI: 10.1126/science.adi9226] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 08/08/2023] [Indexed: 09/09/2023]
Abstract
Copper complexes are widely used in the synthesis of fine chemicals and materials to catalyze couplings of heteroatom nucleophiles with aryl halides. We show that cross-couplings catalyzed by some of the most active catalysts occur by a mechanism not previously considered. Copper(II) [Cu(II)] complexes of oxalamide ligands catalyze Ullmann coupling to form the C-O bond in aryl ethers by concerted oxidative addition of an aryl halide to Cu(II) to form a high-valent species that is stabilized by radical character on the oxalamide ligand. This mechanism diverges from those involving Cu(I) and Cu(III) intermediates that have been posited for other Ullmann-type couplings. The stability of the Cu(II) state leads to high turnover numbers, >1000 for the coupling of phenoxide with aryl chloride electrophiles, as well as an ability to run the reactions in air.
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Affiliation(s)
- Connor P Delaney
- College of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Eva Lin
- College of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Qinan Huang
- College of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Isaac F Yu
- College of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Guodong Rao
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Lizhi Tao
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Ana Jed
- College of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Serena M Fantasia
- Pharmaceutical Division, Synthetic Molecules Technical Development, Process Chemistry and Catalysis, F. Hoffmann-La Roche, Ltd., Basel, CH-4070, Switzerland
| | - Kurt A Püntener
- Pharmaceutical Division, Synthetic Molecules Technical Development, Process Chemistry and Catalysis, F. Hoffmann-La Roche, Ltd., Basel, CH-4070, Switzerland
| | - R David Britt
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
- Miller Institute for Basic Research in Science, University of California, Berkeley, CA 94720, USA
| | - John F Hartwig
- College of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
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5
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Abstract
Cyclopropanes that carry an electron-accepting group react as electrophiles in polar, ring-opening reactions. Analogous reactions at cyclopropanes with additional C2 substituents allow one to access difunctionalized products. Consequently, functionalized cyclopropanes are frequently used building blocks in organic synthesis. The polarization of the C1-C2 bond in 1-acceptor-2-donor-substituted cyclopropanes not only favorably enhances reactivity toward nucleophiles but also directs the nucleophilic attack toward the already substituted C2 position. Monitoring the kinetics of non-catalytic ring-opening reactions with a series of thiophenolates and other strong nucleophiles, such as azide ions, in DMSO provided the inherent SN2 reactivity of electrophilic cyclopropanes. The experimentally determined second-order rate constants k 2 for cyclopropane ring-opening reactions were then compared to those of related Michael additions. Interestingly, cyclopropanes with aryl substituents at the C2 position reacted faster than their unsubstituted analogues. Variation of the electronic properties of the aryl groups at C2 gave rise to parabolic Hammett relationships.
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Affiliation(s)
- Andreas Eitzinger
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5–13, 81377München, Germany
| | - Armin R. Ofial
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5–13, 81377München, Germany
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6
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Piszel PE, Orzolek BJ, Olszewski AK, Rotella ME, Spiewak AM, Kozlowski MC, Weix DJ. Protodemetalation of (Bipyridyl)Ni(II)-Aryl Complexes Shows Evidence for Five-, Six-, and Seven-Membered Cyclic Pathways. J Am Chem Soc 2023:10.1021/jacs.3c00618. [PMID: 37026854 PMCID: PMC10558627 DOI: 10.1021/jacs.3c00618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Protonation of C-M bonds and its microscopic reverse, metalation of C-H bonds, are fundamental steps in a variety of metal-catalyzed processes. As such, studies on protonation of C-M bonds can shed light on C-H activation. We present here studies on the rate of protodemetalation (PDM) of a suite of arylnickel(II) complexes with various acids that provide evidence for a concerted, cyclic transition state for the PDM of C-Ni bonds and demonstrate that five-, six-, and seven-membered transition states are particularly favorable. Our data show that while the rate of protodemetalation of arylnickel(II) complexes scales with acidity for many acids, several are faster than predicted by pKa. For example, while acetic acid and acetohydroxamic acid are much less acidic than HCl, they both protodemetalate arylnickel(II) complexes significantly faster than HCl. Our data also show how in the case of acetohydroxamic acid, a seven-membered cyclic transition state (CH3C(O)NHOH) can be more favorable than a six-membered transition state (CH3C(O)NHOH). Similarly, five-membered transition states, such as for pyrazole, are highly favorable as well. Comparison of transition state polarization (from density functional theory) compares these new nickel transition states to better-studied precious-metal systems and demonstrates how the base can change the polarization of the transition state giving rise to opposing electronic preferences. Collectively, these studies suggest several new avenues for study in C-H activation as well as approaches to accelerate or slow protodemetalation in nickel catalysis.
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Affiliation(s)
- Paige E. Piszel
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Brandon J. Orzolek
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Alyssa K. Olszewski
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Madeline E. Rotella
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Amanda M. Spiewak
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Marisa C. Kozlowski
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Daniel J. Weix
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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7
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Kommineni N, Sainaga Jyothi VGS, Butreddy A, Raju S, Shapira T, Khan W, Angsantikul P, Domb AJ. SNAC for Enhanced Oral Bioavailability: An Updated Review. Pharm Res 2023; 40:633-650. [PMID: 36539668 DOI: 10.1007/s11095-022-03459-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022]
Abstract
The delivery of proteins and peptides via an oral route poses numerous challenges to improve the oral bioavailability and patient compliance. To overcome these challenges, as well as to improve the permeation of proteins and peptides via intestinal mucosa, several chemicals have been studied such as surfactants, fatty acids, bile salts, pH modifiers, and chelating agents, amongst these medium chain fatty acid like C10 (sodium caprate) and Sodium N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC) and its derivatives that have been well studied from a clinical perspective. This current review enumerates the challenges involved in protein and peptide delivery via the oral route, i.e., non-invasive routes of protein and peptide administration. This review also covers the chemistry behind SNAC and toxicity as well as mechanisms to enhance the oral delivery of clinically proven molecules like simaglutide and other small molecules under clinical development, as well as other permeation enhancers for efficient delivery of proteins and peptides.
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Affiliation(s)
- Nagavendra Kommineni
- Center for Biomedical Research, Population Council, New York, NY, 10065, USA.
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India.
| | - Vaskuri G S Sainaga Jyothi
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
| | - Arun Butreddy
- Department of Pharmaceutics and Drug Delivery, School of Pharmacy, The University of Mississippi, Oxford, MS, 38677, USA
| | - Saka Raju
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
| | - Tovi Shapira
- School of Pharmacy and Faculty of Medicine, The Hebrew University of Jerusalem, Hadassah Medical Center, Ein Kerem Campus, 91120, Jerusalem, Israel
| | - Wahid Khan
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, Hyderabad, Telangana, India
- Natco Research Centre, NATCO Pharma Limited, Hyderabad, 500018, India
| | - Pavimol Angsantikul
- Center for Biomedical Research, Population Council, New York, NY, 10065, USA
| | - Abraham J Domb
- School of Pharmacy and Faculty of Medicine, The Hebrew University of Jerusalem, Hadassah Medical Center, Ein Kerem Campus, 91120, Jerusalem, Israel.
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8
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Abstract
Reactivity scales are useful research tools for chemists, both experimental and computational. However, to determine the reactivity of a single molecule, multiple measurements need to be carried out, which is a time-consuming and resource-intensive task. In this Tutorial Review, we present alternative approaches for the efficient generation of quantitative structure-reactivity relationships that are based on quantum chemistry, supervised learning, and uncertainty quantification. First published in 2002, we observe a tendency for these relationships to become not only more predictive but also more interpretable over time.
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Affiliation(s)
- Maike Vahl
- Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstraße 17, 38106 Braunschweig, Germany.
| | - Jonny Proppe
- Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Gaußstraße 17, 38106 Braunschweig, Germany.
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9
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Lipka BM, Betti VM, Honeycutt DS, Zelmanovich DL, Adamczyk M, Wu R, Blume HS, Mendina CA, Goldberg JM, Wang F. Rapid Electrophilic Cysteine Arylation with Pyridinium Salts. Bioconjug Chem 2022; 33:2189-2196. [DOI: 10.1021/acs.bioconjchem.2c00419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Bradley M. Lipka
- Department of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island02881, United States
| | - Vincent M. Betti
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York13346, United States
| | - Daniel S. Honeycutt
- Department of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island02881, United States
| | - Daniel L. Zelmanovich
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York13346, United States
| | - Max Adamczyk
- Department of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island02881, United States
| | - Ruojun Wu
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York13346, United States
| | - Harrison S. Blume
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York13346, United States
| | - Caitlin A. Mendina
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York13346, United States
| | - Jacob M. Goldberg
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York13346, United States
| | - Fang Wang
- Department of Chemistry, University of Rhode Island, 140 Flagg Road, Kingston, Rhode Island02881, United States
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10
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Solvent effect, quantification and correlation analysis of the nucleophilicities of cyclic secondary amines. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02483-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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11
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Dlamini MC, Dlamini ML, Mente P, Tlhaole B, Erasmus R, Maubane-Nkadimeng MS, Moma JA. Photocatalytic abatement of phenol on amorphous TiO2-BiOBr-bentonite heterostructures under visible light irradiation. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.04.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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12
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Rojas JJ, Croft RA, Sterling AJ, Briggs EL, Antermite D, Schmitt DC, Blagojevic L, Haycock P, White AJP, Duarte F, Choi C, Mousseau JJ, Bull JA. Amino-oxetanes as amide isosteres by an alternative defluorosulfonylative coupling of sulfonyl fluorides. Nat Chem 2022; 14:160-169. [PMID: 35087220 DOI: 10.1038/s41557-021-00856-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 11/11/2021] [Indexed: 01/10/2023]
Abstract
Bioisosteres provide valuable design elements that medicinal chemists can use to adjust the structural and pharmacokinetic characteristics of bioactive compounds towards viable drug candidates. Aryl oxetane amines offer exciting potential as bioisosteres for benzamides-extremely common pharmacophores-but are rarely examined due to the lack of available synthetic methods. Here we describe a class of reactions for sulfonyl fluorides to form amino-oxetanes by an alternative pathway to the established SuFEx (sulfonyl-fluoride exchange) click reactivity. A defluorosulfonylation forms planar oxetane carbocations simply on warming. This disconnection, comparable to a typical amidation, will allow the application of vast existing amine libraries. The reaction is tolerant to a wide range of polar functionalities and is suitable for array formats. Ten oxetane analogues of bioactive benzamides and marketed drugs are prepared. Kinetic and computational studies support the formation of an oxetane carbocation as the rate-determining step, followed by a chemoselective nucleophile coupling step.
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Affiliation(s)
- Juan J Rojas
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Rosemary A Croft
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Alistair J Sterling
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Edward L Briggs
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Daniele Antermite
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Daniel C Schmitt
- Pfizer Worldwide Research, Development and Medical, Groton, CT, USA
| | - Luka Blagojevic
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Peter Haycock
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Andrew J P White
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK
| | - Fernanda Duarte
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, UK
| | - Chulho Choi
- Pfizer Worldwide Research, Development and Medical, Groton, CT, USA
| | - James J Mousseau
- Pfizer Worldwide Research, Development and Medical, Groton, CT, USA
| | - James A Bull
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, London, UK.
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13
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Taylor NP, Gonzalez JA, Nichol GS, García-Domínguez A, Leach AG, Lloyd-Jones GC. A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics. J Org Chem 2021; 87:721-729. [PMID: 34928611 DOI: 10.1021/acs.joc.1c02729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R'3-nRnX (X = P, N; R' = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
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Affiliation(s)
- Nicholas P Taylor
- EaStChem, School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Jorge A Gonzalez
- EaStChem, School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Gary S Nichol
- EaStChem, School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Andrés García-Domínguez
- EaStChem, School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
| | - Andrew G Leach
- School of Health Sciences, Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Guy C Lloyd-Jones
- EaStChem, School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ, United Kingdom
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14
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Micheletti G, Mayer RJ, Cino S, Boga C, Mazzanti A, Ofial AR, Mayr H. Quantification of the Lewis Basicities and Nucleophilicities of 1,3,5‐Tris(dialkylamino)benzenes. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Gabriele Micheletti
- Department of Industrial Chemistry ‘Toso Montanari' Alma Mater Studiorum – Università di Bologna Viale Risorgimento 4 40136 Bologna Italy
| | - Robert J. Mayer
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Germany
| | - Silvia Cino
- Department of Industrial Chemistry ‘Toso Montanari' Alma Mater Studiorum – Università di Bologna Viale Risorgimento 4 40136 Bologna Italy
| | - Carla Boga
- Department of Industrial Chemistry ‘Toso Montanari' Alma Mater Studiorum – Università di Bologna Viale Risorgimento 4 40136 Bologna Italy
| | - Andrea Mazzanti
- Department of Industrial Chemistry ‘Toso Montanari' Alma Mater Studiorum – Università di Bologna Viale Risorgimento 4 40136 Bologna Italy
| | - Armin R. Ofial
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Germany
| | - Herbert Mayr
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Germany
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15
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Matić M, Denegri B. Prediction of the kinetic stability of
N
‐alkyl‐X‐pyridinium ions in dichloromethane. J PHYS ORG CHEM 2021. [DOI: 10.1002/poc.4248] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Mirela Matić
- Faculty of Pharmacy and Biochemistry University of Zagreb Zagreb Croatia
| | - Bernard Denegri
- Faculty of Pharmacy and Biochemistry University of Zagreb Zagreb Croatia
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16
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Kooli A, Shalima T, Lopušanskaja E, Paju A, Lopp M. Selective C-alkylation of substituted naphthols under non-aqueous conditions. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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17
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Khrapova KO, Telezhkin AA, Volkov PA, Larina LI, Pavlov DV, Gusarova NK, Trofimov BA. Oxidative cross-coupling of secondary phosphine chalcogenides with amino alcohols and aminophenols: aspects of the reaction chemoselectivity. Org Biomol Chem 2021; 19:5098-5107. [PMID: 33861297 DOI: 10.1039/d1ob00287b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Secondary phosphine chalcogenides react with primary amino alcohols under mild conditions (room temperature, molar ratio of the initial reagents 1 : 1) in a CCl4/Et3N oxidizing system to chemoselectively deliver amides of chalcogenophosphinic acids with free OH groups. Under similar conditions, mono-cross-coupling between secondary phosphine chalcogenides and 1,2- or 1,3-aminophenols proceeds only with the participation of phenolic hydroxyl to give aminophenylchalcogenophosphinic O-esters. The yields of the synthesized functional amides or esters are 60-85%.
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Affiliation(s)
- Kseniya O Khrapova
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russian Federation.
| | - Anton A Telezhkin
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russian Federation.
| | - Pavel A Volkov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russian Federation.
| | - Lyudmila I Larina
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russian Federation.
| | - Dmitry V Pavlov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russian Federation.
| | - Nina K Gusarova
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russian Federation.
| | - Boris A Trofimov
- A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky St., 664033 Irkutsk, Russian Federation.
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18
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Abstract
The nucleophilic reactivities of substituted thiophenolates were determined by following the kinetics of their reactions with a series of quinone methides (reference electrophiles) in DMSO at 20 °C. The experimentally determined second-order rate constants were analyzed according to the Mayr-Patz equation log k = sN(N + E) to derive the nucleophile-specific reactivity parameters N and sN for ten thiophenolate ions.
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Affiliation(s)
- Patrick M Jüstel
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
| | - Cedric D Pignot
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
| | - Armin R Ofial
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
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19
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Weitkamp RF, Neumann B, Stammler HG, Hoge B. Non-Coordinated Phenolate Anions and Their Application in SF 6 Activation. Chemistry 2021; 27:6460-6464. [PMID: 32776547 PMCID: PMC8247349 DOI: 10.1002/chem.202003504] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/04/2020] [Indexed: 11/11/2022]
Abstract
The reaction of the strong monophosphazene base with the weakly acidic phenol leads to the formation of a phenol-phenolate anion with a moderately strong hydrogen bond. Application of the more powerful tetraphosphazene base (Schwesinger base) renders the isolation of the corresponding salt with a free phenolate anion possible. This compound represents the first species featuring the free phenolate anion [H5 C6 -O]- . The deprotonation of phenol derivatives with tetraphosphazene bases represents a great way for the clean preparation of salts featuring free phenolate anions and in addition allows the selective syntheses of hydrogen bonded phenol-phenolate salts. This work presents a phosphazenium phenolate salt with a redox potential of -0.72 V and its capability for the selective activation of the chemically inert greenhouse gas SF6 . The performed two-electron reduction of SF6 leads to phosphazenium pentafluorosulfanide ([SF5 ]- ) and fluoride salts.
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Affiliation(s)
- Robin F Weitkamp
- Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Beate Neumann
- Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Hans-Georg Stammler
- Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Berthold Hoge
- Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, 33615, Bielefeld, Germany
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20
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Phenol alkylation under phase transfer catalysis conditions: Insights on the mechanism and kinetics from computations. MOLECULAR CATALYSIS 2021. [DOI: 10.1016/j.mcat.2021.111566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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21
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Terashima K, Kawasaki-Takasuka T, Yamazaki T. Construction of fully substituted carbon centers containing a heteroatom and a CF 3 group via in situ generated p-quinone methides. Org Biomol Chem 2021; 19:1305-1314. [PMID: 33503080 DOI: 10.1039/d0ob02469d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
1,6-Conjugate additions of in situ generated δ-CF3-δ-substituted p-quinone methides have been achieved with a variety of heteronucleophiles under mild conditions, which led to facile and practical construction of fully substituted carbon centers including a heteroatom and a CF3 group. In particular, it was revealed that some amines themselves worked for efficient cleavage of the TBS protective group, and addition of a catalytic amount of an appropriate Brønsted acid was found to sometimes improve the progress of the desired process.
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Affiliation(s)
- Kyu Terashima
- Division of Applied Chemistry, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei 184-8588, Japan.
| | - Tomoko Kawasaki-Takasuka
- Division of Applied Chemistry, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei 184-8588, Japan.
| | - Takashi Yamazaki
- Division of Applied Chemistry, Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei 184-8588, Japan.
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22
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Pliego JR. The role of intermolecular forces in ionic reactions: the solvent effect, ion-pairing, aggregates and structured environment. Org Biomol Chem 2021; 19:1900-1914. [PMID: 33554992 DOI: 10.1039/d0ob02413a] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The environment enclosing an ionic species has a critical effect on its reactivity. In a more general sense, medium effects are not limited to the solvent, but involve the counter ion effect (ion pairing), formation of larger aggregates and structured environment as provided by the host in the case of host-guest complexes. In this review, a general view of the medium effect on anion-molecule reactions is presented. Nucleophilic substitution reactions of aliphatic (SN2) and aromatic (SNAr) systems, as well as elimination reactions (E2), are the focus of the discussion. In particular, nucleophilic fluorination with KF, CsF and tetraalkylammonium fluoride was used as the main model, because of the importance of this kind of reaction and the recent advances in the study of these systems. The solvent effect, ion pairing, formation of aggregates and formation of complexes with crown ethers, cryptands and calixarenes are discussed. For a deeper insight into the medium effect, many results of reliable theoretical calculations in close agreement with experiments were chosen as examples.
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Affiliation(s)
- Josefredo R Pliego
- Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, 36301-160, São João del-Rei, MG, Brazil.
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23
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Lopušanskaja E, Kooli A, Paju A, Järving I, Lopp M. Towards ortho-selective electrophilic substitution/addition to phenolates in anhydrous solvents. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.131935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Orlandi M, Escudero-Casao M, Licini G. Nucleophilicity Prediction via Multivariate Linear Regression Analysis. J Org Chem 2021; 86:3555-3564. [PMID: 33534569 PMCID: PMC7901016 DOI: 10.1021/acs.joc.0c02952] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
![]()
The concept of nucleophilicity is
at the basis of most transformations
in chemistry. Understanding and predicting the relative reactivity
of different nucleophiles is therefore of paramount importance. Mayr’s
nucleophilicity scale likely represents the most complete collection
of reactivity data, which currently includes over 1200 nucleophiles.
Several attempts have been made to theoretically predict Mayr’s
nucleophilicity parameters N based on calculation
of molecular properties, but a general model accounting for different
classes of nucleophiles could not be obtained so far. We herein show
that multivariate linear regression analysis is a suitable tool for
obtaining a simple model predicting N for virtually
any class of nucleophiles in different solvents for a set of 341 data
points. The key descriptors of the model were found to account for
the proton affinity, solvation energies, and sterics.
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Affiliation(s)
- Manuel Orlandi
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy.,CIRCC-Consorzio Interuniversitario per le Reattività Chimiche e la Catalisi, Padova Unit, via Marzolo 1, 35131 Padova, Italy
| | - Margarita Escudero-Casao
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy.,CIRCC-Consorzio Interuniversitario per le Reattività Chimiche e la Catalisi, Padova Unit, via Marzolo 1, 35131 Padova, Italy
| | - Giulia Licini
- Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy.,CIRCC-Consorzio Interuniversitario per le Reattività Chimiche e la Catalisi, Padova Unit, via Marzolo 1, 35131 Padova, Italy
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25
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McLaughlin C, Smith AD. Generation and Reactivity of C(1)-Ammonium Enolates by Using Isothiourea Catalysis. Chemistry 2021; 27:1533-1555. [PMID: 32557875 PMCID: PMC7894297 DOI: 10.1002/chem.202002059] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Indexed: 12/17/2022]
Abstract
C(1)-Ammonium enolates are powerful, catalytically generated synthetic intermediates applied in the enantioselective α-functionalisation of carboxylic acid derivatives. This minireview describes the recent developments in the generation and application of C(1)-ammonium enolates from various precursors (carboxylic acids, anhydrides, acyl imidazoles, aryl esters, α-diazoketones, alkyl halides) using isothiourea Lewis base organocatalysts. Their synthetic utility in intra- and intermolecular enantioselective C-C and C-X bond forming processes on reaction with various electrophiles will be showcased utilising two distinct catalyst turnover approaches.
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Affiliation(s)
- Calum McLaughlin
- EaStCHEMSchool of ChemistryUniversity of St AndrewsNorth HaughFifeKY16 9STScotland
| | - Andrew D. Smith
- EaStCHEMSchool of ChemistryUniversity of St AndrewsNorth HaughFifeKY16 9STScotland
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26
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Montecinos R, Aliaga ME, Pavez P, Cornejo P, Santos JG. Nucleofugality hierarchy, in the aminolysis reaction of 4-cyanophenyl 4-nitrophenyl carbonate and thionocarbonate. Experimental and theoretical study. NEW J CHEM 2021. [DOI: 10.1039/d0nj05837h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Brønsted plot of the reaction of 9 with secondary alicyclic amines. The concave upward non-linear plot is in accordance with two parallel mechanistic pathways.
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Affiliation(s)
- Rodrigo Montecinos
- Departamento de Quimica Fisica
- Facultad de Química y de Farmacia
- Pontificia Universidad Católica de Chile
- Santiago
- Chile
| | - Margarita E. Aliaga
- Departamento de Quimica Fisica
- Facultad de Química y de Farmacia
- Pontificia Universidad Católica de Chile
- Santiago
- Chile
| | - Paulina Pavez
- Departamento de Quimica Fisica
- Facultad de Química y de Farmacia
- Pontificia Universidad Católica de Chile
- Santiago
- Chile
| | - Patricio Cornejo
- Departamento de Quimica Fisica
- Facultad de Química y de Farmacia
- Pontificia Universidad Católica de Chile
- Santiago
- Chile
| | - José G. Santos
- Departamento de Quimica Fisica
- Facultad de Química y de Farmacia
- Pontificia Universidad Católica de Chile
- Santiago
- Chile
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27
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Sheehy KJ, Bateman LM, Flosbach NT, Breugst M, Byrne PA. Competition between N and O: use of diazine N-oxides as a test case for the Marcus theory rationale for ambident reactivity. Chem Sci 2020; 11:9630-9647. [PMID: 34094230 PMCID: PMC8162281 DOI: 10.1039/d0sc02834g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 07/23/2020] [Indexed: 11/21/2022] Open
Abstract
The preferred site of alkylation of diazine N-oxides by representative hard and soft alkylating agents was established conclusively using the 1H-15N HMBC NMR technique in combination with other NMR spectroscopic methods. Alkylation of pyrazine N-oxides (1 and 2) occurs preferentially on nitrogen regardless of the alkylating agent employed, while O-methylation of pyrimidine N-oxide (3) is favoured in its reaction with MeOTf. As these outcomes cannot be explained in the context of the hard/soft acid/base (HSAB) principle, we have instead turned to Marcus theory to rationalise these results. Marcus intrinsic barriers (ΔG ‡ 0) and Δr G° values were calculated at the DLPNO-CCSD(T)/def2-TZVPPD/SMD//M06-2X-D3/6-311+G(d,p)/SMD level of theory for methylation reactions of 1 and 3 by MeI and MeOTf, and used to derive Gibbs energies of activation (ΔG ‡) for the processes of N- and O-methylation, respectively. These values, as well as those derived directly from the DFT calculations, closely reproduce the observed experimental N- vs. O-alkylation selectivities for methylation reactions of 1 and 3, indicating that Marcus theory can be used in a semi-quantitative manner to understand how the activation barriers for these reactions are constructed. It was found that N-alkylation of 1 is favoured due to the dominant contribution of Δr G° to the activation barrier in this case, while O-alkylation of 3 is favoured due to the dominant contribution of the intrinsic barrier (ΔG ‡ 0) for this process. These results are of profound significance in understanding the outcomes of reactions of ambident reactants in general.
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Affiliation(s)
- Kevin J Sheehy
- School of Chemistry, Analytical and Biological Chemistry Research Facility, University College Cork College Road Cork Ireland
| | - Lorraine M Bateman
- School of Chemistry, Analytical and Biological Chemistry Research Facility, University College Cork College Road Cork Ireland
- School of Pharmacy, University College Cork College Road Ireland
- SSPC (Synthesis and Solid State Pharmaceutical Centre) Cork Ireland
| | - Niko T Flosbach
- Department für Chemie, Universität zu Köln Greinstraße 4 50939 Köln Germany
| | - Martin Breugst
- Department für Chemie, Universität zu Köln Greinstraße 4 50939 Köln Germany
| | - Peter A Byrne
- School of Chemistry, Analytical and Biological Chemistry Research Facility, University College Cork College Road Cork Ireland
- SSPC (Synthesis and Solid State Pharmaceutical Centre) Cork Ireland
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28
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Ayachi H, Raissi H, Mahdhaoui F, Boubaker T. Electrophilic reactivities of 7‐L‐4‐nitrobenzofurazans in σ‐complexation processes: Kinetic studies and structure–reactivity relationships. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hajer Ayachi
- Laboratoire C.H.P.N.R, Faculté des Sciences de MonastirUniversité de Monastir Avenue de l'Environnement Monastir 5019 Tunisia
| | - Hanen Raissi
- Laboratoire C.H.P.N.R, Faculté des Sciences de MonastirUniversité de Monastir Avenue de l'Environnement Monastir 5019 Tunisia
| | - Faouzi Mahdhaoui
- Laboratoire C.H.P.N.R, Faculté des Sciences de MonastirUniversité de Monastir Avenue de l'Environnement Monastir 5019 Tunisia
| | - Taoufik Boubaker
- Laboratoire C.H.P.N.R, Faculté des Sciences de MonastirUniversité de Monastir Avenue de l'Environnement Monastir 5019 Tunisia
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29
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Necibi F, Salah SB, Roger J, Hierso J, Boubaker T. Ambident electrophilicity of 4‐nitrobenzochalcogenadiazoles: Kinetic studies and structure‐reactivity relationships. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21391] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Feriel Necibi
- Laboratoire de Chimie Hétérocyclique, Produits Naturels et Réactivité (LR11S39)Faculté des SciencesUniversité de Monastir Monastir Tunisia
- Institut de Chimie Moléculaire (UMR‐CNRS 6302)Faculté des Sciences MirandeUniversité de Bourgogne Franche‐Comté Dijon France
| | - Saida Ben Salah
- Laboratoire de Chimie Hétérocyclique, Produits Naturels et Réactivité (LR11S39)Faculté des SciencesUniversité de Monastir Monastir Tunisia
| | - Julien Roger
- Institut de Chimie Moléculaire (UMR‐CNRS 6302)Faculté des Sciences MirandeUniversité de Bourgogne Franche‐Comté Dijon France
| | - Jean‐Cyrille Hierso
- Institut de Chimie Moléculaire (UMR‐CNRS 6302)Faculté des Sciences MirandeUniversité de Bourgogne Franche‐Comté Dijon France
| | - Taoufik Boubaker
- Laboratoire de Chimie Hétérocyclique, Produits Naturels et Réactivité (LR11S39)Faculté des SciencesUniversité de Monastir Monastir Tunisia
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30
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Mayer RJ, Ofial AR, Mayr H, Legault CY. Lewis Acidity Scale of Diaryliodonium Ions toward Oxygen, Nitrogen, and Halogen Lewis Bases. J Am Chem Soc 2020; 142:5221-5233. [PMID: 32125154 DOI: 10.1021/jacs.9b12998] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Equilibrium constants for the associations of 17 diaryliodonium salts Ar2I+X- with 11 different Lewis bases (halide ions, carboxylates, p-nitrophenolate, amines, and tris(p-anisyl)phosphine) have been investigated by titrations followed by photometric or conductometric methods as well as by isothermal titration calorimetry (ITC) in acetonitrile at 20 °C. The resulting set of equilibrium constants KI covers 6 orders of magnitude and can be expressed by the linear free-energy relationship lg KI = sI LAI + LBI, which characterizes iodonium ions by the Lewis acidity parameter LAI, as well as the iodonium-specific affinities of Lewis bases by the Lewis basicity parameter LBI and the susceptibility sI. Least squares minimization with the definition LAI = 0 for Ph2I+ and sI = 1.00 for the benzoate ion provides Lewis acidities LAI for 17 iodonium ions and Lewis basicities LBI and sI for 10 Lewis bases. The lack of a general correlation between the Lewis basicities LBI (with respect to Ar2I+) and LB (with respect to Ar2CH+) indicates that different factors control the thermodynamics of Lewis adduct formation for iodonium ions and carbenium ions. Analysis of temperature-dependent equilibrium measurements as well as ITC experiments reveal a large entropic contribution to the observed Gibbs reaction energies for the Lewis adduct formations from iodonium ions and Lewis bases originating from solvation effects. The kinetics of the benzoate transfer from the bis(4-dimethylamino)-substituted benzhydryl benzoate Ar2CH-OBz to the phenyl(perfluorophenyl)iodonium ion was found to follow a first-order rate law. The first-order rate constant kobs was not affected by the concentration of Ph(C6F5)I+ indicating that the benzoate release from Ar2CH-OBz proceeds via an unassisted SN1-type mechanism followed by interception of the released benzoate ions by Ph(C6F5)I+ ions.
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Affiliation(s)
- Robert J Mayer
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Armin R Ofial
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Herbert Mayr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany
| | - Claude Y Legault
- University of Sherbrooke, Department of Chemistry, Centre in Green Chemistry and Catalysis, 2500 boul. de l'Université, Sherbrooke, Québec J1K 2R1, Canada
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