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Křížková A, Bastien G, Rončević I, Císařová I, Rybáček J, Kašička V, Kaleta J. Chlorinated Cubane-1,4-dicarboxylic Acids. J Org Chem 2024; 89:11100-11108. [PMID: 36724049 PMCID: PMC11334191 DOI: 10.1021/acs.joc.2c02872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Indexed: 02/02/2023]
Abstract
Herein, we report radical chlorination of cubane-1,4-dicarboxylic acid leading preferentially to one monochlorinated cubane dicarboxylate (ca. 70%) that is accompanied by four dichlorinated derivatives (ca. 20% in total). The exact positions of the chlorine atoms have been confirmed by X-ray diffraction of the corresponding single crystals. The acidity constants of all dicarboxylic acids in water were determined by capillary electrophoresis (3.17 ± 0.04 and 4.09 ± 0.05 for monochlorinated and ca. 2.71 ± 0.05 and 3.75 ± 0.05 for dichlorinated cubanes). All chlorinated derivatives as well as the parent diacid showed high thermal stability (decomposition above 250 °C) as documented by differential scanning calorimetry. The probable reaction pathways leading to individual isomers were proposed, and the energies of individual transition states and intermediates were obtained using density functional theory calculations (B3LYP-D3BJ/6-311+G(d,p)). The relative strain energies for all newly prepared derivatives as well as for hypothetical hexahalogenated (fluorinated, chlorinated, brominated, and iodinated) derivatives of cubane-1,4-dicarboxylic acids were predicted using wavefunction theory methods. The hexafluorinated derivative was identified as the most strained compound (57.5 kcal/mol), and the relative strain decreased as the size of halogen atoms increased (23.7 for hexachloro, 16.7 for hexabromo, and 4.0 kcal/mol for the hexaiodo derivative).
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Affiliation(s)
- Adéla Křížková
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Guillaume Bastien
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Igor Rončević
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Ivana Císařová
- Department
of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 128
40 Prague 2, Czech Republic
| | - Jiří Rybáček
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Václav Kašička
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
| | - Jiří Kaleta
- Institute
of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 160 00 Prague 6, Czech Republic
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2
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Pattison G. Assessing the rigidity of cubanes and bicyclo(1.1.1)pentanes as benzene bioisosteres. Bioorg Med Chem 2024; 102:117652. [PMID: 38442523 DOI: 10.1016/j.bmc.2024.117652] [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: 12/06/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 03/07/2024]
Abstract
Aromatic rings are critical core substructures in the majority of pharmaceutical compounds. There is much recent interest in replacing aromatic structures with saturated bioisosteres of benzene, which are generally fused or bridged ring systems. These bioisosteres often show improved solubility properties compared to benzene, and may also undergo fewer unwanted metabolic processes. One key reason why aromatic rings have proven so successful in drug design is their rigidity. This paper uses molecular dynamics simulations supported by crystallographic data to assess the rigidity of bicyclopentane and cubane ring systems as two of the most common benzene bioisosteres and compares this to benzene. Whilst a benzene ring is shown to be more flexible than these two bioisosteres in terms of its dihedral ring flexibility, substituents around the ring tend to behave in a much more similar way in both benzene and the bioisosteric systems.
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Affiliation(s)
- Graham Pattison
- School of Chemistry, University of Lincoln, Joseph Banks Laboratories, Green Lane, Lincoln, UK LN6 7DL.
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3
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Fahrenhorst-Jones T, Marshall DL, Burns JM, Pierens GK, Van Meurs DP, Kong D, Bernhardt PV, Blanksby SJ, Savage GP, Eaton PE, Williams CM. 9-Azahomocubane. Chemistry 2024; 30:e202303133. [PMID: 37823679 DOI: 10.1002/chem.202303133] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/13/2023]
Abstract
Homocubane, a highly strained cage hydrocarbon, contains two very different positions for the introduction of a nitrogen atom into the skeleton, e. g., a position 1 exchange results in a tertiary amine whereas position 9 yields a secondary amine. Herein reported is the synthesis of 9-azahomocubane along with associated structural characterization, physical property analysis and chemical reactivity. Not only is 9-azahomocubane readily synthesized, and found to be stable as predicted, the basicity of the secondary amine was observed to be significantly lower than the structurally related azabicyclo[2.2.1]heptane, although similar to 1-azahomocubane.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - David L Marshall
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Queensland, Australia
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Gregory K Pierens
- Centre for Advanced imaging, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Derek P Van Meurs
- Department of Chemistry, University of Chicago, Chicago, Illinois, 60637, USA
| | - Dehui Kong
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
| | - Stephen J Blanksby
- Central Analytical Research Facility and School of Chemistry and Physics, Queensland University of Technology, Brisbane, 4000, Queensland, Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria, Australia
| | - Philip E Eaton
- Department of Chemistry, University of Chicago, Chicago, Illinois, 60637, USA
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Queensland, Australia
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4
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Donnier-Valentin L, Kassamba S, Legros J, Fressigné C, Vuluga D, Brown RCD, Linclau B, De Paolis M. Photoinduced Formation of Cubyl Aryl Thioethers and Synthesis of Monocubyl Analogue of Dapsone. Org Lett 2023. [PMID: 37991751 DOI: 10.1021/acs.orglett.3c03372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
1,4-Disubstituted cubyl aryl thioethers were generated from the corresponding iodocubanes and aryl thiolates upon UV irradiation in dimethyl sulfoxide at room temperature. This simple procedure was found to be compatible with a variety of substituted aryl thiolates. This finding paved the way to a synthesis of the monocubyl analogue of dapsone, a key molecule in the treatment of leprosy, also known as Hansen's disease, and of acne.
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Affiliation(s)
| | - Seydou Kassamba
- Normandie Univ, UNIROUEN, COBRA, INSA Rouen, CNRS, 76000 Rouen, France
| | - Julien Legros
- Normandie Univ, UNIROUEN, COBRA, INSA Rouen, CNRS, 76000 Rouen, France
| | | | - Daniela Vuluga
- INSA Rouen, PBS, UMR 6270, CNRS, 76801 Saint-Etienne-du-Rouvray, France
| | - Richard C D Brown
- Department of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Bruno Linclau
- Department of Organic and Molecular Chemistry, Ghent University, Krijgslaan 281-S4, 9000 Ghent, Belgium
| | - Michaël De Paolis
- Normandie Univ, UNIROUEN, COBRA, INSA Rouen, CNRS, 76000 Rouen, France
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5
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Bartonek A, Klapötke TM, Krumm B. Sensitive 1,4-Disubstituted Nitro-Containing Cubanes: Structures and Properties. J Org Chem 2023; 88:12884-12890. [PMID: 37616479 DOI: 10.1021/acs.joc.3c00384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
The cubane cage system is characteristic and well known for its high strain energy, qualifying it as a promising precursor for energetic materials. 1,4-Disubstituted cubanes are the easiest accessible derivatives. A further developed laboratory-scale procedure for cubane-1,4-dicarboxylic acid dimethyl ester is presented. From this central precursor, the bis-trinitroethyl and bis-nitromethyl esters as well as the bis-methylcarbamate and bis-methylnitrocarbamate were synthesized and characterized by multinuclear NMR spectroscopy and X-ray crystallography. In addition, their physical and energetic properties were determined and studied.
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Affiliation(s)
- Andreas Bartonek
- Department of Chemistry, Ludwig-Maximilian University of Munich, Butenandtstr. 5-13(D), D-81377 Munich, Germany
| | - Thomas M Klapötke
- Department of Chemistry, Ludwig-Maximilian University of Munich, Butenandtstr. 5-13(D), D-81377 Munich, Germany
| | - Burkhard Krumm
- Department of Chemistry, Ludwig-Maximilian University of Munich, Butenandtstr. 5-13(D), D-81377 Munich, Germany
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6
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Fahrenhorst-Jones T, Kong D, Burns JM, Pierens GK, Bernhardt PV, Savage GP, Williams CM. seco-1-Azacubane-2-carboxylic acid-Amide Bond Comparison to Proline. J Org Chem 2023; 88:12867-12871. [PMID: 37647582 DOI: 10.1021/acs.joc.3c01264] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
seco-1-Azacubane-2-carboxylic acid, an unusual and sterically constrained amino acid, was found to undergo amide bond formation at both the N- and C-termini using proline based bioactive molecule templates as a concept platform.
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Affiliation(s)
- Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Dehui Kong
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Gregory K Pierens
- Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, Victoria 3168, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia
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7
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Prentice C, Martin AE, Morrison J, Smith AD, Zysman-Colman E. Benzophenone as a cheap and effective photosensitizer for the photocatalytic synthesis of dimethyl cubane-1,4-dicarboxylate. Org Biomol Chem 2023; 21:3307-3310. [PMID: 36815384 DOI: 10.1039/d3ob00231d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The key intramolecular [2 + 2] photochemical cycloaddition step in the synthesis of dimethyl cubane-1,4-dicarboxylate is performed with substoichiometric amounts of the photosensitizer benzophenone. The reaction proceeds via a Dexter energy transfer process between the triplet excited state benzophenone and a well-known cubane precursor diene. The use of the cheap and widely available benzophenone as the photosensitizer enables lower energy light to be used than the traditional photochemical process.
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Affiliation(s)
- Callum Prentice
- Organic Semiconductor Centre, EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK. .,EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, Fife, Scotland, KY16 9ST, UK.
| | - Alice E Martin
- Organic Semiconductor Centre, EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK.
| | - James Morrison
- Pharmaceutical Sciences, IMED Biotech Unit, Astra Zeneca, Macclesfield, SK10 2NA, UK
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews, North Haugh, Fife, Scotland, KY16 9ST, UK.
| | - Eli Zysman-Colman
- Organic Semiconductor Centre, EaStCHEM, School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST, UK.
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8
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Buglioni L, Raymenants F, Slattery A, Zondag SDA, Noël T. Technological Innovations in Photochemistry for Organic Synthesis: Flow Chemistry, High-Throughput Experimentation, Scale-up, and Photoelectrochemistry. Chem Rev 2022; 122:2752-2906. [PMID: 34375082 PMCID: PMC8796205 DOI: 10.1021/acs.chemrev.1c00332] [Citation(s) in RCA: 228] [Impact Index Per Article: 114.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Indexed: 02/08/2023]
Abstract
Photoinduced chemical transformations have received in recent years a tremendous amount of attention, providing a plethora of opportunities to synthetic organic chemists. However, performing a photochemical transformation can be quite a challenge because of various issues related to the delivery of photons. These challenges have barred the widespread adoption of photochemical steps in the chemical industry. However, in the past decade, several technological innovations have led to more reproducible, selective, and scalable photoinduced reactions. Herein, we provide a comprehensive overview of these exciting technological advances, including flow chemistry, high-throughput experimentation, reactor design and scale-up, and the combination of photo- and electro-chemistry.
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Affiliation(s)
- Laura Buglioni
- Micro
Flow Chemistry and Synthetic Methodology, Department of Chemical Engineering
and Chemistry, Eindhoven University of Technology, Het Kranenveld, Bldg 14—Helix, 5600 MB, Eindhoven, The Netherlands
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Fabian Raymenants
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Aidan Slattery
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Stefan D. A. Zondag
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Timothy Noël
- Flow
Chemistry Group, van ’t Hoff Institute for Molecular Sciences
(HIMS), Universiteit van Amsterdam (UvA), Science Park 904, 1098 XH, Amsterdam, The Netherlands
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9
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Brown RCD. The Longer Route can be Better: Electrosynthesis in Extended Path Flow Cells. CHEM REC 2021; 21:2472-2487. [PMID: 34302434 DOI: 10.1002/tcr.202100163] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/02/2021] [Indexed: 01/01/2023]
Abstract
This personal account provides an overview of work conducted in my research group, and through collaborations with other chemists and engineers, to develop flow electrolysis cells and apply these cells in organic electrosynthesis. First, a brief summary of my training and background in organic synthesis is provided, leading in to the start of flow electrosynthesis in my lab in collaboration with Derek Pletcher. Our work on the development of extended path electrolysis flow reactors is described from a synthetic organic chemist's perspective, including laboratory scale-up to give several moles of an anodic methoxylation product in one day. The importance of cell design is emphasised with regards to achieving good performance in laboratory electrosynthesis with productivities from hundreds of mg h-1 to many g h-1 , at high conversion in a selective fashion. A simple design of recycle flow cell that can be readily constructed in a small University workshop is also discussed, including simple modifications to improve cell performance. Some examples of flow electrosyntheses are provided, including Shono-type oxidation, anodic cleavage of protecting groups, Hofer-Moest reaction of cubane carboxylic acids, oxidative esterification and amidation of aldehydes, and reduction of aryl halides.
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Affiliation(s)
- Richard C D Brown
- School of Chemistry, The University of Southampton, Highfield, Southampton, SO17 1BJ, UK
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10
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Collin DE, Kovacic K, Light ME, Linclau B. Synthesis of Ortho-Functionalized 1,4-Cubanedicarboxylate Derivatives through Photochemical Chlorocarbonylation. Org Lett 2021; 23:5164-5169. [PMID: 34133174 DOI: 10.1021/acs.orglett.1c01702] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The cubane ring has received intense attention as a 3D benzene isostere and scaffold. Mono- and 1,4-disubstituted cubanes are well-described. Here we report a practical procedure for a direct radical-mediated chlorocarbonylation process initially reported by Bashir-Hashemi, to access a range of 2-substituted 1,4-cubanedicarboxylic ester derivatives. A subsequent regioselective ester hydrolysis to give fully differentiated 1,2,4-trisubstituted cubanes is demonstrated.
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Affiliation(s)
- Diego E Collin
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Kristina Kovacic
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Mark E Light
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Bruno Linclau
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
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