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Nazarski RB. On the Use of Deuterated Organic Solvents without TMS to Report 1H/ 13C NMR Spectral Data of Organic Compounds: Current State of the Method, Its Pitfalls and Benefits, and Related Issues. Molecules 2023; 28:4369. [PMID: 37298845 PMCID: PMC10254718 DOI: 10.3390/molecules28114369] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
The quite popular, simple but imperfect method of referencing NMR spectra to residual 1H and 13C signals of TMS-free deuterated organic solvents (referred to as Method A) is critically discussed for six commonly used NMR solvents with respect to their δH and δC values that exist in the literature. Taking into account the most reliable data, it was possible to recommend 'best' δX values for such secondary internal standards. The position of these reference points on the δ scale strongly depends on the concentration and type of analyte under study and the solvent medium used. For some solvents, chemically induced shifts (CISs) of residual 1H lines were considered, also taking into account the formation of 1:1 molecular complexes (for CDCl3). Typical potential errors that can occur as a result of improper application of Method A are considered in detail. An overview of all found δX values adopted by users of this method revealed a discrepancy of up to 1.9 ppm in δC reported for CDCl3, most likely caused by the CIS mentioned above. The drawbacks of Method A are discussed in relation to the classical use of an internal standard (Method B), two 'instrumental' schemes in which Method A is often implicitly applied, that is, the default Method C using 2H lock frequencies and Method D based on Ξ values, recommended by the IUPAC but only occasionally used for 1H/13C spectra, and external referencing (Method E). Analysis of current needs and opportunities for NMR spectrometers led to the conclusion that, for the most accurate application of Method A, it is necessary to (a) use dilute solutions in a single NMR solvent and (b) to report δX data applied for the reference 1H/13C signals to the nearest 0.001/0.01 ppm to ensure the precise characterization of new synthesized or isolated organic systems, especially those with complex or unexpected structures. However, the use of TMS in Method B is strongly recommended in all such cases.
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Affiliation(s)
- Ryszard B Nazarski
- Theoretical and Structural Chemistry Group, Department of Physical Chemistry, Faculty of Chemistry, University of Lodz, 163/165 Pomorska, 90-236 Łódź, Poland
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2
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Glycosylated and Succinylated Macrocyclic Lactones with Amyloid-β-Aggregation-Regulating Activity from a Marine Bacillus sp. Mar Drugs 2023; 21:md21020067. [PMID: 36827108 PMCID: PMC9962899 DOI: 10.3390/md21020067] [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: 11/29/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 01/22/2023] Open
Abstract
Two new glycosylated and succinylated macrocyclic lactones, succinyl glyco-oxydifficidin (1) and succinyl macrolactin O (2), were isolated from a Bacillus strain collected from an intertidal mudflat on Anmyeon Island in Korea. The planar structures of 1 and 2 were proposed using mass spectrometric analysis and NMR spectroscopic data. The absolute configurations of 1 and 2 were determined by optical rotation, J-based configuration analysis, chemical derivatizations, including the modified Mosher's method, and quantum-mechanics-based calculation. Biological evaluation of 1 and 2 revealed that succinyl glyco-oxydifficidin (1) inhibited/dissociated amyloid β (Aβ) aggregation, whereas succinyl macrolactin O (2) inhibited Aβ aggregation, indicating their therapeutic potential for disassembling and removing Aβ aggregation.
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Okude R, Mori G, Yagi A, Itami K. Programmable synthesis of multiply arylated cubanes through C-H metalation and arylation. Chem Sci 2020; 11:7672-7675. [PMID: 34094145 PMCID: PMC8159448 DOI: 10.1039/d0sc01909g] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cubane (C8H8), a cubic alkane, has long attracted attention owing to its unique 3D structure. In order to utilize the cubane scaffold widely in science and technology, a powerful method for synthesizing diverse cubane derivatives is required. Herein, we report the synthesis of mono-, di-, tri-, and tetra-arylated cubanes. Directed ortho-metalation with lithium base/alkyl zinc and subsequent palladium-catalyzed arylation enabled C–H metalation and arylation of cubane. This reaction allows the late-stage and regioselective installation of a wide range of aryl groups, realizing the first programmable synthesis of diverse multiply arylated cubanes. Cubane has attracted attention due to its unique 3D structure. Herein, we report the programmable synthesis of multiply arylated cubanes. The developed reaction allows the late-stage and regioselective installation of aryl groups.![]()
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Affiliation(s)
- Ryo Okude
- Graduate School of Science, Nagoya University Chikusa Nagoya 464-8602 Japan
| | - Genki Mori
- Central Pharmaceutical Research Institute, Japan Tobacco Inc. 1-1 Murasaki-cho, Takatsuki Osaka 569-1125 Japan
| | - Akiko Yagi
- Graduate School of Science, Nagoya University Chikusa Nagoya 464-8602 Japan
| | - Kenichiro Itami
- Graduate School of Science, Nagoya University Chikusa Nagoya 464-8602 Japan .,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University Chikusa Nagoya 464-8602 Japan
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4
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Houston SD, Fahrenhorst-Jones T, Xing H, Chalmers BA, Sykes ML, Stok JE, Farfan Soto C, Burns JM, Bernhardt PV, De Voss JJ, Boyle GM, Smith MT, Tsanaktsidis J, Savage GP, Avery VM, Williams CM. The cubane paradigm in bioactive molecule discovery: further scope, limitations and the cyclooctatetraene complement. Org Biomol Chem 2020; 17:6790-6798. [PMID: 31241113 DOI: 10.1039/c9ob01238a] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The cubane phenyl ring bioisostere paradigm was further explored in an extensive study covering a wide range of pharmaceutical and agrochemical templates, which included antibiotics (cefaclor, penicillin G) and antihistamine (diphenhydramine), a smooth muscle relaxant (alverine), an anaesthetic (ketamine), an agrochemical instecticide (triflumuron), an antiparasitic (benznidazole) and an anticancer agent (tamibarotene). This investigation highlights the scope and limitations of incorporating cubane into bioactive molecule discovery, both in terms of synthetic compatibility and physical property matching. Cubane maintained bioisosterism in the case of the Chagas disease antiparasitic benznidazole, although it was less active in the case of the anticancer agent (tamibarotenne). Application of the cyclooctatetraene (COT) (bio)motif complement was found to optimize benznidazole relative to the benzene parent, and augmented anticancer activity relative to the cubane analogue in the case of tamibarotene. Like all bioisosteres, scaffolds and biomotifs, however, there are limitations (e.g. synthetic implementation), and these have been specifically highlighted herein using failed examples. A summary of all templates prepared to date by our group that were biologically evaluated strongly supports the concept that cubane is a valuable tool in bioactive molecule discovery and COT is a viable complement.
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Affiliation(s)
- Sevan D Houston
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Tyler Fahrenhorst-Jones
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Hui Xing
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Benjamin A Chalmers
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Melissa L Sykes
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia
| | - Jeanette E Stok
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Clementina Farfan Soto
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Jed M Burns
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Paul V Bernhardt
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - James J De Voss
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
| | - Glen M Boyle
- QIMR Berghofer Medical Research Institute, PO Royal Brisbane Hospital, Brisbane, 4029, QLD, Australia
| | - Maree T Smith
- School of Biomedical Sciences, Faculty of Medicine, UQ, Brisbane, Australia
| | - John Tsanaktsidis
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC), Australia
| | - G Paul Savage
- CSIRO Manufacturing, Ian Wark Laboratory, Melbourne, 3168, Victoria (VIC), Australia
| | - Vicky M Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland (UQ), Brisbane, 4072, Queensland (QLD), Australia.
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5
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Dallaston MA, Brusnahan JS, Wall C, Williams CM. Thermal and Sensitiveness Determination of Cubanes: Towards Cubane-Based Fuels for Infrared Countermeasures. Chemistry 2019; 25:8344-8352. [PMID: 31124182 DOI: 10.1002/chem.201901086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/17/2019] [Indexed: 11/06/2022]
Abstract
As infrared seeking technology evolves, threats are better able to distinguish defensive infrared (IR) flares from true targets. Spectrally matched flares, which generally employ carbon-based fuels, are better able to decoy some advanced missiles by more closely mimicking the IR emission of the target. Cubane is a high-energy carbon-based scaffold which may be suitable for use as a fuel in spectrally matched flares. The enthalpy of formation and strain energy of a series of cubanes was predicted in silico, and their thermal and impact stability examined. All were found to undergo highly exothermic decomposition in sealed cell differential scanning calorimetry, and two cubanes subsequently underwent quantitative sensitiveness testing. Despite their F of I values being in the secondary explosive range, cubane-1,4-dicarboxylic acid (F of I=70) and 4-carbamoylcubane-1-carboxylic acid (F of I=90) were identified as potentially useful fuels for pyrotechnic infrared countermeasure flare formulations.
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Affiliation(s)
- Madeleine A Dallaston
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
| | - Jason S Brusnahan
- Defence Science and Technology Group, Edinburgh, South Australia, 5111, Australia
| | - Craig Wall
- Defence Science and Technology Group, Edinburgh, South Australia, 5111, Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, 4072, Australia
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Houston SD, Xing H, Bernhardt PV, Vanden Berg TJ, Tsanaktsidis J, Savage GP, Williams CM. Cyclooctatetraenes through Valence Isomerization of Cubanes: Scope and Limitations. Chemistry 2019; 25:2735-2739. [DOI: 10.1002/chem.201805124] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Sevan D. Houston
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Queensland Australia
| | - Hui Xing
- 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
| | - Timothy J. Vanden Berg
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Queensland Australia
| | - John Tsanaktsidis
- CSIRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria Australia
| | - G. Paul Savage
- CSIRO Manufacturing Ian Wark Laboratory Melbourne 3168 Victoria Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Queensland Australia
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7
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Abstract
Cubane is a highly strained saturated hydrocarbon system that has historically been of interest in theoretical organic chemistry. More recently it has become a molecule of interest for biological applications due to its inherent stability and limited toxicity. Of greater significance is the ability to potentially functionalize cubane at each of its carbon atoms, providing complex biologically active molecules with unique spatial arrangements for probing active sites. These characteristics have led to an increased use of cubane in pharmaceutically relevant molecules. In this Perspective we describe synthetic methodology for accessing a range of functionalized cubanes and their applications in pharmaceuticals. We also provide some perspectives on challenges and future directions in the advancement of this field.
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Affiliation(s)
- Tristan A Reekie
- School of Chemistry , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Craig M Williams
- School of Chemistry and Molecular Biosciences , University of Queensland , Brisbane , QLD 4072 , Australia
| | - Louis M Rendina
- School of Chemistry , The University of Sydney , Sydney , NSW 2006 , Australia
| | - Michael Kassiou
- School of Chemistry , The University of Sydney , Sydney , NSW 2006 , Australia
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8
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Toriyama F, Cornella J, Wimmer L, Chen TG, Dixon DD, Creech G, Baran PS. Redox-Active Esters in Fe-Catalyzed C-C Coupling. J Am Chem Soc 2016; 138:11132-5. [PMID: 27548696 PMCID: PMC5016806 DOI: 10.1021/jacs.6b07172] [Citation(s) in RCA: 211] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
Cross-couplings
of alkyl halides and organometallic species based
on single electron transfer using Ni and Fe catalyst systems have
been studied extensively, and separately, for decades. Here we demonstrate
the first couplings of redox-active esters (both isolated and derived in situ from carboxylic acids) with organozinc and organomagnesium
species using an Fe-based catalyst system originally developed for
alkyl halides. This work is placed in context by showing a direct
comparison with a Ni catalyst for >40 examples spanning a range
of
primary, secondary, and tertiary substrates. This new C–C coupling
is scalable and sustainable, and it exhibits a number of clear advantages
in several cases over its Ni-based counterpart.
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Affiliation(s)
- Fumihiko Toriyama
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Josep Cornella
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Laurin Wimmer
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Tie-Gen Chen
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Darryl D Dixon
- Chemical Development, Bristol-Myers Squibb , One Squibb Drive, New Brunswick, New Jersey 08903, United States
| | - Gardner Creech
- Chemical Development, Bristol-Myers Squibb , One Squibb Drive, New Brunswick, New Jersey 08903, United States
| | - Phil S Baran
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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9
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Biegasiewicz KF, Griffiths JR, Savage GP, Tsanaktsidis J, Priefer R. Cubane: 50 years later. Chem Rev 2015; 115:6719-45. [PMID: 26102302 DOI: 10.1021/cr500523x] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Kyle F Biegasiewicz
- †Department of Chemistry, University of Rochester, Rochester, New York 14627-0216, United States
| | - Justin R Griffiths
- ‡Department of Chemistry, University at Buffalo, Buffalo, New York 14260-1660, United States
| | - G Paul Savage
- §Ian Wark Laboratory, CSIRO Manufacturing Flagship, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - John Tsanaktsidis
- §Ian Wark Laboratory, CSIRO Manufacturing Flagship, Bayview Avenue, Clayton, Victoria 3168, Australia
| | - Ronny Priefer
- ∥College of Pharmacy, Western New England University, Springfield, Massachusetts 01119, United States
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Heaphy PJ, Griffiths JR, Dietz CJ, Paul Savage G, Priefer R. Cage opening and rearrangement of 1-iodocubane-4-carboxaldehyde. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.09.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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