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Clay WK, Buck AK, He Y, Hernández Sánchez DN, Ward NA, Lear JM, Nguyen KQ, Clark BH, Sapia RJ, Lalisse RF, Sriraman A, Cadieux CL, McElroy CA, Callam CS, Hadad CM. Treatment of Organophosphorus Poisoning with 6-Alkoxypyridin-3-ol Quinone Methide Precursors: Resurrection of Methylphosphonate-Aged Acetylcholinesterase. Chem Res Toxicol 2024; 37:643-657. [PMID: 38556765 DOI: 10.1021/acs.chemrestox.4c00024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Organophosphorus (OP) nerve agents inhibit acetylcholinesterase (AChE), creating a cholinergic crisis in which death can occur. The phosphylated serine residue spontaneously dealkylates to the OP-aged form, which current therapeutics cannot reverse. Soman's aging half-life is 4.2 min, so immediate recovery (resurrection) of OP-aged AChE is needed. In 2018, we showed pyridin-3-ol-based quinone methide precursors (QMPs) can resurrect OP-aged electric eel AChE in vitro, achieving 2% resurrection after 24 h of incubation (pH 7, 4 mM). We prepared 50 unique 6-alkoxypyridin-3-ol QMPs with 10 alkoxy groups and five amine leaving groups to improve AChE resurrection. These compounds are predicted in silico to cross the blood-brain barrier and treat AChE in the central nervous system. This library resurrected 7.9% activity of OP-aged recombinant human AChE after 24 h at 250 μM, a 4-fold increase from our 2018 report. The best QMP (1b), with a 6-methoxypyridin-3-ol core and a diethylamine leaving group, recovered 20.8% (1 mM), 34% (4 mM), and 42.5% (predicted maximum) of methylphosphonate-aged AChE activity over 24 h. Seven QMPs recovered activity from AChE aged with Soman and a VX degradation product (EA-2192). We hypothesize that QMPs form the quinone methide (QM) to realkylate the phosphylated serine residue as the first step of resurrection. We calculated thermodynamic energetics for QM formation, but there was no trend with the experimental biochemical data. Molecular docking studies revealed that QMP binding to OP-aged AChE is not the determining factor for the observed biochemical trends; thus, QM formation may be enzyme-mediated.
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Affiliation(s)
- William K Clay
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Anne K Buck
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yiran He
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Dalyanne N Hernández Sánchez
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Nathan A Ward
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Jeremy M Lear
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Kenny Q Nguyen
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Benjamin H Clark
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Ryan J Sapia
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Remy F Lalisse
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Aishwarya Sriraman
- Oak Ridge Institute for Science and Education, 1299 Bethel Valley Road, Oak Ridge, Tennessee 37830, United States
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - C Linn Cadieux
- U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, Maryland 21010, United States
| | - Craig A McElroy
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Christopher S Callam
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
| | - Christopher M Hadad
- Department of Chemistry and Biochemistry, College of Arts and Sciences, The Ohio State University, Columbus, Ohio 43210, United States
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Abstract
A polarity-reversing radical cascade strategy for alkene di-functionalization by vicinal C-C and C-P bond-formation has been developed. This approach to concurrently adding phosphorous and a heteroarene across an olefin is enabled by photocatalytic generation of electrophilic P-centered radicals. Upon chemoselective addition to an olefin, the resulting nucleophilic C-centered radical selectively combines with electrophilic heteroarenes, such as pyridines. This multi-component coupling scheme for phosphinylalkylation complements classic two-component methods for hydrophosphinylation of alkenes and C-H phosphinylation of arenes. Included competition and photo-quenching experiments provide insight into the selectivity and mechanism of this polarity-reversal pathway.
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Affiliation(s)
- J Quentin Buquoi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
| | - Jeremy M Lear
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
| | - Xin Gu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
| | - David A Nagib
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, United States
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Lear JM, Buquoi JQ, Gu X, Pan K, Mustafa DN, Nagib DA. Multi-component heteroarene couplings via polarity-reversed radical cascades. Chem Commun (Camb) 2019; 55:8820-8823. [PMID: 31134975 DOI: 10.1039/c9cc03498f] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A multi-component radical addition strategy enables difunctionalization of alkenes with heteroarenes and a variety of radical precursors, including N3, P(O)R2, and CF3. This unified approach for coupling diverse classes of electrophilic radicals and heteroarenes to vinyl ethers allows for direct, vicinal C-C as well as C-N, C-P, and C-Rf bond formation.
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Affiliation(s)
- Jeremy M Lear
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
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Wang L, Lear JM, Rafferty SM, Fosu SC, Nagib DA. Ketyl radical reactivity via atom transfer catalysis. Science 2018; 362:225-229. [PMID: 30309953 DOI: 10.1126/science.aau1777] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/13/2018] [Indexed: 11/02/2022]
Abstract
Single-electron reduction of a carbonyl to a ketyl enables access to a polarity-reversed platform of reactivity for this cornerstone functional group. However, the synthetic utility of the ketyl radical is hindered by the strong reductants necessary for its generation, which also limit its reactivity to net reductive mechanisms. We report a strategy for net redox-neutral generation and reaction of ketyl radicals. The in situ conversion of aldehydes to α-acetoxy iodides lowers their reduction potential by more than 1 volt, allowing for milder access to the corresponding ketyl radicals and an oxidative termination event. Upon subjecting these iodides to a dimanganese decacarbonyl precatalyst and visible light irradiation, an atom transfer radical addition (ATRA) mechanism affords a broad scope of vinyl iodide products with high Z-selectivity.
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Affiliation(s)
- Lu Wang
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Jeremy M Lear
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Sean M Rafferty
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Stacy C Fosu
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - David A Nagib
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA.
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