1
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Twum K, Nadimi S, Osei FB, Puttreddy R, Ojong YB, Hayward JJ, Rissanen K, Trant JF, Beyeh NK. The "Nitrogen Effect": Complexation with Macrocycles Potentiates Fused Heterocycles to Form Halogen Bonds in Competitive Solvents. Chem Asian J 2023; 18:e202201308. [PMID: 36705487 DOI: 10.1002/asia.202201308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 01/28/2023]
Abstract
Weak intermolecular forces are typically very difficult to observe in highly competitive polar protic solvents as they are overwhelmed by the quantity of competing solvent. This is even more challenging for three-component ternary assemblies of pure organic compounds. In this work, we overcome these complications by leveraging the binding of fused aromatic N-heterocycles in an open resorcinarene cavity to template the formation of a three-component halogen-bonded ternary assembly in a protic polar solvent system.
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Affiliation(s)
- Kwaku Twum
- Department of Chemistry, Oakland University, 146 Library Drive, Rochester, Michigan, 48309, USA
| | - Sanaz Nadimi
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Canada
| | - Frank Boateng Osei
- Department of Chemistry, Oakland University, 146 Library Drive, Rochester, Michigan, 48309, USA
| | - Rakesh Puttreddy
- Department of Chemistry, University of Jyvaskyla, Survontie 9 B, FI-40014, Jyvaskyla, Finland
| | - Yvonne Bessem Ojong
- Department of Chemistry, Oakland University, 146 Library Drive, Rochester, Michigan, 48309, USA
| | - John J Hayward
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Canada
| | - Kari Rissanen
- Department of Chemistry, University of Jyvaskyla, Survontie 9 B, FI-40014, Jyvaskyla, Finland
| | - John F Trant
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, Ontario, N9B 3P4, Canada
| | - Ngong Kodiah Beyeh
- Department of Chemistry, Oakland University, 146 Library Drive, Rochester, Michigan, 48309, USA
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2
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Banerjee A, Hayward JJ, Trant JF. "Breaking bud": the effect of direct chemical modifications of phytocannabinoids on their bioavailability, physiological effects, and therapeutic potential. Org Biomol Chem 2023; 21:3715-3732. [PMID: 36825573 DOI: 10.1039/d3ob00068k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the two "major cannabinoids". However, their incorporation into clinical and nutraceutical preparations is challenging, owing to their limited bioavailability, low water solubility, and variable pharmacokinetic profiles. Understanding the organic chemistry of the major cannabinoids provides us with potential avenues to overcome these issues through derivatization. The resulting labile pro-drugs offer ready cannabinoid release in vivo, have augmented bioavailability, or demonstrate interesting pharmacological properties in their own right. This review identifies and discusses a subset of these advanced derivatization strategies for the major cannabinoids, where the starting material is the pure phytocannabinoid itself, and the final product either a cannabinoid pro-drug, or a novel pharmacoactive material.
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Affiliation(s)
- Abhinandan Banerjee
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Ave., Windsor, ON N9B 3P4, Canada.
| | - John J Hayward
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Ave., Windsor, ON N9B 3P4, Canada.
| | - John F Trant
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Ave., Windsor, ON N9B 3P4, Canada.
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3
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Hayward JJ, Trant JF, Mader L. Giving Preparative Thin-Layer Chromatography Some Tender Loving Care. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/a-1766-2416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractPreparative thin-layer chromatography (prepTLC) is a commonly used method of purification suitable for small-scale reactions. However, descriptions of the preferred methodology to load, run, and recover samples from prepTLC are non-standard and varied, making it part of the ‘hidden curriculum’ of laboratory techniques. In this article we report on the simple, cost-effective methods we use to load and collect samples from a plate, which enhance the convenience, speed, and precision of this technique.
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4
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Watanabe LK, Ahmed ZS, Hayward JJ, Heyer E, Macdonald CLB, Rawson JM. Oxidative addition of 1,2,5,6-Tetrathiocins to Co(I): A Re-Examination of Crown Ether Functionalized Benzene Dithiolate Cobalt(III) Complexes. Organometallics 2022. [DOI: 10.1021/acs.organomet.1c00559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lara K. Watanabe
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, N9B 3P4 Ontario, Canada
| | - Zeinab S. Ahmed
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, N9B 3P4 Ontario, Canada
| | - John J. Hayward
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, N9B 3P4 Ontario, Canada
| | - Elodie Heyer
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, N9B 3P4 Ontario, Canada
| | - Charles L. B. Macdonald
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, N9B 3P4 Ontario, Canada
- Department of Chemistry and Biochemistry, Carleton University, Ottawa, K1S 5B6 Ontario, Canada
| | - Jeremy M. Rawson
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, N9B 3P4 Ontario, Canada
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5
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Mader L, Hayward JJ, Porter LA, Trant JF. A revised synthesis of 6-alkoxy-2-aminopurines with late-stage convergence allowing for increased molecular complexity. NEW J CHEM 2022. [DOI: 10.1039/d2nj02204d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This streamlined synthesis allows the alcohol at the 6-position of 6-alkoxy-2-arylaminopurines to be used only in moderate excess, rather than as solvent, opening up the possibility of accessing more complicated molecules.
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Affiliation(s)
- Lavleen Mader
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - John J. Hayward
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - Lisa A. Porter
- Department of Biomedical Sciences, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - John F. Trant
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
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6
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Seddon JM, Fortes M, Kelly-Smith M, Sommerlad SF, Hayward JJ, Burmeister L, De Risio L, Mellersh C, Freeman J, Strain GM. Deafness in Australian Cattle Dogs associated to QTL on chromosome 20 in genome-wide association study analyses. Anim Genet 2021; 52:694-702. [PMID: 34318504 DOI: 10.1111/age.13115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2021] [Indexed: 11/29/2022]
Abstract
Pigment-associated deafness is a common hereditary condition in a range of dog breeds. The aim of this study was to perform a genome-wide association analysis to investigate the genetic architecture of deafness in Australian Cattle Dogs. Genotypes for 104 757 polymorphisms in 216 dogs were available for analyses after quality control. A genomic relationship matrix was used in the mixed model analyses to account for polygenic effects, as we tested each polymorphism for its association with deafness, in a case/control experimental design. Three approaches were used to code the genotypes and test for additive, recessive and dominant SNP effects. The genome-wide association study analyses identified a clear association peak on CFA20, with the most significant SNPs on this chromosome (1.29 × 10-4 ) in the vicinity of MITF. Variants in MITF have been associated with white pigmentation in dogs and with deafness in humans and other species, supporting the premise that canine deafness is associated with variants in or near this gene. A recessive inheritance for the peak in CFA20 is possible given the significant results in the recessive model; however, the estimated heritability was low (4.54 × 10-5 ). Further validation, identification of variants and testing in other dog breeds are needed.
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Affiliation(s)
- J M Seddon
- School of Veterinary Science, The University of Queensland, Gatton, Qld, 4343, Australia
| | - M Fortes
- School of Chemistry and Molecular Biosciences, Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Brisbane, Qld, 4072, Australia
| | - M Kelly-Smith
- Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, LA, 70803, USA
| | - S F Sommerlad
- School of Veterinary Science, The University of Queensland, Gatton, Qld, 4343, Australia
| | - J J Hayward
- Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA
| | - L Burmeister
- Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK
| | - L De Risio
- Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK
| | - C Mellersh
- Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK
| | - J Freeman
- Animal Health Trust, Newmarket, Suffolk, CB8 7UU, UK
| | - G M Strain
- Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, LA, 70803, USA
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7
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Watanabe LK, Wrixon JD, Ahmed ZS, Hayward JJ, Abbasi P, Pilkington M, Macdonald CLB, Rawson JM. Oxidative addition of tetrathiocins to palladium(0) and platinum(0): a route to dithiolate coordination complexes. Dalton Trans 2020; 49:9086-9093. [PMID: 32572417 DOI: 10.1039/d0dt01678k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The preparation of a series of 4,4',5,5'-substituted benzo-fused 1,2,5,6-tetrathiocins X2C6H2S4C6H2X2 (1a-1g) were prepared from the reaction of S2Cl2 with 1,2-C6H4X2 (X = OMe, OEt; X2 = OCH2O, OCH2CH2O, OCH2CH2CH2O, MeNC([double bond, length as m-dash]O)NMe, O(CH2CH2O)4). The oxidative addition of 1a-1g to zero-valent Pd2dba3 or Pt2dba3 (dba = dibenzylideneacetone) in the presence of bis (diphenylphosphino)ethane (dppe) resulted in formation of the substituted mononuclear benzenedithiolate complexes M(L)(dppe) [L = dithiolate ligand; 2a-2g (M = Pd) and 3a-3g (M = Pt)] in 37-89% yield based on recrystallized material. Representative examples of M(L)(dppf) [dppf = bis-diphenylphosphinoferrocene; 4a, 4g (M = Pd) and 5g (M = Pt)] were prepared in a similar fashion. The structures of all derivatives were determined by X-ray diffraction, multinuclear NMR and elemental analysis. The reactivity of the two crown ether dithiolate complexes, 2g and 4g, with 1 equivalent of NaBPh4 led to isolation of the 1 : 1 complexes in which the Na+ cation is bound in the macrocyclic crown, [Na(2g)(MeOH)2][BPh4] and [Na(4g)][BPh4] whose structures were determined by X-ray diffraction. Electrochemical studies supported through DFT calculations on the crown ether derivatives revealed a series of ligand-based oxidation waves corresponding to the dithiolate ligand (and dppf for 4g and 5g) whose redox potentials were shifted by ca. +0.1 V on binding to Na+.
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Affiliation(s)
- Lara K Watanabe
- Department of Chemistry and Biochemistry, the University of Windsor, 401 Sunset Avenue, Windsor, ON, Canada N9B 3P4.
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8
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Nikoo S, Meister PJ, Hayward JJ, Gauld JW. An Assessment of Computational Methods for Calculating Accurate Structures and Energies of Bio-Relevant Polysulfur/Selenium-Containing Compounds. Molecules 2018; 23:molecules23123323. [PMID: 30558190 PMCID: PMC6320821 DOI: 10.3390/molecules23123323] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 12/12/2018] [Accepted: 12/12/2018] [Indexed: 12/02/2022] Open
Abstract
The heavier chalcogens sulfur and selenium are important in organic and inorganic chemistry, and the role of such chalcogens in biological systems has recently gained more attention. Sulfur and, to a lesser extent selenium, are involved in diverse reactions from redox signaling to antioxidant activity and are considered essential nutrients. We investigated the ability of the DFT functionals (B3LYP, B3PW91, ωB97XD, M06-2X, and M08-HX) relative to electron correlation methods MP2 and QCISD to produce reliable and accurate structures as well as thermochemical data for sulfur/selenium-containing systems. Bond lengths, proton affinities (PA), gas phase basicities (GPB), chalcogen–chalcogen bond dissociation enthalpies (BDE), and the hydrogen affinities (HA) of thiyl/selenyl radicals were evaluated for a range of small polysulfur/selenium compounds and cysteine per/polysulfide. The S–S bond length was found to be the most sensitive to basis set choice, while the geometry of selenium-containing compounds was less sensitive to basis set. In mixed chalcogens species of sulfur and selenium, the location of the sulfur atom affects the S–Se bond length as it can hold more negative charge. PA, GPB, BDE, and HA of selenium systems were all lower, indicating more acidity and more stability of radicals. Extending the sulfur chain in cysteine results in a decrease of BDE and HA, but these plateau at a certain point (199 kJ mol−1 and 295 kJ mol−1), and PA and GPB are also decreased relative to the thiol, indicating that the polysulfur species exist as thiolates in a biological system. In general, it was found that ωB97XD/6-311G(2d,p) gave the most reasonable structures and thermochemistry relative to benchmark calculations. However, nuances in performance are observed and discussed.
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Affiliation(s)
- Sahar Nikoo
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada.
| | - Paul J Meister
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada.
| | - John J Hayward
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada.
| | - James W Gauld
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4, Canada.
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9
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Aboelnga MM, Hayward JJ, Gauld JW. Unraveling the Critical Role Played by Ado762'OH in the Post-Transfer Editing by Archaeal Threonyl-tRNA Synthetase. J Phys Chem B 2018; 122:1092-1101. [PMID: 29281289 DOI: 10.1021/acs.jpcb.7b10254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Archaeal threonyl-tRNA synthetase (ThrRS) possesses an editing active site wherein tRNAThr that has been misaminoacylated with serine (i.e., Ser-tRNAThr) is hydrolytically cleaved to serine and tRNAThr. It has been suggested that the free ribose sugar hydroxyl of Ado76 of the tRNAThr (Ado762'OH) is the mechanistic base, promoting hydrolysis by orienting a nucleophilic water near the scissile Ser-tRNAThr ester bond. We have performed a computational study, involving molecular dynamics (MD) and hybrid ONIOM quantum mechanics/molecular mechanics (QM/MM) methods, considering all possible editing mechanisms to gain an understanding of the role played by Ado762'OH group. More specifically, a range of concerted or stepwise mechanisms involving four-, six-, or eight-membered transition structures (total of seven mechanisms) were considered. In addition, these seven mechanisms were fully optimized using three different DFT functionals, namely, B3LYP, M06-2X, and M06-HF. The M06-HF functional gave the most feasible energy barriers followed by the M06-2X functional. The most favorable mechanism proceeds stepwise through two six-membered ring transition states in which the Ado762'OH group participates, overall, as a shuttle for the proton transfer from the nucleophilic H2O to the bridging oxygen (Ado763'O) of the substrate. More specifically, in the first step, which has a barrier of 25.9 kcal/mol, the Ado762'-OH group accepts a proton from the attacking nucleophilic water while concomitantly transferring its proton onto the substrates C-Ocarb center. Then, in the second step, which also proceeds with a barrier of 25.9 kcal/mol, the Ado762'-OH group transfers its proton on the adjacent Ado763'-oxygen, cleaving the scissile Ccarb-O3'Ado76 bond, while concomitantly accepting a proton from the previously formed C-OcarbH group.
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Affiliation(s)
- Mohamed M Aboelnga
- Department of Chemistry and Biochemistry, University of Windsor , Windsor, Ontario N9B 3P4, Canada.,Department of Chemistry, Faculty of Science, Damietta University , New Damietta, Damietta Governorate 34511, Egypt
| | - John J Hayward
- Department of Chemistry and Biochemistry, University of Windsor , Windsor, Ontario N9B 3P4, Canada
| | - James W Gauld
- Department of Chemistry and Biochemistry, University of Windsor , Windsor, Ontario N9B 3P4, Canada
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10
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Aboelnga MM, Hayward JJ, Gauld JW. Enzymatic Post-Transfer Editing Mechanism of E. coli Threonyl-tRNA Synthetase (ThrRS): A Molecular Dynamics (MD) and Quantum Mechanics/Molecular Mechanics (QM/MM) Investigation. ACS Catal 2017. [DOI: 10.1021/acscatal.7b01554] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Mohamed M. Aboelnga
- Department
of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
- Department
of Chemistry, Faculty of Science, University of Damietta, New Damietta, Damietta Governorate 34511, Egypt
| | - John J. Hayward
- Department
of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B 3P4, Canada
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11
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Aboelnga MM, Hayward JJ, Gauld JW. A water-mediated and substrate-assisted aminoacylation mechanism in the discriminating aminoacyl-tRNA synthetase GlnRS and non-discriminating GluRS. Phys Chem Chem Phys 2017; 19:25598-25609. [DOI: 10.1039/c7cp02969a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Computational methods have been used to elucidate key differences and similarities between the distinct aminoacyl-tRNA synthetases (aaRS) GlnRS and non-discriminating-GluRS.
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Affiliation(s)
- Mohamed M. Aboelnga
- Department of Chemistry and Biochemistry
- University of Windsor
- Windsor
- Canada
- Department of Chemistry and Biochemistry
| | - John J. Hayward
- Department of Chemistry and Biochemistry
- University of Windsor
- Windsor
- Canada
| | - James W. Gauld
- Department of Chemistry and Biochemistry
- University of Windsor
- Windsor
- Canada
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12
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Rycek L, Hayward JJ, Latif MA, Tanko J, Simionescu R, Hudlicky T. Chemoenzymatic Total Synthesis of Hydromorphone by an Oxidative Dearomatization/Intramolecular [4 + 2] Cycloaddition Sequence: A Second-Generation Approach. J Org Chem 2016; 81:10930-10941. [PMID: 27690149 DOI: 10.1021/acs.joc.6b01990] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A second-generation approach to the synthesis of hydromorphone by oxidative dearomatization/Diels-Alder cycloaddition was investigated. Detailed analysis of the stereochemical outcome of the [4 + 2] cycloaddition was performed first on a truncated model system as well as on the material leading to ent-hydromorphone. The stereochemical assignments were made by NMR and X-ray methods. The second-generation synthesis of hydromorphone was completed in both enantiomeric series. Improvements in the dearomatization conditions were attained using hypervalent iodine reagents instead of Pb(OAc)4. Electrochemical methods of oxidative dearomatization were also investigated. New conditions enabling the rearomatization of ring A from the methoxyketal were developed, and a formal synthesis of the natural enantiomer of hydromorphone was completed. Experimental and spectral data are provided for all new compounds.
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Affiliation(s)
- Lukas Rycek
- Department of Chemistry and Centre for Biotechnology, Brock University , 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - John J Hayward
- Department of Chemistry and Centre for Biotechnology, Brock University , 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Marwa Abdel Latif
- Department of Chemistry, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - James Tanko
- Department of Chemistry, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Razvan Simionescu
- Department of Chemistry and Centre for Biotechnology, Brock University , 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Tomas Hudlicky
- Department of Chemistry and Centre for Biotechnology, Brock University , 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
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13
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Wrixon JD, Hayward JJ, Rawson JM. Phosphine Control of the Oxidative Addition Chemistry of Tetrathiocins to Palladium(0): Characterization of Mono-, Di-, and Hexanuclear Palladium(II) Dithiolate Complexes. Inorg Chem 2015; 54:9384-6. [DOI: 10.1021/acs.inorgchem.5b01555] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Justin D. Wrixon
- Department
of Chemistry and Biochemistry, University of Windsor, 401 Sunset
Avenue, Windsor, Ontario N9B3P4, Canada
| | - John J. Hayward
- Department
of Chemistry and Biochemistry, University of Windsor, 401 Sunset
Avenue, Windsor, Ontario N9B3P4, Canada
| | - Jeremy M. Rawson
- Department
of Chemistry and Biochemistry, University of Windsor, 401 Sunset
Avenue, Windsor, Ontario N9B3P4, Canada
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14
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Clark ER, Hayward JJ, Leontowicz BJ, Anwar MU, Pilkington M, Rawson JM. Copper-promoted aerial oxidation of benzothiadiazines: access to benzothiadiazine S-oxide heterocycles. Dalton Trans 2015; 44:2071-4. [PMID: 25563651 DOI: 10.1039/c4dt03467h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cu(II)-promoted aerial oxidation of a series of benzothiadiazines () under ambient conditions affords the first structurally characterised examples of thiadiazine S-oxides (). The isolation of the homoleptic Cu(II) 3-(2'-pyridyl)benzothiadiazide-S-oxide complex provides insight into the reaction mechanism.
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Affiliation(s)
- Ewan R Clark
- Department of Chemistry, The University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
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15
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Wang J, Hayward JJ, Gumbau-Brisa R, Wallis JD, Stoeckli-Evans H, Pilkington M. Probing the reactivity of a 2,2′-bipyridyl-3,3′-bis-imine ligand by X-ray crystallography. CrystEngComm 2015. [DOI: 10.1039/c4ce01952k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Abstract
Ketiminoboranes, R2CNB-R′2, pioneered by Wade et al., are formally isoelectronic with allenes but undergo intramolecular cyclisation when R = 2-pyridyl to form heterocyclic boranes with N-donor capability.
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Affiliation(s)
| | - Liz Mansour
- Department of Chemistry & Biochemistry
- The University of Windsor
- Windsor
- Canada N9B 3P4
| | - John J. Hayward
- Department of Chemistry & Biochemistry
- The University of Windsor
- Windsor
- Canada N9B 3P4
| | - Jeremy M. Rawson
- Department of Chemistry & Biochemistry
- The University of Windsor
- Windsor
- Canada N9B 3P4
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17
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Hurley NJ, Hayward JJ, Rawson JM, Murrie M, Pilkington M. Exploring the Coordination Chemistry of 3,3′-Di(picolinamoyl)-2,2′-bipyridine: One Ligand, Multiple Nuclearities. Inorg Chem 2014; 53:8610-23. [DOI: 10.1021/ic501224q] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Nicholas J. Hurley
- Department
of Chemistry, Brock University, 500 Glenridge Ave, St Catharines, Ontario, Canada L2S 3A1
| | - John J. Hayward
- Department
of Chemistry, Brock University, 500 Glenridge Ave, St Catharines, Ontario, Canada L2S 3A1
| | - Jeremy M. Rawson
- Department of Chemistry
and Biochemistry, University of Windsor, 401 Sunset Ave., Windsor, Ontario, Canada N9B 3P4
| | - Mark Murrie
- School of Chemistry, Joseph Black Building, University Ave, Glasgow, Lanarkshire G12 8QQ, United Kingdom
| | - Melanie Pilkington
- Department
of Chemistry, Brock University, 500 Glenridge Ave, St Catharines, Ontario, Canada L2S 3A1
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Clark ER, Anwar MU, Leontowicz BJ, Beldjoudi Y, Hayward JJ, Chan WTK, Gavey EL, Pilkington M, Zysman-Colman E, Rawson JM. Synthesis and characterisation of first row transition metal complexes of functionalized 1,2,4-benzothiadiazines. Dalton Trans 2014; 43:12996-3005. [DOI: 10.1039/c4dt01413h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Affiliation(s)
- Hugh J Cowley
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, CanadaN9B 3P4.
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Abstract
An octanuclear copper(ii) cluster assembled from a large, flexible polydentate ligand reveals an unusual saddle-shaped structural topology.
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Affiliation(s)
- Niloofar Zarrabi
- Department of Chemistry
- Brock University
- St Catharines, L2S 3A1 Canada
| | - John J. Hayward
- Department of Chemistry
- Brock University
- St Catharines, L2S 3A1 Canada
| | - William Clegg
- School of Chemistry
- Bedson Building
- Newcastle University
- Newcastle upon Tyne, UK
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Clark ER, Hayward JJ, Leontowicz BJ, Eisler DJ, Rawson JM. Syntheses of, and structural studies on, benzo-fused 1,2,4-thiadiazines. CrystEngComm 2014. [DOI: 10.1039/c3ce42205d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Hayward JJ, Gumbau-Brisa R, Alberola A, Clarke CS, Rawson JM, Pilkington M. An unusual single-crystal-to-single-crystal [2 + 2] photocyclisation reaction of a TTF-arylnitrile derivative. CrystEngComm 2014. [DOI: 10.1039/c4ce00346b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Irradiation of single crystals of a benzonitrile substituted tetrathiafulvalene with polychromatic light results in a [2 + 2] cycloaddition reaction.
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Affiliation(s)
- John J. Hayward
- Department of Chemistry
- Brock University
- St. Catharines, Canada
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Wrixon JD, Hayward JJ, Raza O, Rawson JM. Oxidative addition chemistry of tetrathiocines: synthesis, structures and properties of group 10 dithiolate complexes. Dalton Trans 2014; 43:2134-9. [DOI: 10.1039/c3dt52802b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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24
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Beldjoudi Y, Haynes DA, Hayward JJ, Manning WJ, Pratt DR, Rawson JM. Preparation and crystal structures of the isomeric series 4-tolyl-1,2,3,5-dithiadiazolyl, (o-MeC6H4CNSSN)2, (m-MeC6H4CNSSN)2and (p-MeC6H4CNSSN)2. CrystEngComm 2013. [DOI: 10.1039/c2ce26431e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The pharmaceutical industry is under increasing pressure on many fronts, from investors requiring larger returns to consumer groups and health authorities demanding cheaper and safer drugs. It is also feeling additional pressure from the infringement upon its profit margins by generic drug producers. Many companies are aggressively pursuing outsourcing contracts in an attempt to counter many of the financial pressures and streamline their operations. At the same time, the productivity of the pharmaceutical industry at its science base is being questioned in terms of the number of products and the timeframes required for each company to deliver them to market. This has generated uncertainties regarding the current corporate strategies that have been adopted and the levels of innovation being demonstrated. In this essay we discuss these topics in the context of the global pharmaceutical market, investigating the basis for many of these issues and highlighting the hurdles the industry needs to overcome, especially as they relate to the chemical sciences.
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Affiliation(s)
- Ian R Baxendale
- Innovative Technology Centre, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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Smith CD, Baxendale IR, Lanners S, Hayward JJ, Smith SC, Ley SV. [3 + 2] Cycloaddition of acetylenes with azides to give 1,4-disubstituted 1,2,3-triazoles in a modular flow reactor. Org Biomol Chem 2007; 5:1559-61. [PMID: 17571184 DOI: 10.1039/b702995k] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [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: 11/21/2022]
Abstract
The cycloaddition of acetylenes with azides to give the corresponding 1,4-disubstituted 1,2,3-triazoles is reported using immobilised reagents and scavengers in pre-packed glass tubes in a modular flow reactor.
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Affiliation(s)
- Christopher D Smith
- Innovative Technology Centre (ACS), Department of Chemistry, Lensfield Road, Cambridge, CB2 1EW, UK
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27
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Cunningham ML, Hayward JJ, Shane BS, Tindall KR. Distinction of mutagenic carcinogens from a mutagenic noncarcinogen in the big blue transgenic mouse. Environ Health Perspect 1996; 104 Suppl 3:683-686. [PMID: 8781405 PMCID: PMC1469641 DOI: 10.1289/ehp.96104s3683] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The aromatic amines 2,4-diaminotoluene (2,4-DAT) and 2,6-diaminotoluene (2,6-DAT) are structural isomers that have been extensively studied for their mutagenic and carcinogenic characteristics. Both compounds are rapidly absorbed after oral administration and are equally mutagenic in the Ames test; however, 2,4-DAT is a potent hepatocarcinogen, whereas 2,6-DAT does not produce an increased incidence of tumors in rats or mice at similar doses. The Big Blue transgenic B6C3F1 mouse carries multiple copies of the lacl mutational target gene. Our studies were designed to determine whether the Big Blue system could be used to detect differences in the vivo mutagenic activity between the carcinogen-noncarcinogen pair 2,4-DAT and 2,6-DAT and to determine whether the in vivo mutagenesis assay results correspond to the rodent carcinogen bioassay results. Male B6C3F1 transgenic mice were exposed to 2,4-DAT or 2,6-DAT at 0 or 1,000 ppm in the diet for 30 and 90 days or to dimethylnitrosamine as a positive control. Mutant frequencies were nearly identical for all three groups at 30 days, while at 90 days the mutant frequency for the hepatocarcinogen 2,4-DAT (12.1 +/- 1.4 x 10(-5)) was significantly higher (p < 0.01) as compared to both age-matched (spontaneous) controls (5.7 +/- 2.9 x 10(-5)) and the 2,6-DAT-exposed group (5.7 +/- 2.4 x 10(-5)). Results from this study demonstrate that the Big Blue transgenic mutation assay can distinguish differences in vivo between the mutagenic responses of hepatic carcinogens ad a noncarcinogen; is sensitive to mutagens through subchronic dietary exposure; and yields a differential response depending upon the length of time mice are exposed to a mutagen.
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Affiliation(s)
- M L Cunningham
- Environmental Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA.
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Hayward JJ, Shane BS, Tindall KR, Cunningham ML. Differential in vivo mutagenicity of the carcinogen/non-carcinogen pair 2,4- and 2,6-diaminotoluene. Carcinogenesis 1995; 16:2429-33. [PMID: 7586147 DOI: 10.1093/carcin/16.10.2429] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [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: 01/26/2023] Open
Abstract
The aromatic amines 2,4-diaminotoluene (2,4-DAT) and 2,6-diaminotoluene (2,6-DAT) are structural isomers that have been extensively studied for their mutagenic and carcinogenic characteristics. Both compounds are equally mutagenic in the Ames/Salmonella assay in the presence of S9. However, the differences in the results of chronic rodent carcinogen bioassays using these two compounds are significant, in that 2,4-DAT is a potent hepatocarcinogen, whereas 2,6-DAT does not produce an increased incidence of tumors in rats or mice at similar doses. The Big Blue transgenic B6C3F1 mouse carries multiple copies of bacteriophage lambda, each with a lacI mutational target gene, integrated into mouse chromosome 4. Our studies were designed to determine whether the Big Blue system could be used to detect differences in the in vivo mutagenic activity between the carcinogen/non-carcinogen pair 2,4- and 2,6-DAT and to determine whether the in vivo mutagenesis assay results correspond to the rodent carcinogen bioassay results. Male B6C3F1 transgenic mice were exposed to 2,4- or 2,6-DAT at 0 or 1000 p.p.m. in the diet for 30 and 90 days. Mice serving as positive controls were administered five daily i.p. injections of 6 mg/kg dimethylnitrosamine (DMN) in saline and were sacrificed 15 days following the last injection. Mutant frequencies at lacI were determined by recovering the genomically integrated lambda phage using an in vitro packaging reaction followed by infection of an appropriate Escherichia coli host. Complete non-sectored blue mutant plaques were scored against a background of clear non-mutant plaques. Mutant frequencies were nearly identical for all three groups at 30 days, while at 90 days the mutant frequency for the hepatocarcinogen 2,4-DAT (12.1 +/- 1.4 x 10(-5)) was significantly higher (P < 0.01) as compared with both age-matched (spontaneous) controls (5.7 +/- 2.9 x 10(-5)) and the 2,6-DAT-exposed group (5.7 +/- 2.4 x 10(-5)). Mutations at lacI arising ex vivo during replication in E. coli are observed in this system as sectored blue plaques. The sectored plaque frequency in this study was constant across all groups at approximately 9.0 x 10(-5). Results from this study demonstrate that the Big Blue transgenic mutation assay: (i) can distinguish differences in vivo between the mutagenic responses of a carcinogen and a non-carcinogen which elicited comparable mutagenic activity in S.typhimurium; (ii) is sensitive to mutagens through subchronic dietary exposure; and (iii) yields a differential response depending upon the length of time mice are exposed to a mutagen.
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Affiliation(s)
- J J Hayward
- Environmental Toxicology Program, National Institute of Environmental Health Sciences, Research, Triangle Park, NC 27709, USA
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Johnson JA, Hayward JJ, Kornguth SE, Siegel FL. Effects of hyperbilirubinaemia on glutathione S-transferase isoenzymes in cerebellar cortex of the Gunn rat. Biochem J 1993; 291 ( Pt 2):453-61. [PMID: 8484726 PMCID: PMC1132547 DOI: 10.1042/bj2910453] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The glutathione S-transferases (GSTs) are a family of isoenzymes involved in the detoxication of a variety of electrophilic xenobiotics. The present investigation demonstrates that GST activity and the concentration of cytosolic GSTs in cerebellar cortex of Gunn rats were increased in hyperbilirubinaemic animals compared with non-jaundiced controls. Age-dependent and region-specific increases in GST isoenzymes were seen in three regions of the cerebellar cortex of jaundiced Gunn rats, whereas GST concentrations were not altered in the brainstem, thalamus/hypothalamus, cortex or liver. Cytosolic GST activity was increased 1.3-fold in the flocculus and lateral hemispheres of 20-day-old and 1.7-fold in the flocculus, lateral hemispheres and vermis of 60-day-old jaundiced (jj; homozygous) Gunn rats compared with non-jaundiced (Jj; heterozygous) Gunn rats. H.p.l.c. was used to determine the GST subunit protein concentrations in cytosolic fractions isolated from liver and brain regions of jaundiced and non-jaundiced animals. In all regions of the cerebellum from 20-day-old animals, the levels of Alpha-class GST subunits 2 (Yc1; 3.0-fold) and 8 (Yk; 2.0-fold) were increased in jaundiced rats. In 60-day-old animals, the concentrations of Alpha-class GST subunits 2 (Yc1; 5.0-fold) and 8 (Yk; 3.0-fold), Mu-class subunit 11 (Yo; 2.5-fold) and Pi-class subunit 7 (Yp; 2.0-fold) were increased in all regions of cerebellar cortex of jaundiced animals. In cerebellum of 10-, 20- and 60-day-old non-jaundiced and jaundiced Gunn rats, the flocculus had the highest concentration of Mu-class GST subunit 4 (Yb2) and vermis the lowest; hyperbilirubinaemia increased the concentration of subunit 4 (Yb2; 3- to 5-fold) in the flocculus and lateral hemispheres, but not the vermis, of 20- and 60-day-old rats. Intraperitoneal injection of sulphadimethoxine, a long-acting sulphonamide which displaces bilirubin from its albumin-binding sites and increases the bilirubin levels in tissues, further increased the already elevated concentrations of GST subunits in the lateral regions of cerebellar cortex of hyperbilirubinaemic rats. For example, the concentration of subunit 4 (Yb2) was increased 2.2-fold (compared with non-jaundiced controls) in Gunn rats injected with saline and 7.4-fold in rats injected with 100 mg of sulphadimethoxine/kg body weight. In contrast, GSTs in the vermis of jaundiced animals were not affected by sulphadimethoxine injection. Sulphadimethoxine had no effect on GST concentrations in lateral regions and vermis of heterozygous (Jj) Gunn rats.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J A Johnson
- Environmental Toxicology Center, Waisman Center, University of Wisconsin, Madison 53706
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