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Synthesis of Coumarin Derivatives: A New Class of Coumarin-Based G Protein-Coupled Receptor Activators and Inhibitors. Polymers (Basel) 2022; 14:polym14102021. [PMID: 35631901 PMCID: PMC9147790 DOI: 10.3390/polym14102021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 02/01/2023] Open
Abstract
To expand the range of daphnetin-based inhibitors/activators used for targeting G protein-coupled receptors (GPCRs) in disease treatment, twenty-five coumarin derivatives 1–25, including 7,8-dihydroxycoumarin and 7-hydroxycoumarin derivatives with various substitution patterns/groups at C3-/4- positions, were synthesized via mild Pechmann condensation and hydroxyl modification. The structures were characterized by 1H NMR, 13C NMR and ESI-MS. Their inhibition or activation activities relative to GPCRs were evaluated by double-antibody sandwich ELISA (DAS–ELISA) in vitro. The results showed that most of the coumarin derivatives possessed a moderate GPCR activation or inhibitory potency. Among them, derivatives 14, 17, 18, and 21 showed a remarkable GPCR activation potency, with EC50 values of 0.03, 0.03, 0.03, and 0.02 nM, respectively. Meanwhile, derivatives 4, 7, and 23 had significant GPCR inhibitory potencies against GPCRs with IC50 values of 0.15, 0.02, and 0.76 nM, respectively. Notably, the acylation of hydroxyl groups at the C-7 and C-8 positions of 7,8-dihydroxycoumarin skeleton or the etherification of the hydroxyl group at the C-7 position of the 7-hydroxycoumarin skeleton could successfully change GPCRs activators into inhibitors. This work demonstrated a simple and efficient approach to developing coumarin derivatives as remarkable GPCRs activators and inhibitors via molecular diversity-based synthesis.
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2
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Asymmetric and symmetric triazenido cyclopalladated complexes: Synthesis, structural analysis and DFT calculations. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2014.11.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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3
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Blinov V, Volchek K, Kuang W, Bhalerao A, Brown CE. Decontamination of Paraoxon and Parathion on Sensitive Equipment Materials by Catalytic Methanolysis. Ind Eng Chem Res 2014. [DOI: 10.1021/ie502427y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vladimir Blinov
- Environment Canada, 335 River Road, Ottawa, Ontario K1A 0H3, Canada
| | | | - Wenxing Kuang
- Environment Canada, 335 River Road, Ottawa, Ontario K1A 0H3, Canada
| | - Akshay Bhalerao
- Environment Canada, 335 River Road, Ottawa, Ontario K1A 0H3, Canada
| | - Carl E. Brown
- Environment Canada, 335 River Road, Ottawa, Ontario K1A 0H3, Canada
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Neverov AA, Chen LD, George S, Simon D, Maxwell CI, Brown RS. A mechanistic study of the [La2(OCH3)2]4+- and [(1,5,9-triazacyclodo-decane):Zn:(OCH3)]+-catalyzed methanolysis of carbonates: possible application for the recycling of bisphenol A polycarbonates. CAN J CHEM 2013. [DOI: 10.1139/cjc-2013-0270] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The kinetics of the methanolysis of seven methyl aryl carbonates (3) and two methyl alkyl carbonates (4) promoted by [12[ane]N3:Zn:(OCH3)]+ and [La2(OCH3)2]4+ catalysts (1 and 2, respectively) have been studied at 25.0 °C. Brønsted plots of the [Formula: see text] values for methanolysis versus aryloxy and alkoxy leaving group (LG) [Formula: see text] or [Formula: see text] values (the pKa values of the parent ArOH or ROH in methanol) for substrates 3 and 4 show an apparent downward break at [Formula: see text] ∼16.6 and 15.2 with [12[ane]N3:Zn:(OCH3)]+ and [La2(OCH3)2]4+, respectively. The breakpoint is not due to a change in rate-limiting step in a two-step process involving metal ion delivery of a coordinated methoxide to a transiently associated substrate and the subsequent breakdown of a tetrahedral intermediate to form product. The more satisfactory explanation is that the break arises when one correlates the rate constants for two dissimilar sets of substrates, namely aryloxy- and alkoxy-substituted 3 and 4. DFT calculations for the 1-promoted reactions of methyl 4-nitrophenyl carbonate (3b), which has a good aryloxy leaving group, and methyl isopropyl carbonate (4b), which has a relatively poor alkyl one, indicate that the catalyzed processes involve two steps. Accordingly, the methanolysis of all 3 having [Formula: see text] values for the parent phenols ≤15.3 involves rate-limiting nucleophilic attack and fast breakdown. For the isopropyl alkyl derivative (4b) having a [Formula: see text] > 18.13, the rate-liming step is the metal ion promoted breakdown of a tetrahedral intermediate. The catalytic system employing 2 has utility for the catalytic decomposition of poly(bisphenol A carbonate). In a semi-optimized system where 1000 mg of poly(bisphenol A carbonate), treated at 100 °C for 30 min in 2 mL of 60:40 chloroform−methanol containing La(OTf)3:NaOMe (5:7.5 mmol L−1), the reaction gave an 84% yield of bisphenol A, corresponding to >300 turnovers per catalyst.
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Affiliation(s)
- Alexei A. Neverov
- Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Leanne D. Chen
- Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Sean George
- Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - David Simon
- Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6, Canada
| | | | - R. Stan Brown
- Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6, Canada
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Synthesis and immobilization of oxime-derived palladacycles as effective and reusable catalysts for the degradation of phosphorothionate pesticides. INORG CHEM COMMUN 2013. [DOI: 10.1016/j.inoche.2013.04.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Blinov V, Volchek K, Kuang W, Brown CE, Bhalerao A. Two-Stage Decontamination of Organophosphorus Compounds on Sensitive Equipment Materials. Ind Eng Chem Res 2013. [DOI: 10.1021/ie302012y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vladimir Blinov
- Environment Canada, 335
River Road, Ottawa, Ontario, K1A 0H3, Canada
| | | | - Wenxing Kuang
- Environment Canada, 335
River Road, Ottawa, Ontario, K1A 0H3, Canada
| | - Carl E. Brown
- Environment Canada, 335
River Road, Ottawa, Ontario, K1A 0H3, Canada
| | - Akshay Bhalerao
- Environment Canada, 335
River Road, Ottawa, Ontario, K1A 0H3, Canada
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Liu T, Cui X, Yu Z, Li C. A New Method of Introducing SCH3and SCD3Groups to Phosphorothioates. PHOSPHORUS SULFUR 2012. [DOI: 10.1080/10426507.2011.634467] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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8
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Development of metal-ion containing catalysts for the decomposition of phosphorothioate esters. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1834:433-42. [PMID: 22381961 DOI: 10.1016/j.bbapap.2012.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 02/08/2012] [Accepted: 02/11/2012] [Indexed: 11/23/2022]
Abstract
The widespread use of phosphorothioate esters as agricultural pesticides, chemical weapons and mechanistic probes in enzymology has sparked interest in the reactivity of these thio-substituted analogues of phosphate esters. In this brief account, we summarize the recent developments in our understanding of the mechanisms of hydrolysis (and solvolysis in methanol) of phosphorothioates containing a sulfur atom in the bridging and/or non-bridging position. A small number of highly efficient catalytic systems containing the metal ions La(III), Pd(II), Cu(II) and Zn(II) have been developed to promote the degradation of the various classes of phosphorothioate esters. The mechanisms of the base promoted solvolytic reactions in water and methanol and those of the metal catalyzed cleavage are presented, as well as a discussion of the energetics of the catalytic processes and other salient features. The aim of this review is to provide the reader with a contemporary physical organic description of phosphorothioate ester cleavage. This article is part of a Special Issue entitled: Chemistry and mechanism of phosphatases, diesterases and triesterases.
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Maxwell CI, Liu CT, Neverov AA, Mosey NJ, Brown RS. Transition from concerted to stepwise processes as a function of leaving group ability: density functional theory and experimental study of lyoxide-promoted cleavages of phosphorothioate and phosphate triesters in water and methanol. J PHYS ORG CHEM 2011. [DOI: 10.1002/poc.1938] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - C. Tony Liu
- Department of Chemistry; Queen's University; Kingston Ontario Canada K7L 3N6
| | - Alexei A. Neverov
- Department of Chemistry; Queen's University; Kingston Ontario Canada K7L 3N6
| | - Nicholas J. Mosey
- Department of Chemistry; Queen's University; Kingston Ontario Canada K7L 3N6
| | - Robert Stan Brown
- Department of Chemistry; Queen's University; Kingston Ontario Canada K7L 3N6
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Edwards DR, Maxwell CI, Harkness RW, Neverov AA, Mosey NJ, Stan Brown R. Experimental and computational determination of Brønsted coefficients for equilibrium transfer of the O
,O
-dimethyl phosphorothioyl group between oxyanion nucleophiles. J PHYS ORG CHEM 2011. [DOI: 10.1002/poc.1903] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- David R. Edwards
- Department of Chemistry; Queen's University; Kingston Ontario K7L 3N6 Canada
| | | | - Robert W. Harkness
- Department of Chemistry; Queen's University; Kingston Ontario K7L 3N6 Canada
| | - Alexei A. Neverov
- Department of Chemistry; Queen's University; Kingston Ontario K7L 3N6 Canada
| | - Nicholas J. Mosey
- Department of Chemistry; Queen's University; Kingston Ontario K7L 3N6 Canada
| | - R. Stan Brown
- Department of Chemistry; Queen's University; Kingston Ontario K7L 3N6 Canada
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11
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Liu CT, Neverov AA, Brown RS. Palladacycle-Promoted Solvolytic Cleavage of O,O-Dimethyl O-Aryl Phosphorothioates. Converting a Phosphorane-Like Transition State to an Observable Intermediate. Inorg Chem 2011; 50:7852-62. [DOI: 10.1021/ic201062h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- C. Tony Liu
- Department of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Alexei A. Neverov
- Department of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - R. Stan Brown
- Department of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
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Edwards DR, Neverov AA, Brown RS. Study on the Transesterification of Methyl Aryl Phosphorothioates in Methanol Promoted by Cd(II), Mn(II), and a Synthetic Pd(II) Complex. Inorg Chem 2011; 50:1786-97. [DOI: 10.1021/ic102220m] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David R. Edwards
- Department of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Alexei A. Neverov
- Department of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - R. Stan Brown
- Department of Chemistry, Queen’s University, Kingston, Ontario K7L 3N6, Canada
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Dey NK, Kim CK, Lee HW. Kinetics and mechanism of the anilinolyses of aryl dimethyl, methyl phenyl and diphenyl phosphinates. Org Biomol Chem 2011; 9:717-24. [DOI: 10.1039/c0ob00517g] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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14
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Clements JW, Stojanovic M, Hoffman NW, Sykora RE. Chlorido{2-[(dimethylamino)methyl]phenyl-κ 2C1, N}(1-methyl-1 H-imidazole-κ N3)palladium(II). Acta Crystallogr Sect E Struct Rep Online 2010; 66:m1639-40. [PMID: 21589311 PMCID: PMC3011615 DOI: 10.1107/s1600536810047367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 11/15/2010] [Indexed: 11/12/2022]
Abstract
In the title compound, [Pd(C9H12N)Cl(C4H6N2)], which was synthesized from the reaction of 1-methylimidazole with dimeric dichloridobis[2-(dimethylamino)benzyl]palladium(II), the ring-deprotonated N,N-dimethylbenzylamine ligand acts in a C,N-bidentate fashion. The dihedral angle between the ring of the 1-methylimidazole ligand and the palladacycle plane is 57.88 (16)°. The two N atoms from the N,N-dimethylbenzylamine and 1-methylimidazole ligands are trans coordinated to the PdII atom.
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Liu CT, Maxwell CI, Edwards DR, Neverov AA, Mosey NJ, Brown RS. Mechanistic and Computational Study of a Palladacycle-Catalyzed Decomposition of a Series of Neutral Phosphorothioate Triesters in Methanol. J Am Chem Soc 2010; 132:16599-609. [DOI: 10.1021/ja107144c] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Tony Liu
- Department of Chemistry, Queen’s University, Kingston, Ontario, Canada K7L 3N6
| | | | - David R. Edwards
- Department of Chemistry, Queen’s University, Kingston, Ontario, Canada K7L 3N6
| | - Alexei A. Neverov
- Department of Chemistry, Queen’s University, Kingston, Ontario, Canada K7L 3N6
| | - Nicholas J. Mosey
- Department of Chemistry, Queen’s University, Kingston, Ontario, Canada K7L 3N6
| | - R. Stan Brown
- Department of Chemistry, Queen’s University, Kingston, Ontario, Canada K7L 3N6
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16
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Lu ZL, Wang XR, Liu BB, Wang RY. Palladacycles with C,N-bidentate and N,C,N′-tridentate ligands: Structures, spectral study and catalytic methanolysis of PS pesticides. J Organomet Chem 2010. [DOI: 10.1016/j.jorganchem.2010.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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17
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Liu BB, Wang XR, Guo ZF, Lu ZL. Mononuclear versus dinuclear palladacycles derived from 1,3-bis(N,N-dimethylaminomethyl)benzene: Structures and catalytic activity. INORG CHEM COMMUN 2010. [DOI: 10.1016/j.inoche.2010.03.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Lu ZL, Yang XS, Guo ZF, Wang RY. (S)-4-tert-Butyl-2-phenyl-2-oxazoline derived palladacycles as efficient catalysts for the decomposition of P=S pesticides. J COORD CHEM 2010. [DOI: 10.1080/00958972.2010.491545] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Zhong-Lin Lu
- a College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Xiao-Sheng Yang
- a College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Zhi-Fo Guo
- a College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Rui-Yao Wang
- b Department of Chemistry , Queen's University , Kingston, ON, K7L 3N6, Canada
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Lu ZL, Yang XS, Wang RY, Fun HK, Chantrapromma S. Substituted pyridine coordinated N,N-trans and N,N-cis cyclopalladated complexes of (S)-4-tert-butyl-2-phenyl-2-oxazoline: Crystal structures, spectral study and catalysis of the decomposition of PS pesticides. Polyhedron 2009. [DOI: 10.1016/j.poly.2009.05.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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20
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Yang XS, Long DL, Li HM, Lu ZL. Synthesis, structures and catalytic properties of palladacycles derived from N,N-dimethylaminomethylferrocene. INORG CHEM COMMUN 2009. [DOI: 10.1016/j.inoche.2009.04.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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21
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Um IH, Han JY, Shin YH. Aminolysis of X-Substituted Phenyl Diphenylphosphinates: Effect of Amine Nature on Reactivity and Transition-State Structure. J Org Chem 2009; 74:3073-8. [DOI: 10.1021/jo900219t] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ik-Hwan Um
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
| | - Jeong-Yoon Han
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
| | - Young-Hee Shin
- Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
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Mohamed MF, Neverov AA, Brown RS. An Immobilized Ortho-Palladated Dimethylbenzylamine Complex as an Efficient Catalyst for the Methanolysis of Phosphorothionate Pesticides. Inorg Chem 2008; 48:1183-91. [DOI: 10.1021/ic801382e] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mark F. Mohamed
- Department of Chemistry, Queen’s University, Chernoff Hall, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - Alexei A. Neverov
- Department of Chemistry, Queen’s University, Chernoff Hall, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
| | - R. Stan Brown
- Department of Chemistry, Queen’s University, Chernoff Hall, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada
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23
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Reaction Mechanism and Structure of Transition State Determined from Analysis of Bronsted βnucfor Aminolysis of 4-Nitrophenyl Diphenylphosphinate. B KOREAN CHEM SOC 2008. [DOI: 10.5012/bkcs.2008.29.12.2509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Um IH, Han JY, Hwang SJ. Analysis of Linear Free-Energy Relationships Combined with Activation Parameters Assigns a Concerted Mechanism to Alkaline Hydrolysis of X-Substituted Phenyl Diphenylphosphinates. Chemistry 2008; 14:7324-30. [DOI: 10.1002/chem.200800553] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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25
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Ruiz J, Lorenzo J, Vicente C, López G, María López-de-Luzuriaga J, Monge M, Avilés FX, Bautista D, Moreno V, Laguna A. New palladium(II) and platinum(II) complexes with 9-aminoacridine: structures, luminiscence, theoretical calculations, and antitumor activity. Inorg Chem 2008; 47:6990-7001. [PMID: 18593114 DOI: 10.1021/ic800589m] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The new complexes [Pd(dmba)( N10-9AA)(PPh 3)]ClO 4 ( 1), [Pt(dmba)( N9-9AA)(PPh 3)]ClO 4 ( 2), [Pd(dmba)( N10-9AA)Cl] ( 3), and [Pd(C 6F 5)( N10-9AA)(PPh 3)Cl] ( 4) (9-AA = 9-aminoacridine; dmba = N,C-chelating 2-(dimethylaminomethyl)phenyl) have been prepared. The crystal structures have been established by X-ray diffraction. In complex 2, an anagostic C-H...Pt interaction is observed. All complexes are luminescent in the solid state at room temperature, showing important differences between the palladium and platinum complexes. Complex 2 shows two structured emission bands at high and low energies in the solid state, and the lifetimes are in agreement with excited states of triplet parentage. Density functional theory and time-dependent density functional theory calculations for complex 2 have been done. Values of IC 50 were also calculated for the new complexes 1- 4 against the tumor cell line HL-60. All of the new complexes were more active than cisplatin (up to 30-fold in some cases). The DNA adduct formation of the new complexes synthesized was followed by circular dichroism and electrophoretic mobility. Atomic force microscopy images of the modifications caused by the complexes on plasmid DNA pB R322 were also obtained.
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Affiliation(s)
- José Ruiz
- Departamento de Quimica Inorganica, Universidad de Murcia, E-30071 Murcia, Spain.
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Li HM, Su JG, Lu ZL, Fun HK, Chantrapromma S. Palladacycle complexes of (S)-4-iso-propyl-2-phenyl-2-oxazoline: Synthesis, crystal structures and catalytical methanolysis of pesticide. INORG CHEM COMMUN 2008. [DOI: 10.1016/j.inoche.2007.11.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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27
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Gong JF, Xu C, Zhang YH, Zhu Y, Wu YJ. Synthesis, characterization and crystal structures of two cis/trans pyridine-cyclopalladated ferrocenylimine complexes. TRANSIT METAL CHEM 2007. [DOI: 10.1007/s11243-007-0285-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Liu CT, Neverov AA, Brown RS. A Reductionist Biomimetic Model System That Demonstrates Highly Effective Zn(II)-Catalyzed Cleavage of an RNA Model. Inorg Chem 2007; 46:1778-88. [PMID: 17256929 DOI: 10.1021/ic062065u] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cyclization of the RNA model 2-hydroxypropyl p-nitrophenyl phosphate (HPNPP, 1) promoted by Zn2+ alone and the 1,5,9-triazacyclododecane complex of Zn2+ (Zn2+:[12]aneN3) is studied in ethanol in the presence of 0.5 equiv of -OEt/Zn2+ to investigate the effect of a low polarity/dielectric medium on a metal-catalyzed reaction of biological relevance. Ethanol exerts a medium effect that promotes strong binding of HPNPP to Zn2+, followed by a dimerization to form a catalytically active complex (HPNPP:Zn2+)2 in which the phosphate undergoes cyclization with a rate constant of kcat = 2.9 s(-1) at s(s)pH 7.1. In the presence of the triaza ligand:Zn2+ complex, the change from water to methanol and then to ethanol brings about a mechanism where two molecules of the complex, suggested as EtOH:Zn2+:[12]aneN3 and its basic form, EtO-:Zn2+:[12]aneN3, bind to HPNPP and catalyze its decomposition with a rate constant of kcat of 0.13 s(-1) at s(s)pH 7.1. Overall, the acceleration exhibited in these two situations is 4 x 10(14)-fold and 1.7 x 10(12)-fold relative to the background ethoxide-promoted reactions at the respective s(s)pH values. The implications of these findings are discussed within the context of the idea that enzymatic catalysis is enhanced by a reduced effective dielectric constant within the active site.
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Affiliation(s)
- C Tony Liu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada
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Um IH, Park JE, Shin YH. Combined dual substituent constant and activation parameter analysis assigns a concerted mechanism to alkaline ethanolysis at phosphorus of Y-substituted phenyl diphenylphosphinates. Org Biomol Chem 2007; 5:3539-43. [DOI: 10.1039/b712427a] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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31
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Xu C, Gong JF, Zhang YH, Zhu Y, Wu YJ. Synthesis, Characterization, and Crystal Structures of Three cis/trans Pyridine - Cyclopalladated Ferrocenylimine Complexes, and Their Catalysis in Suzuki Reactions. Aust J Chem 2007. [DOI: 10.1071/ch07014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Three new pyridine–cyclopalladated ferrocenylimine complexes 2a–c have been easily prepared and characterized by elemental analysis, ESI-MS, 1H NMR, and IR spectra. Their detailed structures are determined by single-crystal X-ray analysis. Palladacycle 2a is found to be a cis complex in the solid state, while 2b and 2c are trans complexes. These complexes were found to be efficient for the Suzuki reaction of aryl bromides with phenylboronic acid. Typically, using 0.2 mol% of 2c in the presence of 1.5 equivalents of K2CO3 as base in toluene at 100°C provided the coupled products in good to excellent yields.
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Brown RS, Neverov AA. Metal-catalyzed alcoholysis reactions of carboxylate and organophosphorus esters. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2007. [DOI: 10.1016/s0065-3160(07)42006-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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Neverov AA, Lu ZL, Maxwell CI, Mohamed MF, White CJ, Tsang JSW, Brown RS. Combination of a Dinuclear Zn2+ Complex and a Medium Effect Exerts a 1012-Fold Rate Enhancement of Cleavage of an RNA and DNA Model System. J Am Chem Soc 2006; 128:16398-405. [PMID: 17165797 DOI: 10.1021/ja0651714] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The catalytic ability of a dinuclear Zn2+ complex of 1,3-bis-N1-(1,5,9-triazacyclododecyl)propane (3) in promoting the cleavage of an RNA model, 2-hydroxypropyl-p-nitrophenyl phosphate (HPNPP, 1), and a DNA model, methyl p-nitrophenyl phosphate (MNPP, 4), was studied in methanol solution in the presence of added CH3O- at 25 degrees C. The di-Zn2+ complex (Zn2 :3), in the presence of 1 equiv of added methoxide, exhibits a second-order rate constant of (2.75 +/- 0.10) x 10(5) M(-1) s(-1) for the reaction with 1 at s(s)pH 9.5, this being 10(8)-fold larger than the k2 value for the CH3O- promoted reaction (kOCH3 = (2.56 +/- 0.16) x 10(-3) M(-1) s(-1)). The complex is also active toward the DNA model 4, exhibiting Michaelis-Menten kinetics with a KM and kmax of 0.37 +/- 0.07 mM and (4.1 +/- 0.3) x 10(-2) s(-1), respectively. Relative to the background reactions at s(s)pH 9.5, Zn2 :3 accelerates cleavage of each phosphate diester by a remarkable factor of 1012-fold. A kinetic scheme common to both substrates is discussed. The study shows that a simple model system comprising a dinuclear Zn2+ complex and a medium effect of the alcohol solvent achieves a catalytic reactivity that approaches enzymatic rates and is well beyond anything seen to date in water for the cleavage of these phosphate diesters.
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Affiliation(s)
- Alexei A Neverov
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada, K7L 3N6
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Ghosh KK, Sinha D, Satnami ML, Dubey DK, Shrivastava A, Palepu RM, Dafonte PR. Enhanced nucleophilic reactivity of hydroxamate ions in some novel micellar systems for the cleavage of Parathion. J Colloid Interface Sci 2006; 301:564-8. [PMID: 16797580 DOI: 10.1016/j.jcis.2006.05.061] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2006] [Revised: 05/19/2006] [Accepted: 05/23/2006] [Indexed: 11/28/2022]
Abstract
The reactivity of three alpha-nucleophiles, i.e. N-phenylbenzohydroxamate, benzohydroxamate and salicylhydroxamate ions towards cleavage of p-nitrophenyldiethyl phosphorothioate (Parathion) is considerably enhanced in the presence of cationic surfactant, i.e. cetyltrimethylammonium bromide. The esterolytic properties of N-phenylbenzohydroxamate ion for parathion have also been examined in two novel surfactants, viz. cetyltriphenylphosphonium bromide and cetyldimethyl ethanol ammonium bromide. The cetyldimethyl ethanol ammonium bromide is more reactive. The rate-surfactant profiles have been fitted with pseudophase model.
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Affiliation(s)
- Kallol K Ghosh
- School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur 492010, India.
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Gibson GTT, Mohamed MF, Neverov AA, Brown RS. Potentiometric Titration of Metal Ions in Ethanol. Inorg Chem 2006; 45:7891-902. [PMID: 16961382 DOI: 10.1021/ic060517x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The potentiometric titrations of Zn2+, Cu2+ and 12 Ln3+ metal ions were obtained in ethanol to determine the titration constants (defined as the at which the [-OEt]/[Mx+]t ratios are 0.5, 1.5, and 2.5) and in two cases (La3+ and Zn2+) a complete speciation diagram. Several simple monobasic acids and aminium ions were also titrated to test the validity of experimental titration measurements and to establish new constants in this medium that will be useful for the preparation of buffers and standard solutions. The dependence of the titration constants on the concentration and type of metal ion and specific counterion effects is discussed. In selected cases, the titration profiles were analyzed using a commercially available fitting program to obtain information about the species present in solution, including La3+ for which a dimer model is proposed. The fitting provides the microscopic values for deprotonation of one to four metal-bound ethanol molecules. Kinetics for the La3+-catalyzed ethanolysis of paraoxon as a function of are presented and analyzed in terms of La3+ speciation as determined by the analysis of potentiometric titration curves. The stability constants for the formation of Zn2+ and Cu2+ complexes with 1,5,9-triazacyclododecane as determined by potentiometric titration are presented.
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Affiliation(s)
- Graham T T Gibson
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6
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Lewis RE, Neverov AA, Stan Brown R. Mechanistic studies of La3+ and Zn2+-catalyzed methanolysis of O-ethyl O-aryl methylphosphonate esters. An effective solvolytic method for the catalytic destruction of phosphonate CW simulants. Org Biomol Chem 2005; 3:4082-8. [PMID: 16267587 DOI: 10.1039/b511550g] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The kinetics of methanolysis of six O-ethyl O-aryl methylphosphonates (6a-f) promoted by methoxide, La3+ and 1,5,9-triazacyclododecane complex of Zn2+(-OCH3) (5:Zn2+(-OCH3)) were studied as simulants for chemical warfare (CW) agents, and analyzed through the use of Brønsted plots. The beta(lg) values are, respectively, -0.76, -1.26 and -1.06, pointing to significant weakening of the P-OAr bond in the transition state. For the metal-catalyzed reactions the data are consistent with a concerted process where the P-OAr bond rupture has progressed to the extent of 84% in the La3+ reaction and ca. 70% in the Zn2+ catalyzed reaction. The catalysis afforded by the metal ions is remarkable, being about 10(6)-fold and 10(8)-fold for poor and good leaving groups, respectively, relative to the background reactions at pH 9.1. Solvent deuterium kinetic isotope studies for two of the substrates promoted by 5:Zn2+(-OCH3) give kH/kD = 1.0 +/- 0.1, consistent with a nucleophilic mechanism. A unified mechanism for the metal-catalyzed reactions is presented which involves pre-equilibrium coordination of the substrate to the metal ion followed by intramolecular delivery of a coordinated methoxide.
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Affiliation(s)
- Roxanne E Lewis
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6
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