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Mahmood A, Teixeira ES, Longo RL. Understanding the Reactivity and Regioselectivity of Methylation of Nitronates [R(1)R(2)CNO2](-) by CH3I in the Gas Phase. J Org Chem 2015; 80:8198-205. [PMID: 26181145 DOI: 10.1021/acs.joc.5b01273] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methylation of [R(1)R(2)CNO2](-), where R(1) = R(2) = H (1), R(1) = CH3 and R(2) = H (2), R(1) = R(2) = CH3 (3), and R(1) + R(2) = c-(CH2)2 (4), by CH3I was studied by an ab initio MP2/CBS method, RRKM theory, and kinetic simulations. Contrary to a previous proposal for the reaction mechanism, C-methylation is the preferred pathway of thermodynamics and kinetics. This is corroborated by the agreement between the calculated and experimental reactivity trend 4 ≫ 3 > 2 > 1. The regioselectivity toward C-alkylation is explained by the much larger exothermicity of this reaction channel compared to that of O-alkylation. The increase in reactivity with an increase in the crowdedness of the central carbon atom is explained by differences in sp(3) character at this atom and the decrease in the vibrational frequency associated with pyramidalization around this carbon atom.
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Affiliation(s)
- Ayyaz Mahmood
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE 50740-560, Brazil
| | - Erico Souza Teixeira
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE 50740-560, Brazil
| | - Ricardo L Longo
- Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, Recife, PE 50740-560, Brazil
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Kafle A, Coy SL, Wong BM, Fornace AJ, Glick JJ, Vouros P. Understanding gas phase modifier interactions in rapid analysis by differential mobility-tandem mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:1098-113. [PMID: 24452298 PMCID: PMC4057941 DOI: 10.1007/s13361-013-0808-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 12/09/2013] [Indexed: 05/04/2023]
Abstract
A systematic study involving the use and optimization of gas-phase modifiers in quantitative differential mobility-mass spectrometry (DMS-MS) analysis is presented using nucleoside-adduct biomarkers of DNA damage as an important reference point for analysis in complex matrices. Commonly used polar protic and polar aprotic modifiers have been screened for use against two deoxyguanosine adducts of DNA: N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-4-ABP) and N-(deoxyguanosin-8-y1)-2-amino-l-methyl-6-phenylimidazo[4,5-b]pyridine (dG-C8-PhIP). Particular attention was paid to compensation voltage (CoV) shifts, peak shapes, and product ion signal intensities while optimizing the DMS-MS conditions. The optimized parameters were then applied to rapid quantitation of the DNA adducts in calf thymus DNA. After a protein precipitation step, adduct levels corresponding to less than one modification in 10(6) normal DNA bases were detected using the DMS-MS platform. Based on DMS fundamentals and ab initio thermochemical results, we interpret the complexity of DMS modifier responses in terms of thermal activation and the development of solvent shells. At very high bulk gas temperature, modifier dipole moment may be the most important factor in cluster formation and cluster geometry, but at lower temperatures, multi-neutral clusters are important and less predictable. This work provides a useful protocol for targeted DNA adduct quantitation and a basis for future work on DMS modifier effects.
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Affiliation(s)
- Amol Kafle
- Department of Chemistry and Chemical Biology and Barnett Institute, Northeastern University, Boston, MA
| | | | - Bryan M. Wong
- Department of Chemistry and Department of Materials Science & Engineering, Drexel University, Philadelphia, PA 19104
| | - Albert J. Fornace
- Georgetown University, Department of Biochemistry & Molecular & Cell Biology, Washington, DC 20057 USA, and King Abdulaziz Univ, Center of Excellence in Genomic Medical Research, Jeddah 21413, Saudi Arabia
| | - James J. Glick
- Department of Chemistry and Chemical Biology and Barnett Institute, Northeastern University, Boston, MA
| | - Paul Vouros
- Corresponding authors: (617)373-2840; (508)808-8227
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Belikov AE, Smith MA. Low-Temperature Kinetics of the Charge- and Atom-Transfer Reactions (Br+, HBr+ [2Πi, v+], DBr+ [2Πi , v+]) + (HBr, DBr) → (HBr+, DBr+, H2Br+, D2Br+, HDBr+). J Phys Chem A 2004. [DOI: 10.1021/jp031254k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andrey E. Belikov
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
| | - Mark A. Smith
- Department of Chemistry, University of Arizona, Tucson, Arizona 85721
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Viggiano AA, Seeley JV, Mundis PL, Williamson JS, Morris RA. Rate Constants for the Reactions of XO3-(H2O)n (X = C, HC, and N) and NO3-(HNO3)n with H2SO4: Implications for Atmospheric Detection of H2SO4. J Phys Chem A 1997. [DOI: 10.1021/jp971768h] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A. A. Viggiano
- Phillips Laboratory, Geophysics Directorate (GPSC), 29 Randolph Road, Hanscom AFB, Massachusetts 01731-3010
| | - John V. Seeley
- Phillips Laboratory, Geophysics Directorate (GPSC), 29 Randolph Road, Hanscom AFB, Massachusetts 01731-3010
| | - Paul L. Mundis
- Phillips Laboratory, Geophysics Directorate (GPSC), 29 Randolph Road, Hanscom AFB, Massachusetts 01731-3010
| | - John S. Williamson
- Phillips Laboratory, Geophysics Directorate (GPSC), 29 Randolph Road, Hanscom AFB, Massachusetts 01731-3010
| | - Robert A. Morris
- Phillips Laboratory, Geophysics Directorate (GPSC), 29 Randolph Road, Hanscom AFB, Massachusetts 01731-3010
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Wei J, Meng Q, Su T. Trajectory studies of the reaction F −+HCl→HF+Cl −. I. Reaction rate constant. J Chem Phys 1995. [DOI: 10.1063/1.469141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Su T. Parametrization of kinetic energy dependences of ion–polar molecule collision rate constants by trajectory calculations. J Chem Phys 1994. [DOI: 10.1063/1.466255] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Transition State Theory of Fast Charge-Transfer Reactions in Ion–Dipole and Ion–Quadrupole Systems. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/b978-1-55938-553-4.50010-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Hase WL, Darling CL, Zhu L. Dynamics of ion–molecule recombination. V. A study of energy transfer pathways. J Chem Phys 1992. [DOI: 10.1063/1.462333] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Viggiano AA, Morris RA, Dale F, Paulson JF, Giles K, Smith D, Su T. Kinetic energy, temperature, and derived rotational temperature dependences for the reactions of Kr+(2P3/2) and Ar+ with HCl. J Chem Phys 1990. [DOI: 10.1063/1.459178] [Citation(s) in RCA: 176] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Morris RA, Viggiano AA, Paulson JF, Su T. Temperature and kinetic energy dependences of the rate constant for the reaction 22Ne++20Ne. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1990; 41:5943-5947. [PMID: 9902995 DOI: 10.1103/physreva.41.5943] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Turulski J, Niedzielski J. How much do the ion-dipole capture rate constants obtained by transition state theory differ from those given by trajectory calculations? Mol Phys 1989. [DOI: 10.1080/00268978900101011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Affiliation(s)
- W. Stiller
- Zentralinstitut für Isotopen- und Strahlungsforschung der Akademie der Wissenschaften der DDR, Permoserstr. 15, Leipzig, 7050, German Democratic Republic
| | - J. Turulski
- Chemistry Department, Agricultural and Teachers University, Siedlce, Poland
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Kern K, Schlier C. Orbiting trajectories and the adiabatic approximation to the capture cross section. ACTA ACUST UNITED AC 1986. [DOI: 10.1007/bf01431182] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Hu S, Su T. Trajectory calculations of the effect of the induced dipole–induced dipole potential on ion–polar molecule collision rate constants. J Chem Phys 1986. [DOI: 10.1063/1.451023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Marquette J, Rowe B, Dupeyrat G, Poissant G, Rebrion C. Ion—polar-molecule reactions: A CRESU study of He+, C+, N+ + H2O, NH3 at 27, 68 and 163 K. Chem Phys Lett 1985. [DOI: 10.1016/0009-2614(85)87241-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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