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Laha JK, Kaur Hunjan M, Hegde S, Gupta A. Aroylation of Electron-Rich Pyrroles under Minisci Reaction Conditions. Org Lett 2020; 22:1442-1447. [DOI: 10.1021/acs.orglett.0c00041] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joydev K. Laha
- Department of Pharmaceutical Technology (Process Chemistry), National Institute of Pharmaceutical Education and Research, S. A. S. Nagar, Punjab 160062, India
| | - Mandeep Kaur Hunjan
- Department of Pharmaceutical Technology (Process Chemistry), National Institute of Pharmaceutical Education and Research, S. A. S. Nagar, Punjab 160062, India
| | - Shalakha Hegde
- Department of Pharmaceutical Technology (Process Chemistry), National Institute of Pharmaceutical Education and Research, S. A. S. Nagar, Punjab 160062, India
| | - Anjali Gupta
- Department of Pharmaceutical Technology (Process Chemistry), National Institute of Pharmaceutical Education and Research, S. A. S. Nagar, Punjab 160062, India
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Gargano EM, Mangiatordi GF, Weber I, Goebel C, Alberga D, Nicolotti O, Ruess W, Wierlacher S. Persulfate Reaction in a Hair-Bleaching Formula: Unveiling the Unconventional Reactivity of 1,13-Diamino-4,7,10-Trioxatridecane. ChemistryOpen 2018; 7:319-322. [PMID: 29744283 PMCID: PMC5931532 DOI: 10.1002/open.201800013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Indexed: 11/29/2022] Open
Abstract
The stability and unconventional reactivity of 1,13‐diamino‐4,7,10‐trioxatridecane in the presence of NH3, H2O2, and (NH4)2S2O8 are described. The ether‐diamine is an ingredient marketed to hair salons and consumers for so‐called “plex” services to compensate for hair damage during bleaching. The main reaction product identified is an unexpected azanyl ester derivative. This is considered relevant for the safety evaluation when used in cosmetic products. The mechanism of reaction was explored through DFT calculations. This study represents the first attempt to assess the stability of a plex active in an oxidative environment.
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Affiliation(s)
- Emanuele M Gargano
- Coty HFC Prestige Service (Germany) GmbH Berliner Allee 65 64295 Darmstadt Germany
| | - Giuseppe F Mangiatordi
- Dipartimento di Farmacia-Scienze del Farmaco Università di Bari "Aldo Moro" Via Orabona, 4 70126 Bari Italy
| | - Ingo Weber
- Coty HFC Prestige Service (Germany) GmbH Berliner Allee 65 64295 Darmstadt Germany
| | - Carsten Goebel
- Coty HFC Prestige Service (Germany) GmbH Berliner Allee 65 64295 Darmstadt Germany
| | - Domenico Alberga
- Dipartimento di Farmacia-Scienze del Farmaco Università di Bari "Aldo Moro" Via Orabona, 4 70126 Bari Italy
| | - Orazio Nicolotti
- Dipartimento di Farmacia-Scienze del Farmaco Università di Bari "Aldo Moro" Via Orabona, 4 70126 Bari Italy
| | - Wolfgang Ruess
- Coty HFC Prestige Service (Germany) GmbH Berliner Allee 65 64295 Darmstadt Germany
| | - Stefan Wierlacher
- Coty HFC Prestige Service (Germany) GmbH Berliner Allee 65 64295 Darmstadt Germany
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Mercado DF, Bracco LLB, Arques A, Gonzalez MC, Caregnato P. Reaction kinetics and mechanisms of organosilicon fungicide flusilazole with sulfate and hydroxyl radicals. CHEMOSPHERE 2018; 190:327-336. [PMID: 28992485 DOI: 10.1016/j.chemosphere.2017.09.134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/19/2017] [Accepted: 09/27/2017] [Indexed: 06/07/2023]
Abstract
Flusilazole is an organosilane fungicide used for treatments in agriculture and horticulture for control of diseases. The reaction kinetics and mechanism of flusilazole with sulfate and hydroxyl radicals were studied. The rate constant of the radicals with the fungicide were determined by laser flash photolysis of peroxodisulfate and hydrogen peroxide. The results were 2.0 × 109 s-1M-1 for the reaction of the fungicide with HO and 4.6 × 108 s-1 M-1 for the same reaction with SO4- radicals. The absorption spectra of organic intermediates detected by laser flash photolysis of S2O82- with flusilazole, were identified as α-aminoalkyl and siloxyl radicals and agree very well with those estimated employing the time-dependent density functional theory with explicit account for bulk solvent effects. In the continuous photolysis experiments, performed by photo-Fenton reaction of the fungicide, the main degradation products were: (bis(4-fluorophenyl)-hydroxy-methylsilane) and the non-toxic silicic acid, diethyl bis(trimethylsilyl) ester, in ten and twenty minutes of reaction, respectively.
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Affiliation(s)
- D Fabio Mercado
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900, La Plata, Argentina
| | - Larisa L B Bracco
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900, La Plata, Argentina
| | - Antonio Arques
- Grupo de Procesos de Oxidación Avanzada, Departamento de Ingeniería Textil y Papelera, Universitat Politècnica de València, Campus de Alcoy, Plaza Ferrandiz y Carbonell s/n, 03801, Alcoy, Spain
| | - Mónica C Gonzalez
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900, La Plata, Argentina
| | - Paula Caregnato
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900, La Plata, Argentina.
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Sunil Paul MM, Aravind UK, Pramod G, Saha A, Aravindakumar CT. Hydroxyl radical induced oxidation of theophylline in water: a kinetic and mechanistic study. Org Biomol Chem 2014; 12:5611-20. [PMID: 24957195 DOI: 10.1039/c4ob00102h] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxidative destruction and mineralization of emerging organic pollutants by hydroxyl radicals (˙OH) is a well established area of research. The possibility of generating hazardous by-products in the case of ˙OH reaction demands extensive investigations on the degradation mechanism. A combination of pulse radiolysis and steady state photolysis (H2O2/UV photolysis) followed by high resolution mass spectrometric (HRMS) analysis have been employed to explicate the kinetic and mechanistic features of the destruction of theophylline, a model pharmaceutical compound and an identified pollutant, by ˙OH in the present study. The oxidative destruction of this molecule, for intermediate product studies, was initially achieved by H2O2/UV photolysis. The transient absorption spectrum corresponding to the reaction of ˙OH with theophylline at pH 6, primarily caused by the generation of (T8-OH)˙, was characterised by an absorption band at 330 nm (k2 = (8.22 ± 0.03) × 10(9) dm(3) mol(-1) s(-1)). A significantly different spectrum (λmax: 340 nm) was observed at highly alkaline pH (10.2) due to the deprotonation of this radical (pKa∼ 10.0). Specific one electron oxidants such as sulphate radical anions (SO4˙(-)) and azide radicals (N3˙) produce the deprotonated form (T(-H)˙) of the radical cation (T˙(+)) of theophylline (pKa 3.1) with k2 values of (7.51 ± 0.04) × 10(9) dm(3) mol(-1) s(-1) and (7.61 ± 0.02) × 10(9) dm(3) mol(-1) s(-1) respectively. Conversely, oxide radicals (O˙(-)) react with theophylline via a hydrogen abstraction protocol with a rather slow k2 value of (1.95 ± 0.02) × 10(9) dm(3) mol(-1) s(-1). The transient spectral studies were complemented by the end product profile acquired by HRMS analysis. Various transformation products of theophylline induced by ˙OH were identified by this technique which include derivatives of uric acids (i, iv & v) and xanthines (ii, iii & vi). Further breakdown of the early formed product due to ˙OH attack leads to ring opened compounds (ix-xiv). The kinetic and mechanistic data furnished in the present study serve as a basic frame work for the construction of ˙OH induced water treatment systems as well as to understand the biological implications of compounds of this kind.
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Affiliation(s)
- M M Sunil Paul
- School of Environmental Sciences, Mahatma Gandhi University, Kottayam, India.
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Kumar A, Sevilla MD. π- vs σ-radical states of one-electron-oxidized DNA/RNA bases: a density functional theory study. J Phys Chem B 2013; 117:11623-32. [PMID: 24000793 DOI: 10.1021/jp407897n] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
As a result of their inherent planarity, DNA base radicals generated by one-electron oxidation/reduction or bond cleavage form π- or σ-radicals. While most DNA base systems form π-radicals, there are a number of nucleobase analogues such as one-electron-oxidized 6-azauraci1, 6-azacytosine, and 2-thiothymine or one-electron reduced 5-bromouracil that form more reactive σ-radicals. Elucidating the availability of these states within DNA, base radical electronic structure is important to the understanding of the reactivity of DNA base radicals in different environments. In this work, we address this question by the calculation of the relative energies of π- and σ-radical states in DNA/RNA bases and their analogues. We used density functional theory B3LYP/6-31++G** method to optimize the geometries of π- and σ-radicals in Cs symmetry (i.e., planar) in the gas phase and in solution using the polarized continuum model (PCM). The calculations predict that σ- and π-radical states in one-electron-oxidized bases of thymine, T(N3-H)(•), and uracil, U(N3-H)(•), are very close in energy; i.e., the π-radical is only ca. 4 kcal/mol more stable than the σ-radical. For the one-electron-oxidized radicals of cytosine, C(•+), C(N4-H)(•), adenine, A(•+), A(N6-H)(•), and guanine, G(•+), G(N2-H)(•), G(N1-H)(•), the π-radicals are ca. 16-41 kcal/mol more stable than their corresponding σ-radicals. Inclusion of solvent (PCM) is found to stabilize the π- over σ-radical of each of the systems. U(N3-H)(•) with three discrete water molecules in the gas phase is found to form a three-electron σ bond between the N3 atom of uracil and the O atom of a water molecule, but on inclusion of full solvation and discrete hydration, the π-radical remains most stable.
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Affiliation(s)
- Anil Kumar
- Department of Chemistry, Oakland University , Rochester, Michigan 48309, United States
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Barroso M, Delerue-Matos C, Oliveira M. Evaluation of the total antioxidant capacity of flavored water and electrochemical purine damage by sulfate radicals using a purine-based sensor. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2011.07.135] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Dell'Arciprete ML, Cobos CJ, Mártire DO, Furlong JP, Gonzalez MC. Reaction kinetics and mechanisms of neonicotinoidpesticides with sulfate radicals. NEW J CHEM 2011. [DOI: 10.1039/c0nj00726a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lehner AF, Horn J, Flesher JW. Mass spectrometric analysis of 7-sulfoxymethyl-12-methylbenz[a]anthracene and related electrophilic polycyclic aromatic hydrocarbon metabolites. JOURNAL OF MASS SPECTROMETRY : JMS 2004; 39:1366-1378. [PMID: 15532073 DOI: 10.1002/jms.730] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The Meso-region theory of polycyclic aromatic hydrocarbon (PAH) carcinogenesis predicts that the development of pronounced carcinogenicity depends on the introduction of a good leaving group on alkyl side-chains attached to the exceptionally reactive meso-anthracenic or L-region positions of PAHs. Thus, the first step in carcinogenesis by methylated PAHs such as 7,12-dimethylbenz[a]anthracene (DMBA) would be the hydroxylation of the L-region methyl groups, particularly the 7-methyl group. The second would be the formation of a metabolite, e.g. a sulfate ester, which is expected to be a good leaving group capable of generating a highly reactive benzylic carbocation. 7-Hydroxymethyl-12-methylbenz[a]anthracene (7-HMBA) is a metabolite of DMBA, and sulfation of 7-HMBA to a 7-sulfoxymethyl metabolite (7-SMBA) is a known Phase II metabolic process designed to facilitate excretion, but actually enabling more destructive side-reactions. These side-reactions occur with generation of an electrophilic 7-methylene carbonium ion, and/or by in vivo halide exchange to provide neutral side-products more capable of entering cells, especially those of DMBA target tissues. Electrospray ionization mass spectrometry (MS) enabled us to visualize 7-SMBA as an intact m/z 351 conjugate anion by negative mode, and as a released m/z 255 carbonium ion by positive mode. Upon prolonged refrigeration, 7-SMBA accumulated an m/z 383 photooxide, which appeared capable of re-evolving the starting material as visualized by tandem quadrupole MS, or MS/MS. The 7-SMBA carbonium ion provided interpretable fragments when studied by fragment ion MS/MS, including those representing the loss of up to several protons. Subtle differences in this property were encountered upon perturbing 7-SMBA, either by warming it at 37 degrees C for 2 h or by substituting the initial sulfoxy group with an iodo group. Side-reactions accounting for such proton losses are proposed, and are of interest whether they occur in the mass spectrometer, in solution or both; these proposals include acidity at the 12-methyl position and cyclization between the 12-methyl group and the adjacent C-1 position. It is also suggested that such side-reactions may comprise one route to relieving steric strain arising between the 12-methyl group and the angular benzo ring of 7-SMBA.
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MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene/analogs & derivatives
- 9,10-Dimethyl-1,2-benzanthracene/analysis
- 9,10-Dimethyl-1,2-benzanthracene/chemistry
- 9,10-Dimethyl-1,2-benzanthracene/metabolism
- Carcinogens/analysis
- Carcinogens/chemistry
- Carcinogens/metabolism
- Hydrocarbons, Halogenated/analysis
- Hydrocarbons, Halogenated/chemistry
- Hydrocarbons, Halogenated/metabolism
- Polycyclic Aromatic Hydrocarbons/analysis
- Polycyclic Aromatic Hydrocarbons/chemistry
- Polycyclic Aromatic Hydrocarbons/metabolism
- Spectrometry, Mass, Electrospray Ionization
- Xenobiotics/analysis
- Xenobiotics/chemistry
- Xenobiotics/metabolism
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Affiliation(s)
- Andreas F Lehner
- Department of Veterinary Science, University of Kentucky, Maxwell H. Gluck Equine Research Center, Lexington, Kentucky 40546, USA.
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