The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Fumihiko Jitsunari - One of the best experts on this subject based on the ideXlab platform.
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investigation of indoor air pollution by chlorpyrifos determination of chlorpyrifos in indoor air and 3 5 6 trichloro 2 Pyridinol in residents urine as an exposure index
Environmental Health and Preventive Medicine, 2003Co-Authors: Fumiyuki Asakawa, Shigeru Suna, Tomohiro Hirao, Tomonori Karita, Ichiro Fukunaga, Fumihiko JitsunariAbstract:Objects We carried out an investigation to clarify the real state of indoor air pollution by chlorpyrifos (termiticide) and exposure to chlorpyrifos of residents by measuring its urinary metabolite 3,5,6-trichloro-2-Pyridinol (TCP) as an exposure index, such as biological monitoring.
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Investigation of indoor air pollution by chlorpyrifos: Determination of chlorpyrifos in indoor air and 3,5,6-trichloro-2-Pyridinol in residents’ urine as an exposure index
Environmental Health and Preventive Medicine, 2003Co-Authors: Fumiyuki Asakawa, Shigeru Suna, Tomohiro Hirao, Tomonori Karita, Ichiro Fukunaga, Fumihiko JitsunariAbstract:Objects We carried out an investigation to clarify the real state of indoor air pollution by chlorpyrifos (termiticide) and exposure to chlorpyrifos of residents by measuring its urinary metabolite 3,5,6-trichloro-2-Pyridinol (TCP) as an exposure index, such as biological monitoring. Methods The investigation was conducted in 43 individual houses with termiticide application (whether the termiticide was chlorpyrifos is uncertain) and 3 control houses without any termiticide application in Kagawa, Japan. Urine samples were collected from 46 healthy adult residents of the aforementioned houses. Results Chlorpyrifos in indoor air in the control houses was not detected (ND
Luca Valgimigli - One of the best experts on this subject based on the ideXlab platform.
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3-Pyridinols and 5-pyrimidinols: Tailor-made for use in synergistic radical-trapping co-antioxidant systems
Beilstein Journal of Organic Chemistry, 2013Co-Authors: Luca Valgimigli, Johan Brinkhorst, Daniele Bartolomei, Riccardo Amorati, Evan A. Haidasz, Jason J. Hanthorn, Susheel J. Nara, Derek A. PrattAbstract:The incorporation of nitrogen atoms into the aromatic ring of phenolic compounds has enabled the development of some of the most potent radical-trapping antioxidants ever reported. These compounds, 3-Pyridinols and 5-pyrimidinols, have stronger O–H bonds than equivalently substituted phenols, but possess similar reactivities toward autoxidation chain-carrying peroxyl radicals. These attributes suggest that 3-Pyridinols and 5-pyrimidinols will be particularly effectiveco-antioxidants when used in combination with more common, but less reactive, phenolic antioxidants such as 2,6-di-tert-butyl-4-methylphenol (BHT), which we demonstrate herein. The antioxidants function in a synergistic manner to inhibit autoxidation; taking advantage of the higher reactivity of the 3-Pyridinols/5-pyrimidinols to trap peroxyl radicals and using the less reactive phenols to regenerate them from their corresponding aryloxyl radicals. The present investigations were carried out in chlorobenzene and acetonitrile in order to provide some insight into the medium dependence of the synergism and the results, considered with some from our earlier work, prompt a revision of the H-bonding basicity value of acetonitrile to β2H of 0.39. Overall, the thermodynamic and kinetic data presented here enable the design of co-antioxidant systems comprising lower loadings of the more expensive 3-Pyridinol/5-pyrimidinol antioxidants and higher loadings of the less expensive phenolic antioxidants, but which are equally efficacious as the 3-Pyridinol/5-pyrimidinol antioxidants alone at higher loadings.
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catalytic chain breaking Pyridinol antioxidants
Journal of Organic Chemistry, 2010Co-Authors: Sangit Kumar, Gian Franco Pedulli, Riccardo Amorati, Henrik Johansson, Takahiro Kanda, Lars Engman, Thomas J J Muller, Helena Bergenudd, Mats Jonsson, Luca ValgimigliAbstract:The synthesis of 3-Pyridinols carrying alkyltelluro, alkylseleno, and alkylthio groups is described together with a detailed kinetic, thermodynamic, and mechanistic study of their antioxidant activity. When assayed for their capacity to inhibit azo-initiated peroxidation of linoleic acid in a water/chlorobenzene two-phase system, tellurium-containing 3-Pyridinols were readily regenerable by N-acetylcysteine contained in the aqueous phase. The best inhibitors quenched peroxyl radicals more efficiently than α-tocopherol, and the duration of inhibition was limited only by the availability of the thiol reducing agent. In homogeneous phase, inhibition of styrene autoxidation absolute rate constants kinh for quenching of peroxyl radical were as large as 1 × 107 M−1 s−1, thus outperforming the best phenolic antioxidants including α-tocopherol. Tellurium-containing 3-Pyridinols could be quantitatively regenerated in homogeneous phase by N-tert-butoxycarbonyl cysteine methyl ester, a lipid-soluble analogue of N-ac...
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catalytic chain breaking Pyridinol antioxidants
Organic Letters, 2008Co-Authors: Sangit Kumar, Gian Franco Pedulli, Henrik Johansson, Takahiro Kanda, Lars Engman, Thomas J J Muller, Mats Jonsson, Silvia Petrucci, Luca ValgimigliAbstract:When assayed for their capacity to inhibit azo-initiated peroxidation of linoleic acid in a water/chlorobenzene two-phase system, tellurium-containing 3-Pyridinols were readily regenerable by N-ace ...
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Synthesis and reactivity of some 6-substituted-2,4-dimethyl-3-Pyridinols, a novel class of chain-breaking antioxidants.
Journal of Organic Chemistry, 2004Co-Authors: Maikel Wijtmans, Derek A. Pratt, Johan Brinkhorst, Remigiusz A. Serwa, Luca Valgimigli, Gian Franco Pedulli, Ned A. PorterAbstract:The synthesis and study of a series of 6-substituted-2,4-dimethyl-3-Pyridinols having interesting antioxidant properties is reported. The general synthetic strategy leading to the compounds involved a low-temperature aryl bromide-to-alcohol conversion as the last step. 2,4-Dimethyl-3-Pyridinol (1a), 2,4,6-trimethyl-3-Pyridinol (1b), and 2,4-dimethyl-6-(dimethylamino)-3-Pyridinol (1d) were thus prepared from the corresponding 3-bromopyridine precursor. The methoxy derivative 2,4-dimethyl-6-(methoxy)-3-Pyridinol (1c) was also prepared by an alternate route via a Baeyer−Villiger reaction on the substituted benzaldehyde precursor. Novel bicyclic Pyridinols 2 and 3 required prior construction of the ring structure. Thus, 2 was prepared by the use of a 6-step intramolecular Friedel−Crafts strategy, and 3 required an 11-step sequence with a thermolytic intramolecular inverse-demand Diels−Alder reaction between a pyrimidine ring and an alkyne as the key step. Basicities of the Pyridinols approached physiological ...
Fumiyuki Asakawa - One of the best experts on this subject based on the ideXlab platform.
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investigation of indoor air pollution by chlorpyrifos determination of chlorpyrifos in indoor air and 3 5 6 trichloro 2 Pyridinol in residents urine as an exposure index
Environmental Health and Preventive Medicine, 2003Co-Authors: Fumiyuki Asakawa, Shigeru Suna, Tomohiro Hirao, Tomonori Karita, Ichiro Fukunaga, Fumihiko JitsunariAbstract:Objects We carried out an investigation to clarify the real state of indoor air pollution by chlorpyrifos (termiticide) and exposure to chlorpyrifos of residents by measuring its urinary metabolite 3,5,6-trichloro-2-Pyridinol (TCP) as an exposure index, such as biological monitoring.
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Investigation of indoor air pollution by chlorpyrifos: Determination of chlorpyrifos in indoor air and 3,5,6-trichloro-2-Pyridinol in residents’ urine as an exposure index
Environmental Health and Preventive Medicine, 2003Co-Authors: Fumiyuki Asakawa, Shigeru Suna, Tomohiro Hirao, Tomonori Karita, Ichiro Fukunaga, Fumihiko JitsunariAbstract:Objects We carried out an investigation to clarify the real state of indoor air pollution by chlorpyrifos (termiticide) and exposure to chlorpyrifos of residents by measuring its urinary metabolite 3,5,6-trichloro-2-Pyridinol (TCP) as an exposure index, such as biological monitoring. Methods The investigation was conducted in 43 individual houses with termiticide application (whether the termiticide was chlorpyrifos is uncertain) and 3 control houses without any termiticide application in Kagawa, Japan. Urine samples were collected from 46 healthy adult residents of the aforementioned houses. Results Chlorpyrifos in indoor air in the control houses was not detected (ND
Howard Alper - One of the best experts on this subject based on the ideXlab platform.
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domino ring opening carboxamidation reactions of n tosyl aziridines and 2 halophenols Pyridinol efficient synthesis of 1 4 benzo and pyrido oxazepinones
Organic Letters, 2010Co-Authors: Gagan Chouhan, Howard AlperAbstract:A domino process is described for the synthesis of 1,4-benzo- and pyrido-oxazepinones by one-pot sequential ring-opening/carboxamidation reactions of various N-tosylaziridines with a range of 2-halophenols/Pyridinol under phase-transfer catalysis.
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Domino Ring-Opening/Carboxamidation Reactions of N-Tosyl Aziridines and 2-Halophenols/Pyridinol: Efficient Synthesis of 1,4-Benzo- and Pyrido-oxazepinones
Organic Letters, 2010Co-Authors: Gagan Chouhan, Howard AlperAbstract:A domino process is described for the synthesis of 1,4-benzo- and pyrido-oxazepinones by one-pot sequential ring-opening/carboxamidation reactions of various N-tosylaziridines with a range of 2-halophenols/Pyridinol under phase-transfer catalysis.
Sangit Kumar - One of the best experts on this subject based on the ideXlab platform.
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catalytic chain breaking Pyridinol antioxidants
Journal of Organic Chemistry, 2010Co-Authors: Sangit Kumar, Gian Franco Pedulli, Riccardo Amorati, Henrik Johansson, Takahiro Kanda, Lars Engman, Thomas J J Muller, Helena Bergenudd, Mats Jonsson, Luca ValgimigliAbstract:The synthesis of 3-Pyridinols carrying alkyltelluro, alkylseleno, and alkylthio groups is described together with a detailed kinetic, thermodynamic, and mechanistic study of their antioxidant activity. When assayed for their capacity to inhibit azo-initiated peroxidation of linoleic acid in a water/chlorobenzene two-phase system, tellurium-containing 3-Pyridinols were readily regenerable by N-acetylcysteine contained in the aqueous phase. The best inhibitors quenched peroxyl radicals more efficiently than α-tocopherol, and the duration of inhibition was limited only by the availability of the thiol reducing agent. In homogeneous phase, inhibition of styrene autoxidation absolute rate constants kinh for quenching of peroxyl radical were as large as 1 × 107 M−1 s−1, thus outperforming the best phenolic antioxidants including α-tocopherol. Tellurium-containing 3-Pyridinols could be quantitatively regenerated in homogeneous phase by N-tert-butoxycarbonyl cysteine methyl ester, a lipid-soluble analogue of N-ac...
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catalytic chain breaking Pyridinol antioxidants
Organic Letters, 2008Co-Authors: Sangit Kumar, Gian Franco Pedulli, Henrik Johansson, Takahiro Kanda, Lars Engman, Thomas J J Muller, Mats Jonsson, Silvia Petrucci, Luca ValgimigliAbstract:When assayed for their capacity to inhibit azo-initiated peroxidation of linoleic acid in a water/chlorobenzene two-phase system, tellurium-containing 3-Pyridinols were readily regenerable by N-ace ...
