Base catalysed dehydration of α-alkoxybenzyl hydroperoxides: applications to zwitterion trapping reactions in ozonolysis

Ellam, R. M.; Padbury, J. M.

doi:10.1039/c39720001086

Cited by 16 publications

(3 citation statements)

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“…In the clocking experiments for compounds 9 – 14 shown in Table , carbonyl products were observed in chromatograms from reactions containing 12 – 14 but not in those containing 9 – 11 . Since 12 – 14 each contain basic nitrogen atoms, we surmised that a base-catalyzed dehydration mechanism may be responsible for the formation of these carbonyls . Indeed, when mixtures of the conjugated and nonconjugated hydroperoxides 15 and 16 were incubated with varying concentrations of different antioxidants under the same experimental conditions as used in the clocking experiments, the corresponding carbonyl-containing products were observed for those antioxidants containing basic nitrogen atoms.…”

Section: Discussionmentioning

confidence: 99%

“…Since 12−14 each contain basic nitrogen atoms, we surmised that a base-catalyzed dehydration mechanism may be responsible for the formation of these carbonyls. 29 Indeed, when mixtures of the conjugated and nonconjugated hydroperoxides 15 and 16 were incubated with varying concentrations of different antioxidants under the same experimental conditions as used in the clocking experiments, the corresponding carbonyl-containing products were observed for those antioxidants containing basic nitrogen atoms. Furthermore, when the solvent was changed from chlorobenzene to acetonitrile, the carbonyl-containing compounds were observed in solutions containing the same additive but in greater yield.…”

Section: Homolytic Cleavage Of the Weak O−o Bond In Conjunctionmentioning

confidence: 99%

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Peroxyesters As Precursors to Peroxyl Radical Clocks

Hanthorn

Pratt

2011

J. Org. Chem.

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The reactions of peroxyl radicals are at the center of the oxidative degradation of essentially all petroleum-derived hydrocarbons and biological lipids and consequently, the inhibition of these processes by radical-trapping antioxidants. Recently described peroxyl radical clocks offer a simple, convenient, and inexpensive method of determining rate constants for H-atom transfer reactions to peroxyl radicals, greatly enabling the kinetic and mechanistic characterization of compounds with antioxidant properties. We follow up our preliminary communication on the development of a methodology utilizing tert-butyl styrylperacetate as a precursor to a versatile peroxyl radical clock with the present paper, wherein we describe a novel naphthyl analogue, which provides for much improved product resolution for analysis, and provide the complete details associated with its development and application. Using this new precursor, and with consideration of the expanded set of reaction products, inhibition rate constants were measured for a variety of representative phenolic and diarylamine radical-trapping antioxidants. We also provide details for the use of this methodology for the determination of mechanistic information, such as kinetic solvent effects, Arrhenius parameters, and kinetic isotope effects.

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Section: Discussionmentioning

confidence: 99%

Section: Homolytic Cleavage Of the Weak O−o Bond In Conjunctionmentioning

confidence: 99%

Peroxyesters As Precursors to Peroxyl Radical Clocks

Hanthorn

Pratt

2011

J. Org. Chem.

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“…This reaction is simple and has been extensively studied. [8][9][10][11][12][13][14] Despite its simplicity this reaction is a good model for ozonolysis steps in the synthesis of important active pharmaceutical ingredients.…”

Section: Introductionmentioning

confidence: 99%

On-Line Analysis of a Continuous-Flow Ozonolysis Reaction Using Raman Spectroscopy

2007

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We describe the use of an on-line Raman analyzer to quantitatively track the levels of trans-stilbene, benzaldehyde, and alpha-methoxybenzyl hydroperoxide in a continuous flow ozonolysis reactor. Quantitative analysis is carried out using spectral stripping in order to overcome baseline artifacts inherent in simple peak area determinations and to incorporate prior knowledge into the analytical model. The performance of spectral stripping is compared to partial least squares (PLS) analysis. The effect of two process variables, feed flow rate and ozone concentration, are also explored. Finally, the benefit of utilizing an on-line technique is illustrated by demonstrating the bias introduced by sampling for off-line analysis.

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Ozone

Berglund

2001

Encyclopedia of Reagents for Organic Synthesis

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Base catalysed dehydration of α-alkoxybenzyl hydroperoxides: applications to zwitterion trapping reactions in ozonolysis

Abstract: a-Alkoxybenzyl hydroperoxides are converted rapidly and quantitatively a t room temperature into the corresponding alkyl benzoates by primary, secondary, and tertiary amines and by dimethyl sulphoxide.

Cited by 16 publications

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Peroxyesters As Precursors to Peroxyl Radical Clocks

Peroxyesters As Precursors to Peroxyl Radical Clocks

On-Line Analysis of a Continuous-Flow Ozonolysis Reaction Using Raman Spectroscopy

Ozone

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