What question did this study set out to answer?

To elucidate the reaction mechanism of molecular oxygen-induced oxidation and nucleophilic substitution in alkylpyrroles.

January 1, 1994Chemical Research in Toxicology

The mechanism of nucleophilic substitution of alkylpyrroles in the presence of oxygen

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Authors

VAVenkataraman AmarnathVanderbilt University Medical Center WVWilliam M. ValentineThe King's College KAKalyani AmarnathDuke University

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Implication

In vitro kinetic investigation uncovers oxygen-mediated substitution mechanisms in alkylpyrroles, suggesting an electron-transfer pathway via a reactive intermediate.

Key Points

To elucidate the reaction mechanism of molecular oxygen-induced oxidation and nucleophilic substitution in alkylpyrroles.
Monitored the oxidation and substitution reactions of alkylpyrroles (1a-d) in acetonitrile with excess molecular oxygen and added nucleophiles, including 2-mercaptoethanol.
Assessed reaction kinetics in the presence of radical inhibitors (BHT and catechol) and performed deuterium isotope labeling experiments using fully deuterated analogue 1aD.
Oxidation of alkylpyrroles produced dimers with intact aromatic rings, whereas adding 2-mercaptoethanol resulted in selective substitution at the 3-position with a first-order rate constant of (7.8 ± 1.2) × 10⁻⁷ s⁻¹.
Reaction rates remained unchanged upon the addition of radical inhibitors (BHT or catechol) and upon complete deuteration, though the final product exhibited deuterium loss at all sites.
The findings support a pathway initiated by complexation with triplet oxygen followed by a rate-limiting electron transfer step that generates a reactive pyrrolylmethyl intermediate.

Cite This Study

Amarnath et al. (1994) studied this question.

synapsesocial.com/papers/6a76589740780e633c81453a https://doi.org/10.1021/tx00037a008

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Implication

In vitro kinetic investigation uncovers oxygen-mediated substitution mechanisms in alkylpyrroles, suggesting an electron-transfer pathway via a reactive intermediate.

The mechanism of nucleophilic substitution of alkylpyrroles in the presence of oxygen

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Implication

Key Points

Cite This Study

The mechanism of nucleophilic substitution of alkylpyrroles in the presence of oxygen

Discussion

Member takes

Implication

Key Points

Cite This Study

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