New Synthetic Routes to Δ<sup>2</sup>-Pyrazolin-5-ones

Nye, M. J.; Tang, Wenxian

doi:10.1139/v73-049

Cited by 14 publications

(1 citation statement)

References 9 publications

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“…α-Hydroxyketones are versatile species in synthetic chemistry and have been used to prepare a variety of compounds via α-ketol rearrangement (eq ). , A possible involvement of the α-ketol rearrangement in biological reactions has also been a matter of controversy for many years …”

Section: Introductionmentioning

confidence: 99%

Mechanism of α-Ketol-Type Rearrangement of Benzoin Derivatives under Basic Conditions

et al. 2013

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The mechanism of base-catalyzed rearrangement of ring-substituted benzoins in aqueous methanol was examined by kinetic and product analyses. Substituent effects on the rate and equilibrium constants revealed that the kinetic process has a different electron demand compared to the equilibrium process. Reactions in deuterated solvents showed that the rate of H/D exchange of the α-hydrogen is similar to the overall rate toward the equilibrium state. A proton-inventory experiment using partially deuterated solvents showed a linear dependence of the rate on the deuterium fraction of the solvent, indicating that only one deuterium isotope effect contributes to the overall rate process. All these results point to a mechanism in which the rearrangement is initiated by the rate-determining α-hydrogen abstraction rather than a mechanism with initial hydroxyl hydrogen abstraction as in the general α-ketol rearrangement.

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