The Cupric-Ion Catalysis in the Bromination of Ethyl Acetoacetate.

Pedersen, Kai Julius; Kerkkonen, Heikki K.; Laaksonen, Terttu

doi:10.3891/acta.chem.scand.02-0252

Cited by 34 publications

(6 citation statements)

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“…To obtain the acidity constant for enol 10 we first note that acid dissociation constants of ends are not very sensitive to replacement of H by CH3 at the C-O carbon: pKE for vinyl alcohol is 10. 50,30 while that for 2-hydroxypropene is 10.94,26 a difference of 0.44 unit. The p£aK for (£)-2-phenylvinyl alcohol (12) is 9.31;24b hence we take p/faE for 10 to be 9.31 + 0.44 = 9.75.…”

Section: Discussionmentioning

confidence: 92%

2-Indanone and its enol. The effect of a conjugated phenyl group on enol and enolate stability

Keeffe¹,

Kresge²,

Yin³

1988

J. Am. Chem. Soc.

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Section: Discussionmentioning

confidence: 92%

2-Indanone and its enol. The effect of a conjugated phenyl group on enol and enolate stability

Keeffe¹,

Kresge²,

Yin³

1988

J. Am. Chem. Soc.

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“…The reaction in the mole ratio of 1 : 1.5 is represented by (4) Similarly the reaction in the mole ratio of 1 : 2 is written as (5) In this case the product 3, 3-dibromoacetylacetone has no active hydrogen to react with copper(II) bromide, and thus the latter remains unchanged even after standing a long time in the product solution.…”

Section: Discussionmentioning

confidence: 99%

“…Pedersen investigated the bromination of ethyl acetoacetate in aqueous solution and found that the first of the two consecutive reactions was catalyzed by copper(II) 4) and other divalent metal ions.5) The intermediate metal chelate of the keto-form of the ester was assumed to transfer a proton to the catalyst base more easily than the substrate itself does. However, details of the succeeding reaction, that is, the bromination of the normal metal enolate ester are not yet clear.…”

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confidence: 99%

Reaction of Bis(acetylacetonato)copper(II) with Bromine

Nakamura¹,

Kawaguchi²

1965

Bulletin of the Chemical Society of Japan

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“…by a laborious process of curve fitting. In a later study at 18 °C (Pedersen 1948) he measured the overall rate by observing the disappearance of bromine by the ' deadstop' technique and analysed the results by the method of Swain (1944), again obtaining k2/kx = 12. Bell et a l .…”

Section: Ethyl A-bromoacetoamentioning

confidence: 99%

Kinetic hydrogen isotope effects in the ionization of some ketonic substances

Bell

Crooks

1965

Proc. R. Soc. Lond. A

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The kinetic hydrogen isotope effect has been measured for the water-catalysed bromination of acetylacetone, monobromoacetylacetone, ethyl acetoacetate, ethyl α-bromoacetoacetate, ethyl α-methylacetoacetate, ethyl malonate, ethyl monobromomalonate, and methyl methyl - malonate and for the bromination of ethyl a-methylacetoacetate catalysed by six basic anions. All these reactions are of zero order with respect to bromine, so that the process studied is the rate of transfer of a proton or deuteron from the organic molecule to the catalyst. For ethyl a-methylacetoacetate there is a correlation between the basic strength of the catalyst, the rate of proton transfer, and the magnitude of the isotope effect. Various possible explanations are considered for the variation in isotope effect, and it is concluded that current interpretations in terms of a three-centre model of the transition state are inadequate. The isotope effect also varies considerably with the nature of the organic molecule, but is not in general related to its reactivity. There is, however, a correlation between the magnitude of the isotope effect and the exponent β of the Brönsted relation between basic strength and catalytic power, suggesting that both quantities depend on the position of the proton in the transition state.

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The Cupric-Ion Catalysis in the Bromination of Ethyl Acetoacetate.

Cited by 34 publications

References 0 publications

2-Indanone and its enol. The effect of a conjugated phenyl group on enol and enolate stability

2-Indanone and its enol. The effect of a conjugated phenyl group on enol and enolate stability

Reaction of Bis(acetylacetonato)copper(II) with Bromine

Kinetic hydrogen isotope effects in the ionization of some ketonic substances

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