Tautomerism of azine derivatives. 11.14N-NMR and17O-NMR investigation of intrachelate tautomerism of acylmethylpyridines

Lapachev, V. V.; Stekhova, S. A.; Mainagashev, I. Ya.; Fedotov, M. A.; Khall, V. E.; Mamaev, V. P.

doi:10.1007/bf00575245

Cited by 2 publications

(3 citation statements)

References 17 publications

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“…16 It is the only tautomer present in the crystal. 17 The amount of the E form was found to increase at higher temperatures. 26 A chloroform solution of 2-(4-nitrophenacyl)pyridine contains 93 and 7% of the forms O and K, respectively.…”

Section: Introductionmentioning

confidence: 91%

“…β-diketones, β-ketoesters and β-diesters, 3 and β-enaminones, e.g. β-aminoacroleins, 4-7 N-salicylideneanilines 7-12 and 2-phenacylpyridines, [13][14][15][16][17][18] are in equilibrium with two other tautomeric forms. The enaminone form prevails in solutions of various β-aminoacroleins in different solvents at different temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Substituent and temperature controlled tautomerism of 2-phenacylpyridine: the hydrogen bond as a configurational lock of (Z )-2-(2-hydroxy-2-phenylvinyl)pyridine

Kolehmainen

Ośmiałowski²,

Nissinen

et al. 2000

J. Chem. Soc., Perkin Trans. 2

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2-Phenacylpyridines substituted in the benzene ring are in equilibrium with (Z)-2-(2-hydroxy-2-phenylvinyl)pyridines when dissolved in chloroform. The substituent affects significantly the tautomeric equilibrium [the amount of the enolimine form stabilized by the intramolecular hydrogen bond is 1 and 92% for R = p-N(CH 2 ) 4 and p-NO 2 , respectively]. The negative logarithm of the tautomeric equilibrium constant, K T , is linearly dependent on the Hammett σ substituent constants. The dependence of K T vs. temperature is exponential in character: the more electronwithdrawing is the substituent, the more distinct is the influence of temperature. Unexpectedly, the tautomer present in the crystalline state is not the same for all compounds studied (it is the ketimine one for those carrying strong electron-donor groups). Among the different ab initio methods used to calculate the enthalpy of the proton transfer in chloroform solution, MP2/6-31G** gives the best results.

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Substituent and temperature controlled tautomerism of 2-phenacylpyridine: the hydrogen bond as a configurational lock of (Z )-2-(2-hydroxy-2-phenylvinyl)pyridine

Kolehmainen

Ośmiałowski²,

Nissinen

et al. 2000

J. Chem. Soc., Perkin Trans. 2

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“…The reaction of 2-ketomethylquinolines with bromine in chloroform was studied in an attempt to effect x-bromination, 21 10 but this was only successful in one instance, thus 9 was obtained from 20, R = Bu', in 82% yield. Similar bromination in glacial acetic acid gave compound 1.…”

mentioning

confidence: 99%

Tautomerism in ketomethylquinolines. Part 2. Further results on 2-ketomethylquinolines

Greenhill¹,

Loghmani-Khouzani²,

Maitland³

1991

J. Chem. Soc., Perkin Trans. 1

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Tautomerism of azine derivatives. 11.14N-NMR and17O-NMR investigation of intrachelate tautomerism of acylmethylpyridines

Cited by 2 publications

References 17 publications

Substituent and temperature controlled tautomerism of 2-phenacylpyridine: the hydrogen bond as a configurational lock of (Z )-2-(2-hydroxy-2-phenylvinyl)pyridine

Substituent and temperature controlled tautomerism of 2-phenacylpyridine: the hydrogen bond as a configurational lock of (Z )-2-(2-hydroxy-2-phenylvinyl)pyridine

Tautomerism in ketomethylquinolines. Part 2. Further results on 2-ketomethylquinolines

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