New derivatives of trifluoroacetyl acetaldehyde and trifluoroaldol

Kondratov, Ivan S.; Gerus, Igor I.; Kacharov, Aleksey D.; Gorbunova, M. G.; Kukhar, V. P.; Fröhlich, Roland

doi:10.1016/j.jfluchem.2004.12.006

Cited by 15 publications

(7 citation statements)

References 17 publications

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“…14 The minor open-chain forms 5a, 7a and 9a constituted about 15% together. 15 The part of acyclic forms 5a, 7a and 9a increased when a more polar solvent such as THF-d 8 was added to the CDCl 3 solution. Thus, 19 F NMR spectra in mixtures of CDCl 3 /THF-d 8 (10 : 1, 2 : 1, 1 : 1) indicated ratios of 8a/(5a + 7a + 9a) of 77 : 23, 58 : 42, 51 : 49, respectively.…”

Section: Resultsmentioning

confidence: 99%

Reactions of β-alkoxyvinyl polyfluoroalkyl ketones with ethyl isocyanoacetate and its use for the synthesis of new polyfluoroalkyl pyrroles and pyrrolidines

Kondratov¹,

Dolovanyuk²,

Tolmachova³

et al. 2012

Org. Biomol. Chem.

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The hitherto unreported reactions of β-alkoxyvinyl polyfluoroalkyl ketones with ethyl isocyanoacetate and equimolar amounts of potassium-tert-butoxide proceeded mainly in the β-position of the α,β-unsaturated ketones in cases of α-nonsubstituted 1a–e and α-methyl substituted ketones 1g–j. Other α- or β-substituted ketones 1f,k–o gave mainly products 4 of initial attack at the carbonyl carbon. Depending on the solvent, the major products of β-attack do exist in different tautomeric forms. Generally the openchain enol tautomers 5 predominate in the polar DMSO-d(6), while the cyclic γ-hemiaminals 8 are the major tautomers in the less polar CDCl(3). Acid treatment of the latter compounds 8 led to the hitherto unknown ethyl 5-polyfluoroalkyl-pyrrole-2-carboxylates 11 by elimination of formic acid. Catalytic hydrogenation of pyrrole 11a was used for the synthesis of earlier unknown 5-trifluoromethyl proline 16.

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Section: Resultsmentioning

confidence: 99%

Reactions of β-alkoxyvinyl polyfluoroalkyl ketones with ethyl isocyanoacetate and its use for the synthesis of new polyfluoroalkyl pyrroles and pyrrolidines

Kondratov¹,

Dolovanyuk²,

Tolmachova³

et al. 2012

Org. Biomol. Chem.

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“…This effect is smaller than the resonance deshielding observed for the trifluoroacetic acid derivatives (series 5-9), with chemical shifts for compound series 10 differing by only ∼1 ppm. 17 Even when Y = Ph, the additional conjugation afforded by the benzene ring does not serve to deshield the −CF 3 group to any greater extent (δ = −78.1 ppm). Solvent and concentration effects on the 19 F NMR chemical shifts would be minimal for this series of compounds.…”

Section: Discussion and Analysis Of Chemical Shift Variations For Tfamentioning

confidence: 99%

19-Fluorine nuclear magnetic resonance chemical shift variability in trifluoroacetyl species

Sloop¹

2013

ROC

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This review examines the variability of chemical shifts observed in 19-fluorine ( 19 F) nuclear magnetic resonance spectra for the trifluoroacetyl (TFA) functional group. The range of 19 F chemical shifts reported spectra for the TFA group varies generally from −85 to −67 ppm relative to CFCl 3 . The literature revealed several factors that impact chemical shifts of the TFA moiety − substrate topology, electronic environment, solvent polarity, and concentration effects. Often these effects conspire to cause deshielding of the TFA group by up to 15 ppm. These factors will be examined for a series of TFA-functionalized acyclic, cyclic, aromatic, and heterocyclic molecules.

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“…All solvents and liquid reagents were distilled before use. Starting enones 5a, 11a 5b, 11c chiral enones 5c-e, 14 and ketoacetal 9 14 were prepared according to literature procedures.…”

Section: Generalmentioning

confidence: 99%