Aliphatische Thioketone

Mayer, Roland; Morgenstern, Johannes; Fabian, Jürgen

doi:10.1002/ange.19640760402

Cited by 69 publications

(6 citation statements)

References 79 publications

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“…By nuclear magnetic resonance spectrometry definite and quantitative data for keto-enol equilibria are available [142][143][144]. The prototropic tautomerism of thiones can also be detected by infrared spectrometry [145] and polarography [146]. The thiol form of 2(1H)-pyridine thione was predicted to be predominant in the gas phase not only by experimental methods (IR) but also by theoretical calculations [147].…”

Section: Ketones and Thioketonesmentioning

confidence: 99%

Tautomeric Equilibria Studies by Mass Spectrometry

Allegretti¹,

Schiavonni²,

Castro

et al. 2008

Nat Prec

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Tautomerism in organic chemistry has been extensively studied in condensed phase by spectrometric methods, mainly by IR and NMR techniques. Mass spectrometry studies start 40 years ago but just recently it has been recognized the importance of the mass spectral data for the study of tautomerism in the gas phase.Mass spectrometry can provide valuable information in regard to tautomeric equilibria when studying mass spectra among the members of different families of organic compounds.The relevance of the mass spectral data resides on several facts but there are two that are of key importance:1- Mass spectral fragmentation assignments should be tautomer specific since the corresponding abundances ratios are supposed to be correlated to the keto/enol contents.2- Ionization in the ion source is supposed to have no effect on the position of the equilibrium so that the results reflect the tautomers content in the gas phase previous to ionization.Some of the carbonylic compounds do not exhibit noticeable tautomerism so the fragment abundances assigned to the enol form is very low or not measurable. Since enolization is more noticeable in the case of thio-derivatives (which correlates adequately with the oxygenated analogues), the study of their mass spectra is an interesting choice to reach some degree of generalization. In addition, experimental findings are supported by semiempirical theoretical calculations, which probed to be adequate not only for supporting tendency correlations among the members of a compound family but also to calculate heats of tautomerization in gas phase.Reports using mass spectrometry for tautomerism are becoming less common. One of the reasons is that now it would appear that the interpretation of MS results is not as straightforward as it was once believed, even though in a recent review it was written that: “Mass spectrometry is the most informative and practical method for studying and identifying tautomers in the gas phase” [1]. In fact, mass spectrometry seems to be very informative for studying and identifying tautomers, because in this case external factors like solvents, intermolecular interactions, etc., can be excluded by transferring the tautomeric system into gas phase, where the process becomes truly unimolecular [1].This review covers the study of Tautomerism by Mass Spectrometry in the last four decades.

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Section: Ketones and Thioketonesmentioning

confidence: 99%

Tautomeric Equilibria Studies by Mass Spectrometry

Allegretti¹,

Schiavonni²,

Castro

et al. 2008

Nat Prec

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“…Their availability and stability depend on the substitution pattern . Although enolizable aliphatic thioketones are relatively unstable compounds , cycloaliphatic and aromatic thioketones, e.g., adamantanethione and thiobenzophenone, are isolable materials, which can be prepared from the corresponding ketones via O/S exchange and stored under inert gas atmosphere for a longer time. Moreover, “heavy analogues of thioketones” bearing SiS, GeS, etc.…”

Section: Introductionmentioning

confidence: 99%

Hetaryl Thioketones: Synthesis and Selected Reactions

Mlostoń

Urbaniak

Gebicki

et al. 2014

Heteroatom Chemistry

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A series of phenyl/hetaryl and bishetaryl thioketones have been prepared via oxygen/sulfur exchange of the corresponding ketones by treatment with Lawesson's reagent. The nonsymmetrical ketones were conveniently accessible via the reactions of lithiated furan, thiophene, and selenophene with N,N-dimethylbenzamide and hetarylcarboxamides, respectively, whereas the symmetrical ketones were obtained by treatment of ethyl N,N-dimethylcarbamate with 2 equiv of lithiated heterocycles. Under typical conditions, selected examples of the hetaryl thioketones were oxidized selectively to give thiocarbonyl S-oxides (sulfines). Reactions with diazomethane at -65°C yielded 1,3-dithiolanes in a regioselective manner and hetero-Diels-Alder reactions of 2-thienyl substituted thioketones with dimethyl acetylenedicarboxylate yielded the corresponding 7H-thieno [2,3-c]

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“…The prototropic tautomerism of thiones can also be detected by infrared spectrometry [15] and polarography [16]. The thiol form of 2(1H)-pyridine thione was predicted to be predominant in the gas phase, not only by experimental methods (IR) but also by theoretical calculations [17].…”

Section: Introductionmentioning

confidence: 99%

Enol and Enethiol Occurrence for Some Ketones and Thioketones. Mass Spectrometry and Theoretical Calculations

Allegretti

Schiavoni

Cortizo

et al. 2004

IJMS

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Abstract:The mass spectra of ketones can provide valuable information with regards to keto-enol equilibria occurring in the gas phase. Mass spectra of selected ketones and thioketones have been analysed and specific fragmentation assignments have been done to characterised and weigh co-existing keto and enol tautomers. Thioketones are of particular interest due to their tendency to shift the tautomeric equilibrium towards the enethiol form. The predictive value of this methodology is not only supported by the influence of these compound's nature and size of the substituent on these equilibria but also by the good correlation found between the selected fragments abundances ratio and semi-empirical calculation (AM1) of the corresponding heats of tautomerization.

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Aliphatische Thioketone

Abstract: Einige Autoren berichteten jedoch, bei der Umsetzung von Dipropylketon [3], Diisobutylketon [ 3 ] , Menthon [4], Fen-[ 3 ] A . J . Kretuw u.

Cited by 69 publications

References 79 publications

Tautomeric Equilibria Studies by Mass Spectrometry

Tautomeric Equilibria Studies by Mass Spectrometry

Hetaryl Thioketones: Synthesis and Selected Reactions

Enol and Enethiol Occurrence for Some Ketones and Thioketones. Mass Spectrometry and Theoretical Calculations

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