Gas chromatography–mass spectrometry of the stereoisomers of heterocyclic compounds. Part 2a.1 Perhydroxanthenes

Bobyleva, M. S.; Kulikov, N. S.

doi:10.1039/a706142k

Cited by 5 publications

(6 citation statements)

References 20 publications

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“…25 For example, the conformational composition, separation on the GTC, and identification by chromatography coupled with mass spec trometry of stereoisomeric perhydrothioxanthenes, per hydroxanthenes, and perhydro 4 thia s indacenes have been studied earlier. 24,[33][34][35] Good agreement between the experimental and theoretically calculated TCA values (in particular, К 1,С and q -dif,1 ) for diverse stereoisomers was established 24,33-35 when the earlier 27,28 determined AAP parameters were used in the form of Eq. (2).…”

Section: Resultsmentioning

confidence: 99%

Molecular statistical calculation of thermodynamic characteristics of adsorption of O-, S-, and Se-containing heteroadamantanes on graphitized thermal carbon black

Yashkin

Svetlov²,

Murashov³

2010

Russ Chem Bull

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The thermodynamic characteristics of adsorption (TCA) on the basal face of graphite have been calculated in terms of the semiempirical molecular statistical theory of adsorption for molecules of O , S , and Se containing heteroadamantanes of different structure and isostructural cyclohexane derivatives. The influence of the nature, number, and position of heteroatoms in the adamantane framework on the TCA values was studied in detail, which made it possible to predict the retention of the compounds considered on the surface of graphitized thermal carbon black under the conditions of equilibrium gas adsorption chroma tography. The introduction of each subsequent heteroatom into a polyheteroadamantane molecule makes a non additive contribution to the TCA values. The contributions of various fragments to the total adsorption energy were calculated by the TCA of isostructural heterocyclohexane molecules, and the most preferential orientations of the framework molecules of the adsorbates relative to the planar graphite surface were determined.

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Section: Resultsmentioning

confidence: 99%

Molecular statistical calculation of thermodynamic characteristics of adsorption of O-, S-, and Se-containing heteroadamantanes on graphitized thermal carbon black

Yashkin

Svetlov²,

Murashov³

2010

Russ Chem Bull

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“…The theoretically unexpected stereoisomer X7 of mixture 2, assumed to be conformer B of cis-syn-cis-PHX, coeluted from the column packed with GTCB with one of the other stereo- isomers. 1 The hypothetical molecular structure of this conformer was considered on the assumption that all rings are in the chair conformation. A possible intermediate conformation with the middle ring as a boat was not considered because the structure is not quasi-rigid and the calculations according to eqn.…”

Section: Resultsmentioning

confidence: 99%

“…In our previous work the existence of seven stereoisomeric forms of perhydroxanthene (PHX), three of which are known [cis-syn-cis (A), trans-anti-cis, trans-syn-trans], was established. 1 The structure elucidation of the four novel PHX stereoisomers appeared more difficult, as compared with PHTX studied earlier, 2 due to the similarity of the electron impact mass spectra and the existence of the seventh theoretically unexpected stable stereoisomeric form. 1 Nevertheless, cis-anti-cis and transanti-trans isomers were the preliminary assignments.…”

Section: Introductionmentioning

confidence: 93%

“…1 The structure elucidation of the four novel PHX stereoisomers appeared more difficult, as compared with PHTX studied earlier, 2 due to the similarity of the electron impact mass spectra and the existence of the seventh theoretically unexpected stable stereoisomeric form. 1 Nevertheless, cis-anti-cis and transanti-trans isomers were the preliminary assignments. From the data obtained it might be concluded that a qualitative relationship between the retention order and molecular geometry of isomers cannot be considered to be reliable if their mass spectra are indistinguishable or very similar.…”

Section: Introductionmentioning

confidence: 93%

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Gas chromatography–mass spectrometry of the stereoisomers of heterocyclic compounds. Part 2b.1 Perhydroxanthenes

Kulikov¹,

Bobyleva²

1998

J. Chem. Soc., Perkin Trans. 2

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The quantitative relationships between the retention of the stereoisomers of perhydroxanthene (PHX) on a column packed with graphitized thermal carbon black (GTCB) and their hypothetical molecular structures optimized by molecular mechanics have been established. From the GC-MS data obtained the structure of four novel stereoisomers have been elucidated. Along with the theoretically expected trans-anti-trans-, trans-syn-cis-and cis-anti-cis-isomers, the unusual stable stereoisomeric form of PHX has been found and elucidated as conformer B of the cis-syn-cis-isomer. The evidence for this assignment based on the obtained GC-and MS-data is discussed.

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“…[10][11][12] The atomic coordinates of adsorbate molecules, required by this method, were obtained after energy minimization of their hypothetical structures by molecular mechanics according to the approach successfully tried out earlier. 6,7,12 This results in plots of the dependence of ln K 1 on the reciprocal temperature 1/T which are shown in Fig. 4.…”

Section: Trans-syn-trans Trans-anti-trans Trans-anti-cis Trans-syn-ci...mentioning

confidence: 98%

Gas chromatography–mass spectrometry of the stereoisomers of heterocyclic compounds. Part 3.† Perhydro-4-thia-s-indacene

Kulikov

Bobyleva

2000

J. Chem. Soc., Perkin Trans. 2

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A gas chromatographic-mass spectrometric study of mixtures of the stereoisomers of perhydro-4-thia-s-indacene (PHTI) has been carried out. Separation has been accomplished on a column packed with graphitized thermal carbon black (GTCB) and on a capillary column of high efficiency. In addition to the known cis-syn-cis isomer, five novel diastereomers have been found. The stereospecificity of their fragmentation under electron impact appeared to be quite distinct and mass spectra (70 eV) of cis-cis, trans-cis and trans-trans conjugated isomers were distinguished. An important part in the structural elucidation of the novel isomers is played by molecular statistical calculations of the thermodynamic parameters of their adsorption on GTCB, which were performed on the basis of hypothetical molecular structures of these compounds optimized by molecular mechanics. Evidence for the existence of cis-cis isomers with the middle ring in a boat conformation obtained from these data is discussed.

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Gas chromatography–mass spectrometry of the stereoisomers of heterocyclic compounds. Part 2a.1 Perhydroxanthenes

Cited by 5 publications

References 20 publications

Molecular statistical calculation of thermodynamic characteristics of adsorption of O-, S-, and Se-containing heteroadamantanes on graphitized thermal carbon black

Molecular statistical calculation of thermodynamic characteristics of adsorption of O-, S-, and Se-containing heteroadamantanes on graphitized thermal carbon black

Gas chromatography–mass spectrometry of the stereoisomers of heterocyclic compounds. Part 2b.1 Perhydroxanthenes

Gas chromatography–mass spectrometry of the stereoisomers of heterocyclic compounds. Part 3.† Perhydro-4-thia-s-indacene

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