Conformational przferknce of the S→O bond. 1H and 13C NMR studies of the mono-S-oxides of 1,2-, 1,3- and 1,4-dithianes

Eusebio Juaristi, José Guzmán, Vinayak V. Kane, Richard S Glass

Research output: Contribution to journalArticle

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Abstract

The 1H and 13C NMR behavior of the monosulfoxides of 1,2-, 1,3-and 1,4-dithianes (1-3) were studied in order to determine the conformational preference of the S→O bond in these heterocycles. From the results of variable temperature, double irradiation, solvent effects and shift reagent experiments, It is concluded that the axial conformers dominate the conformational equilibria of 1 and 3. On the other hand, 2-equatorial is more stable than 2-axial by 0.64 kcal/mol (ΔG°) at -80°, in CD3OD. This value is essentially identical with the one determined in CHClF2, and the lack of a solvent effect appears to indicate that dipole/dipole interactions do not control this equilibrium. AΔGc = 11.0 kcal/mol was determined for the inversion process of 2. Complete 1H and 13C NMR assignments for 1-3 are presented.

Original languageEnglish (US)
Pages (from-to)1477-1485
Number of pages9
JournalTetrahedron
Volume40
Issue number9
DOIs
StatePublished - 1984

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Oxides
Nuclear magnetic resonance
Irradiation
Temperature
Experiments
Mono-S
1,3-dithiane
1,4-dithiane
Proton Magnetic Resonance Spectroscopy
Carbon-13 Magnetic Resonance Spectroscopy

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Drug Discovery

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Conformational przferknce of the S→O bond. 1H and 13C NMR studies of the mono-S-oxides of 1,2-, 1,3- and 1,4-dithianes. / Juaristi, Eusebio; Guzmán, José; Kane, Vinayak V.; Glass, Richard S.

In: Tetrahedron, Vol. 40, No. 9, 1984, p. 1477-1485.

Research output: Contribution to journalArticle

Juaristi, Eusebio ; Guzmán, José ; Kane, Vinayak V. ; Glass, Richard S. / Conformational przferknce of the S→O bond. 1H and 13C NMR studies of the mono-S-oxides of 1,2-, 1,3- and 1,4-dithianes. In: Tetrahedron. 1984 ; Vol. 40, No. 9. pp. 1477-1485.
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abstract = "The 1H and 13C NMR behavior of the monosulfoxides of 1,2-, 1,3-and 1,4-dithianes (1-3) were studied in order to determine the conformational preference of the S→O bond in these heterocycles. From the results of variable temperature, double irradiation, solvent effects and shift reagent experiments, It is concluded that the axial conformers dominate the conformational equilibria of 1 and 3. On the other hand, 2-equatorial is more stable than 2-axial by 0.64 kcal/mol (ΔG°) at -80°, in CD3OD. This value is essentially identical with the one determined in CHClF2, and the lack of a solvent effect appears to indicate that dipole/dipole interactions do not control this equilibrium. AΔGc‡ = 11.0 kcal/mol was determined for the inversion process of 2. Complete 1H and 13C NMR assignments for 1-3 are presented.",
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N2 - The 1H and 13C NMR behavior of the monosulfoxides of 1,2-, 1,3-and 1,4-dithianes (1-3) were studied in order to determine the conformational preference of the S→O bond in these heterocycles. From the results of variable temperature, double irradiation, solvent effects and shift reagent experiments, It is concluded that the axial conformers dominate the conformational equilibria of 1 and 3. On the other hand, 2-equatorial is more stable than 2-axial by 0.64 kcal/mol (ΔG°) at -80°, in CD3OD. This value is essentially identical with the one determined in CHClF2, and the lack of a solvent effect appears to indicate that dipole/dipole interactions do not control this equilibrium. AΔGc‡ = 11.0 kcal/mol was determined for the inversion process of 2. Complete 1H and 13C NMR assignments for 1-3 are presented.

AB - The 1H and 13C NMR behavior of the monosulfoxides of 1,2-, 1,3-and 1,4-dithianes (1-3) were studied in order to determine the conformational preference of the S→O bond in these heterocycles. From the results of variable temperature, double irradiation, solvent effects and shift reagent experiments, It is concluded that the axial conformers dominate the conformational equilibria of 1 and 3. On the other hand, 2-equatorial is more stable than 2-axial by 0.64 kcal/mol (ΔG°) at -80°, in CD3OD. This value is essentially identical with the one determined in CHClF2, and the lack of a solvent effect appears to indicate that dipole/dipole interactions do not control this equilibrium. AΔGc‡ = 11.0 kcal/mol was determined for the inversion process of 2. Complete 1H and 13C NMR assignments for 1-3 are presented.

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