The conformational equilibrium of 1,3-dichloro-5-methylcyclohexane
Abstract
Two of the stereoisomers of the title compound were prepared and their dipole moments were measured. For the r-1,c-3-dichloro-t-5-methylcyclohexane, the free energy difference between conformers with axial-axial (aa) and equatorial-equatorial (ee) chlorines was measured by a variable temperature NMR method, and the value found was 1.3 ± 0.2 Kcal/mol-1 (in acetone) favoring the latter. Molecular mechanics studies show that the solvation energy and the electrostatics are of major importance in understanding this equilibrium. Calculations show the effect of the methyl group is essentially additive, and give for cis-1,3-dichlorocyclohexane itself ee{measured angle}aa DH+ 3.0 kcal mol-1 (acetone).
Keywords:
stereoisomers / chlorines / electrostatics / molecular mechanics (MM) / methyl / conformations / free energy / cyclohexaneSource:
Tetrahedron, 1981, 37, 20, 3455-3461Publisher:
- Elsevier
Funding / projects:
- The Research Fund of the Republic of Serbia
DOI: 10.1016/S0040-4020(01)98859-3
ISSN: 0040-4020; 1464-5416
Scopus: 2-s2.0-49149133610
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Institution/Community
IHTMTY - JOUR AU - Došen-Mićović, Ljiljana AU - Jeremić, Dragoslav AU - Allinger, Norman L. PY - 1981 UR - https://cer.ihtm.bg.ac.rs/handle/123456789/4423 AB - Two of the stereoisomers of the title compound were prepared and their dipole moments were measured. For the r-1,c-3-dichloro-t-5-methylcyclohexane, the free energy difference between conformers with axial-axial (aa) and equatorial-equatorial (ee) chlorines was measured by a variable temperature NMR method, and the value found was 1.3 ± 0.2 Kcal/mol-1 (in acetone) favoring the latter. Molecular mechanics studies show that the solvation energy and the electrostatics are of major importance in understanding this equilibrium. Calculations show the effect of the methyl group is essentially additive, and give for cis-1,3-dichlorocyclohexane itself ee{measured angle}aa DH+ 3.0 kcal mol-1 (acetone). PB - Elsevier T2 - Tetrahedron T1 - The conformational equilibrium of 1,3-dichloro-5-methylcyclohexane VL - 37 IS - 20 SP - 3455 EP - 3461 DO - 10.1016/S0040-4020(01)98859-3 ER -
@article{ author = "Došen-Mićović, Ljiljana and Jeremić, Dragoslav and Allinger, Norman L.", year = "1981", abstract = "Two of the stereoisomers of the title compound were prepared and their dipole moments were measured. For the r-1,c-3-dichloro-t-5-methylcyclohexane, the free energy difference between conformers with axial-axial (aa) and equatorial-equatorial (ee) chlorines was measured by a variable temperature NMR method, and the value found was 1.3 ± 0.2 Kcal/mol-1 (in acetone) favoring the latter. Molecular mechanics studies show that the solvation energy and the electrostatics are of major importance in understanding this equilibrium. Calculations show the effect of the methyl group is essentially additive, and give for cis-1,3-dichlorocyclohexane itself ee{measured angle}aa DH+ 3.0 kcal mol-1 (acetone).", publisher = "Elsevier", journal = "Tetrahedron", title = "The conformational equilibrium of 1,3-dichloro-5-methylcyclohexane", volume = "37", number = "20", pages = "3455-3461", doi = "10.1016/S0040-4020(01)98859-3" }
Došen-Mićović, L., Jeremić, D.,& Allinger, N. L.. (1981). The conformational equilibrium of 1,3-dichloro-5-methylcyclohexane. in Tetrahedron Elsevier., 37(20), 3455-3461. https://doi.org/10.1016/S0040-4020(01)98859-3
Došen-Mićović L, Jeremić D, Allinger NL. The conformational equilibrium of 1,3-dichloro-5-methylcyclohexane. in Tetrahedron. 1981;37(20):3455-3461. doi:10.1016/S0040-4020(01)98859-3 .
Došen-Mićović, Ljiljana, Jeremić, Dragoslav, Allinger, Norman L., "The conformational equilibrium of 1,3-dichloro-5-methylcyclohexane" in Tetrahedron, 37, no. 20 (1981):3455-3461, https://doi.org/10.1016/S0040-4020(01)98859-3 . .