The conformational energies of 2-methyl- and 4-methyl-1,3-dithiane. The breakdown of 1,3-syn diaxial repulsion hypothesis

dc.creatorRibeiro, DS
dc.creatorRittner, R
dc.date2003
dc.dateSEP 10
dc.date2014-11-13T12:44:24Z
dc.date2015-11-26T18:07:21Z
dc.date2014-11-13T12:44:24Z
dc.date2015-11-26T18:07:21Z
dc.date.accessioned2018-03-29T00:49:30Z
dc.date.available2018-03-29T00:49:30Z
dc.identifierJournal Of Molecular Structure. Elsevier Science Bv, v. 657, n. 41699, n. 85, n. 92, 2003.
dc.identifier0022-2860
dc.identifierWOS:000185420500009
dc.identifier10.1016/S0022-2860(03)00357-0
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/74988
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/74988
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/74988
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1293572
dc.descriptionThe conformational enthalpies (DeltaH) of 2-methyl-(-1.76 kcal mol(-1)) and 4-methyl-1,3-dithiane (-1.75 kcal mol(-1)) were obtained by the analysis of C-13 chemical shifts as a function of temperature. These energies are in excellent agreement both with calculated values (B3LYP/6-31G(d,p)) and with literature values based on 2,4-dialkyl-1,3-dithiane. The results confirm the similarity between the conformational energies of the methyl group at the 2 and 4 positions of the dithiane ring and that of methylcyclohexane, despite the larger distances between ring 1,3-syn-axial hydrogens and the closest methyl axial hydrogen in the dithiane ring. The possibility of a buttressing effect on the 2,4-dialkyl-1,3-dithianes previously studied and the rationale of 1,3-syn-axial steric interaction are discussed. (C) 2003 Elsevier B.V. All rights reserved.
dc.description657
dc.description41699
dc.description85
dc.description92
dc.languageen
dc.publisherElsevier Science Bv
dc.publisherAmsterdam
dc.publisherHolanda
dc.relationJournal Of Molecular Structure
dc.relationJ. Mol. Struct.
dc.rightsfechado
dc.rightshttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
dc.sourceWeb of Science
dc.subjectdithianes
dc.subjectVT NMR
dc.subjectconformational equilibrium
dc.subjectsyndiaxial repulsions
dc.subjectMagnetic-resonance Spectra
dc.subjectSaturated Heterocycles
dc.subjectAlkyl Substituents
dc.subject6-membered Rings
dc.subjectC-13
dc.subjectMethyl
dc.subjectEquilibria
dc.subject1,3-dithianes
dc.subjectPreferences
dc.subjectCyclohexane
dc.titleThe conformational energies of 2-methyl- and 4-methyl-1,3-dithiane. The breakdown of 1,3-syn diaxial repulsion hypothesis
dc.typeArtículos de revistas


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