Influence of intramolecular hydrogen bonding on the conformational equilibrium of cis-3-N,N-dimethylaminocyclohexanol compared with trans-3-N,N-dimethylaminocyclohexanol and cis- and trans-3-N,N-dimethylamino-1-methoxycyclohexane

dc.creatorde Oliveira, PR
dc.creatorRibeiro, DS
dc.creatorRittner, R
dc.date2005
dc.dateJUN
dc.date2014-11-15T09:11:20Z
dc.date2015-11-26T16:10:17Z
dc.date2014-11-15T09:11:20Z
dc.date2015-11-26T16:10:17Z
dc.date.accessioned2018-03-28T22:58:54Z
dc.date.available2018-03-28T22:58:54Z
dc.identifierJournal Of Physical Organic Chemistry. John Wiley & Sons Ltd, v. 18, n. 6, n. 513, n. 521, 2005.
dc.identifier0894-3230
dc.identifierWOS:000229295200006
dc.identifier10.1002/poc.896
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/80189
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/80189
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/80189
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1266834
dc.descriptionH-1 NMR data show that concentration increase shifts the conformational equilibrium of cis-3-N,N-dimethylaminocyclohexanol (1) (cis-3-DACH) from the 1aa conformer, stabilized by an intramolecular hydrogen bond (IAHB), to the lee conformer [43% (0.01 m) to 70% (0.40 m), in CCl4], which can form intermolecular hydrogen bonds (IEHB). The percentage of lee conformer also increases with the solvent basicity from 36% in C6D to 89% in DMSO. The conformational equilibrium of the trans isomer (trans-3-DACH) is also dependent on concentration, since 1ae increases from 77% (0.05 m) to 84% (0.40 m) in CCl4 but not with the solvent polarity. The occurrence of an IAHB in cis-3-DACH was confirmed by the study of a model compound, cis-3-N,N-dimethylamino-l-methoxycyclohexane (2) (cis-3-DAMCH), lacking an OH group and presenting a single conformer 2ee (similar to 95%). The corresponding trans isomer (trans-3-DAMCH) behaves similarly to trans-3-DACH, since the 2ae conformer occurs as similar to 83%, in the studied solvents. The PCMODEL program gave very good coupling constant values for the qualitative analysis of energy changes in the study of concentration and solvent effects, since the energy values obtained for cis and trans isomers of 3-DACH were in good agreement with the theoretically calculated [B3LYP/6311 +g(d,p) level] values. The averaged calculated energy of the IAHB, for conformer 1aa of cis-3-DACH, with optimization of the reference structure and at several levels of theory, is 5.74 kcal mol(-1) (1 kcal = 4.184 kJ). Copyright (c) 2005 John Wiley & Sons, Ltd.
dc.description18
dc.description6
dc.description513
dc.description521
dc.languageen
dc.publisherJohn Wiley & Sons Ltd
dc.publisherChichester
dc.publisherInglaterra
dc.relationJournal Of Physical Organic Chemistry
dc.relationJ. Phys. Org. Chem.
dc.rightsfechado
dc.rightshttp://olabout.wiley.com/WileyCDA/Section/id-406071.html
dc.sourceWeb of Science
dc.subjectconformational analysis
dc.subjecttheoretical calculations
dc.subjectintramolecular hydrogen bond
dc.subjectNMR spectroscopy
dc.subjectNmr
dc.subjectThioxoketones
dc.subjectDerivatives
dc.subjectSystems
dc.subjectRings
dc.titleInfluence of intramolecular hydrogen bonding on the conformational equilibrium of cis-3-N,N-dimethylaminocyclohexanol compared with trans-3-N,N-dimethylaminocyclohexanol and cis- and trans-3-N,N-dimethylamino-1-methoxycyclohexane
dc.typeArtículos de revistas


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