Resumo

GERLI C, LORENA A; SALAS, M. PAULINA  e  CONTRERAS, J. GUILLERMO. STUDY OF THERMODYNAMIC AND NMR PROPERTIES OF SOME CYCLOHEXANE DERIVATIVES. J. Chil. Chem. Soc. [online]. 2011, vol.56, n.4, pp.922-925. ISSN 0717-9707.  http://dx.doi.org/10.4067/S0717-97072011000400021.

The preferential conformations of a series of six-membered saturated heterocycles containing oxygen and sulfur atoms, 4-alkyl-6-methyl-1,3-dithiane, with alkyl=methyl, ethyl, propyl, isobuthyl, terbuthyl have been studied by means of ab-initio theoretical methods. The chair conformation is the most stable structure found for all compounds studied here, likewise in its counterparts: cyclohexane, dithiane, and dioxane. The structures show anomalous effects of the chemical shifts, in C2 and C5, due to a σ C-S → σ* C-Hec hyperconjugative interaction. They are also affected by normal Perlin effect in C2, where C2-Hec coupling constants are larger than C2-Hax.

Palavras-chave : 4-alkyl-6-methyl-1,3-dithiane; conformational analysis; NMR.

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