Journal of the Chilean Chemical Society
versión On-line ISSN 0717-9707
ITURRIAGA-VASQUEZ, PATRICIO; ZAPATA-TORRES, GERALD; CAROLI REZENDE, MARCOS y CASSELS, BRUCE K.. 1-BENZYL-1,2,3,4-TETRAHYDROISOQUINOLINES: 1H NMR CONFORMATIONAL STUDIES AND ROTATIONAL BARRIERS. J. Chil. Chem. Soc. [online]. 2004, vol.49, n.1, pp. 17-23. ISSN 0717-9707. http://dx.doi.org/10.4067/S0717-97072004000100004.
The conformational preferences of a series of 1-benzyl-1,2,3,4-tetrahydroisoquinolines (norlaudanosine and coclaurine analogues) were investigated with the aid of their 1H NMR spectra and NOESY experiments, coupled with ab initio theoretical studies to estimate energy barriers among the various stable conformers of these systems. The secondary amines prefer an extended conformation, while the N-alkylated derivatives prefer a semi-folded one, with considerable freedom to exchange between both forms. A third, folded conformation, although not much higher in energy, is relatively inaccessible
Palabras llave : 1-benzyl-1,2,3,4-tetrahydroisoquinolines; conformation; NMR studies; RHF/6-31g(d,p) calculations.