Artículos de revistas
1-benzyl-1,2,3,4-tetrahydroisoquinolines. H-1 NMR conformational studies and rotational barriers
Fecha
2004-03Registro en:
JOURNAL OF THE CHILEAN CHEMICAL SOCIETY 49 (1): 17-23 MAR 2004
0717-9324
Autor
Iturriaga-Vásquez, Patricio
Zapata Torres, Gerald Amilcar
Caroli Rezende, Marcos
Cassels Niven, Bruce
Institución
Resumen
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 H-1 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.