Anisochrony of isopropyl methyl groups in 1-isopropyl-substituted tetralins and indans
作者:N. Pourahmady、V. A. Palaniswamy、E. J. Eisenbraun
DOI:10.1002/omr.1270211106
日期:1983.11
Abstract1‐Isopropyl‐5‐methylindan, 1‐isopropyl‐7‐methylindan and 1‐isopropyl‐1,2,3,4‐tetrahydronaphthalene show a large anisochrony (magnctic non‐equivalence) of the isopropyl methyl signals at room temperature in their1H NMR spectra. A decrease in magnitude of this anisochrony is observed, in each case, in the temperature range 30‐150 °C. However, for 1‐isopropyl‐8‐methyltetralin, the magnitude of the non‐equivalence of the isopropyl methyl signals is unexpectedly small. These latter signals converge at 85 °C and then diverge in the opposite direction over the range 85‐150 °C. This alteration in anisochrony with temperature change for all cases is observed as a continuous downfield migration of one signal which, in turn, results from variations in conformation populations.