CIRCULAR-DICHROISM SPECTROSCOPY OF 2-AMINOTETRALINS

The circular dichroism (CD) spectra of a series of oxygenated 2-(dipro pylamino)tetralin derivatives are reported. On the basis of known abso lute configurations and conformational preferences of the compounds, t he validity of published correlations between the sign of the (1)L(b) Cotton effect and the three-dimensional structure was examined. Contra ry to predictions, substitution in position 6 or 7 of the tetralin moi ety did not change the sign of the (1)L(b) Cotton effect. An unexpecte d sign inversion was, however, observed in some of the compounds conta ining methyl substituents in the nonaromatic ring. The occurrence of t his inversion was not correlated with a change in conformational behav iour and varied depending on the position and nature of the aromatic s ubstituent. No correlations were obvious between the sign of the (1)L( b) Cotton effect and the absolute configuration and conformational pre ferences of the compounds. Therefore, at present, CD spectroscopy does not appear to be useful in assignments of the absolute configurations of 2-(dipropylamino)tetralin derivatives. (C) 1995 Wiley-Liss, Inc.