Hydroacridines XXI . C-13 NMR spectroscopic investigation of the stereoselectivities of quaternizations of N-alkyl derivatives of (4a alpha,8a beta,9a beta,10a alpha)- and (4a alpha,8a alpha,9a beta,10a alpha)-tetradecahydroacridine

The stereoselectivities of the quaternization reactions of (4a alpha,8a bet a,9a beta,10a alpha)- and (4a alpha,8a alpha,9a beta,10a alpha)-tetradecahy dro-10-methylacridine with methyl- and ethyl iodide as well as those of (4a alpha,8a beta,9a beta,10a alpha)- and (4a alpha,8a alpha,9a beta,10a alpha )-10-ethyl-tetradecahydroacridine with methyl iodide were investigated usin g C-13 NMR spectroscopy including C-13-labelling where appropriate. The met hylations of both N-methyl amines occur by predominant (60% and 75%, respec tively) equatorial approach, their ethylations occur sterospecifically by e quatorial approach, and the methylations of the N-ethyl amines occur by hig hly stereoselective (>90%) axial approach of the quaternizing reagent.