Hydroacridines XIX. C-13 NMR spectra of several N-alkyl-tetradecahydroacridines and their protonated species: Investigation of the N-epimeric equilibria of the N-alkyl groups in the amines and in the salts

(4a alpha,8a beta,9a beta,10a alpha)-Tetradecahydro-10-methylacridin, (4a a lpha,8a beta,9a beta,10a alpha)-10-ethyltetradecahydroacridin, (4a alpha,8a beta,9a beta,10a alpha)-tetradecahydro-10-methylacridine, (4a alpha,8a alp ha,9a beta,10a alpha)-10-ethyl-tetradecahydroacridin and their products of protonation with trifluoroacetic acid were studied by C-13 NMR spectroscopy . The first two amines give rise to a pair of N-diastereomeric salts, where as the latter two yield only the salts with equatorial N-alkyl groups. The N-epimeric equilibria of the N-alkyl groups (equatorial-axial) in the salts and in the amines are discussed.