It has been described in the literature1that the protonation of the nitrogen in 1-benzyl-1,2,3,4-tetraisoquinoline derivatives does not affect the sign of the ORD spectra. We have recently observed2that in the case of several (R) and (S) N-methyl-4-phenyl-1,2,3,4-tetrahydroisoquinol ine derivatives this is true only for the three Cotton effects below 300 nm (the1Lb,1Laand1B electronic transitions3of the aromatic moiety), although appreciable variations in intensity and slight shifts in the positions of the extrema were also noticed. On the other hand, the sign of the rotation in the visible spectral range was reversed upon protonation in 0.1N methanolic HCl (or hydrochloride of1in methanol).