Magnetic shielding effect of amine and ammonium groups obtained from proton chemical shifts of androstane derivatives

4-Aza-5α-androstanone(1α) and 4-aza-5β-androstanone(1β) were synthesized in order to obtain the NMR shielding parameters for the secondary amine group. A combination of the electric field effect and the anisotropy of the magnetic susceptibility of the CN bond can successfully reproduce the observed SIS values for these androstanes. Drastic chemical shift change of protons near-by nitrogen atom of ammonium salt was observed and shielding parameter for the secondary ammonium group was also obtained.