๐”– Bobbio Scriptorium
โœฆ   LIBER   โœฆ

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

โœ Scribed by Hajime Iwamoto; Yoshiaki Kondo; Takefumi Kawatani; Takeharu Haino; Yoshimasa Fukazawa

Publisher
Elsevier Science
Year
2003
Tongue
French
Weight
159 KB
Volume
44
Category
Article
ISSN
0040-4039

No coin nor oath required. For personal study only.

โœฆ Synopsis

4-Aza-5a-androstanone(1a) and 4-aza-5b-androstanone(1b) 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.

๐Ÿ“œ SIMILAR VOLUMES

Carbon-13 NMR studies of oxazolidines, N
Carbon-13 NMR studies of oxazolidines, N-borane-oxazolidines and oxazolidinium salts derived from pseudoephedrine: Steric effect of the BH3 and CH3 groups on the chemical shifts
โœ M. A. Paz-Sandoval; F. Santiesteban; R. Contreras ๐Ÿ“‚ Article ๐Ÿ“… 1985 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 332 KB

Carbon-13 N M R chemical shifts in various oxazolidinea derived from pseudoephedrine and their corresponding N-borane adducts and oxazolidinium salts are examined. The observed shifts can be rationalized on the basis of steric factors, owing to the simiIarity between the borane adducts and the oxazo