Shielding effect of thioether C–S bond from proton chemical shifts of 4-thia-5α- and 4-thia-5β-androstane-17-ones
摘要:
4-Thia-5 alpha- and 4-thia-5 beta-androstan-17-ones (1a and 1b) were synthesized in order to obtain the NMR shielding parameters for the thioether C-S bond. The complete NMR assignment of both the proton and carbon atoms for these compounds and substituent-induced shifts (SIS) from the corresponding androstanones (2a and 2b) are presented. A combination of the electric field effect and the anisotropy of the magnetic susceptibility of the C-S bond can successfully reproduced the observed SIS values for these androstanones. (c) 2005 Elsevier Ltd. All rights reserved.
Shielding effect of thioether C–S bond from proton chemical shifts of 4-thia-5α- and 4-thia-5β-androstane-17-ones
摘要:
4-Thia-5 alpha- and 4-thia-5 beta-androstan-17-ones (1a and 1b) were synthesized in order to obtain the NMR shielding parameters for the thioether C-S bond. The complete NMR assignment of both the proton and carbon atoms for these compounds and substituent-induced shifts (SIS) from the corresponding androstanones (2a and 2b) are presented. A combination of the electric field effect and the anisotropy of the magnetic susceptibility of the C-S bond can successfully reproduced the observed SIS values for these androstanones. (c) 2005 Elsevier Ltd. All rights reserved.