13C NMR spectral assignment of five epimeric 3alpha- versus 3beta-functionalized cholestane pairs.
(13)C NMR chemical shift assignments of five alpha- and beta- epimeric pairs of cholestanes functionalized at C-3 are presented. Empirical increment estimations proved to be a valuable tool for the unequivocal structural elucidation when compared with the chemical shift values of cholestanes derivatized by introduction of N- and S-containing groups at C-3 in equatorial and axial positions. Moreover, the possibility is demonstrated to anticipate the effect of -OC(S)R substituents at neighboring carbon atoms of the ring A backbone.
Ramos
S S
SS
INETI, Instituto Nacional de Engenharia, Tecnologia e Inovação, I.P., Estrada do Paço do Lumiar, 1649-038 Lisboa, Portugal.
Santos
L
L
Almeida
P
P
Motherwell
W B
WB
Costa
M C
MC
D002247:Carbon Isotopes; D002776:Cholestanes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000592:standards*; D008968:Molecular Conformation; D012015:Reference Standards
D002247:Carbon Isotopes; D002776:Cholestanes