Batta A K, Williams T H, Salen G, Greeley D N, Shefer S
J Lipid Res. 1980 Jan;21(1):130-5.
This study was designed to examine whether 13C nuclear magnetic resonance (NMR) spectroscopy can be used to differentiate between the 25R and 25S diastereoisomers of 5 beta-cholestane-3 alpha, 7 alpha, 26-triol, a key intermiediate in the biosynthetic pathway of chenodeoxycholic acid. Chemical shift values were assigned to the individual carbon atoms with the help of model compounds and multiplicity in the single-frequency off-resonance decoupled spectra. It was found that the corresponding carbons 1-20 afforded identical chemical shifts for both compounds, whereas five of the remaining side-chain carbons gave observed shift differences of 0.05-0.20 ppm. Thus 13C NMR can be used as an additional tool to distinguish between the two 5 beta-cholestanetriols isomeric at C-25.
本研究旨在考察13C核磁共振（NMR）光谱法能否用于区分鹅去氧胆酸生物合成途径中的关键中间体5β-胆甾烷-3α，7α，26-三醇的25R和25S非对映异构体。借助模型化合物和单频偏共振去耦谱中的多重性，为各个碳原子指定了化学位移值。结果发现，两种化合物的相应碳1至20给出了相同的化学位移，而其余五个侧链碳给出了0.05 - 0.20 ppm的观测位移差异。因此，13C NMR可作为区分C-25位异构的两种5β-胆甾三醇的额外工具。
