| A pentacyclic hemiacetal steroid was isolated and purified by chromatography with silica gel,Sephadex LH-20 column as well as HPLC.Its plane structure was identified by nuclear magnetic resonance spectroscopy(NMR spectra)and mass spectrometry.By determining and comparing the calculated values of CD,it is determined that the structure of the compound is(8R,9S,10R,13R,14S,17R,18R,20S,22R)-cholesta-1,4-dien-18-al,22-hydroxy-3-oxo-,cyclic 18,22-(acetyl acetal).The compound was isolated from Sinularia sp.for the first time. |