THE SAPONIN OF CHINESE DRUG BAI-TOU-WENG III. THE STRUCTURE OF ANEMOSAPOGENIN

The structure of anemosapogenin 1 has been proved to be 3β, 23-dihydroxylup-20 (29)-en-28-oic acid on the basis of spectroscopic(IR, ~1H NMR、~(13)C NMR, MS) evidences and chemical transformations, namely, the formation of acetonide 3 from 6, the acid catalysed rearrangement of 1 and 2 into 18 (α)-oleanan-28, 19β-olide derivatives 4 and 5 respectively and finally, the conversion of 7 through LiAlH_4 reduction into the known compound, lup-20(29)-ene-3β, 23, 28-triol. The third sugar component of the saponin is shown to be arabinose.