On the Structure of Licoricidin

A prenylated isoflavan isolated from Sipei licorice (Glycyrrhiza sp., Legumlnosae, Seihoku Kanzo in Japanese) was proved to be identical with already known compound licoricidin (2).From the spectral data, the structure (2) of licoricidin should be revised to the structure (1).L~corice, the root of various species of Glycyrrhiza (Legurninosae), has been used for a long time as a very important crude drug.The constituents of the crude drug have been studied by many investigators, and a series of prenylated flavonoids have been isolated.' in the course of our studies on the prenylated phenols from the crude drugsS2 the studies were carried out on the phenolic compounds of Sipei licorice (Glycyrrhiza sp., Leguminosae, Seihoku Kanzo in ~apanese1.lFrom the benzene extract of the crude drug (4.8 Kg), a prenylated isoflavan 11, 500 mg) was isolated by using column chromatography lsillca gel, n-hexane-benzene as eluent) and by preparative tlc (silica gel, CHCl .acetone= 3 ' 10:l.developing solvent), successively.Compound (1) was obtained as colorless needles, mp 161 'c, [dl? +22.8' (c=0.412,MeOH), negative to ferric chloride test.The compound (1) showed the following MeOH spectra; Ir J:::