Resin glycosides. XIX. Woodrosins I and II, ether-insoluble resin glycosides from the stems of Ipomoea tuberosa.

Two new ether-insoluble resin glycosides named woodrosins I and II were isolated from the stems of Ipomoea tuberosa L., and their structures were determined on the basis of chemical and spectral data. Contrary to anticipation, they had an intramolecular cyclic ester structure similar to that of ether-soluble resin glycosides (Mayer's jalapin) hitherto isolated. It is proposed to use the terms, "jalapin" and "convolvulin," not according to the solubility in ether (Mayer's classification), but according to the structure, i.e., intramolecular esters and others, respectively.