Secogalioside, an Iridoid Glucoside from Galium album Mill. and 13C NMR Spectra of Some Seco-iridoid Glucosides.

Abstract

The known glucosides asperuloside and arbutin were isolated from G. album in addition to a new iridoid glucoside, named secogalioside. The structure and the absolute configuration were determined by spectroscopic methods and by relating secogalioside to the glucoside sweroside, of known absolute configuration. Three other species of Galium [G. aparine, G. palustre and G. uliginosum] and a hybrid, G. verum .times. album, were devoid of the new compound. 13C NMR spectra of some seco-iridoid glucosides and glucoside acetates were recorded. Assignments of signals were made by using general principles, as well as coupled and selectively decoupled spectra.