Thermal degradation of glycosides, II. Thermal effect on acetates of typical triterpenoid and steroid glycosides

The termal effect on acetates of triterpenoid and steroid glycosides was examined. Contrary to the case of free glycosides, on heating the acetates of typical triterpenoid and steroid glycosides (including cardiac glycosides) on a melting point apparatus the cleavage reactions of sugar–aglycone and sugar–sugar linkage did not take place, and no aglycones or prosapogenins were obtained. However, two interesting and useful reactions did occur in the course of thermolysis of cardiac glycoside acetates. By taking into account the thermal effect on the glycoside acetates, and their FD mass spectra, an important suggestion on the mechanism of FD mass fragmentation of the glycosidic linkage was obtained.