19-NORCARDENOLIDES

Article abstract of DOI:10.1007/BF00574252

The products of the autooxidation of the cardenolides strophanthidin and erysimin in solutions have been studied.It has been established that the autooxidation of 19-oxocardenolides forms, together with 19-carboxylic acids, a complex mixture of 19-norcardenolides.The bulk of them consists of 10β-OH compounds and a smaller proportion of 10β-H compounds.Autooxidation affects both the functional group at C-10 and its transformation and also other groupings and bonds in ring A and, to some extent, in ring B, including the oxidation of the 3β-OH group, degradation of the 5β-OH group, and cleavage of the C5-C10 bond with the formation of 5,10-seco-19-norcardenolides.A possible mechanism of the formation of 19-norcardenolides is discussed.