Oxidation of triterpenes derived from 18-lupene and 18,19-secolupane with ruthenium tetroxide by an improved procedure

A convenient preparative procedure for the oxidation with ruthernium tetroxide of 18-lupene derivatives to 18,19-secolupane-18,19-dione derivatives in an ethyl acetate-water system has been developed. It has been found that 3β,28-diacetoxy-18,19-secolupane-18,19-dione can be obtained from its 19-(ethylene acetal) or 19-oxime by reaction with ruthenium tetroxide.