Triterpenoids. Part XXVIII. Conversion of eburicoic acid into 4,4,14α-trimethylpregn-8-ene-2,7,11,20-tetraone
A new and convenient sequence for the conversion of the eburicoic acid side-chain into a methyl ketone group has been developed. In this way 4,4,14α-trimethylpregn-8-ene-3,20-dione (VI) is readily available. The latter compound has been transformed by known reactions into 4,4,14α-trimethylpregn-8-ene-2,7,11,20-tetraone (XII), a key compound in the correlation of the lanosterol triterpenoids with the cucurbitacins.