abstract |
The invention concerns a method of preparing 14,17α-etheno- and 14,17α-ethano-16α,17β-steroiddiols and derivatives thereof, in particular 14,17αetheno- and 14,17α-ethano-3,16α,17β-estriols and their esters, which are highly active, orally effective oestrogens, by Diels-Alder addition of a vinyl ester, preferably vinyl acetate, to a 17-alkanoyloxy-14,16-diene. |