4-hydroxyethynylestradiol

17a-Ethynylestra-1,3,5(10)-triene-3,4,17-triol

19-Nor-17a-pregna-1,3,5(10)-trien-20-yne-3,4,17-triol

(17a)-19-Norpregna-1,3,5(10)-trien-20-yne-3,4,17-triol