δ4-tibolone δ4-tibolone δ4-tibolone (developmental code name org-om-38), also known as 7α-methylnorethisterone or as 7α-methyl-17α-ethynyl-19-nortestosterone, is a synthetic androgen and progestin which was never marketed. the compound is a major active metabolite of tibolone, which itself is a prodrug of δ4-tibolone along with 3α-hydroxytibolone and 3β-hydroxytibolone (which, in contrast to δ4-tibolone, are estrogens). tibolone and δ4-tibolone are thought to be responsible for the androgenic and progestogenic activity of tibolone, while 3α-hydroxytibolone and 3β-hydroxytibolone are thought to be responsible for its estrogenic activity. δ4-tiboloneclinical dataother namesorg-om-38; delta-4-tibolone; 7α-methylnorethisterone; 7α-methyl-17α-ethynyl-19-nortestosterone; 17α-ethynyl-17β-hydroxy-7α-methyl-4-estren-3-oneidentifiers iupac name (7r,8r,9s,10r,13s,14s,17r)-17-ethynyl-17-hydroxy-7,13-dimethyl-1,2,6,7,8,9,10,11,12,14,15,16-dodecahydrocyclopentaphenanthren-3-one cas number1162-60-3 ypubchem cid22814761chemspider18532860uniilhz8r2ow0mchemical and physical dataformulac21h28o2molar mass312.453 g·mol−13d model (jsmol)interactive image smiles c1cc2=cc(=o)cc2314cc(4(cc3)c)(c#c)o inchi inchi=1s/c21h28o2/c1-4-21(23)10-8-18-19-13(2)11-14-12-15(22)5-6-16(14)17(19)7-9-20(18,21)3/h1,12-13,16-19,23h,5-11h2,2-3h3/t13-,16+,17-,18+,19-,20+,21+/m1/s1key:waokmnbzwbgyik-kiurnnqrsa-n