17β-dihydroequilenin 17β-dihydroequilenin 17β-dihydroequilenin, or β-dihydroequilenin, also known as δ6,8-17β-estradiol or 6,8-didehydro-17β-estradiol, as well as estra-1,3,5(10),6,8-pentaen-3,17β-diol, is a naturally occurring steroidal estrogen found in horses which is closely related to equilin, equilenin, and estradiol, and, as the 3-sulfate ester sodium salt, is a minor constituent (0.5%) of conjugated estrogens (premarin). 17β-dihydroequilenin has unexpectedly shown a selective estrogen receptor modulator (serm)-like profile of estrogenic activity in studies with monkeys, in which beneficial effects on bone and the cardiovascular system were noted but proliferative responses in breast and endometrium were not observed. not to be confused with 17α-dihydroequilin, 17β-dihydroequilin, or 17α-dihydroequilenin. 17β-dihydroequileninclinical dataother namesβ-dihydroequilenin; δ6,8-17β-estradiol; 6,8-didehydro-17β-estradiol; estra-1,3,5(10),6,8-pentaen-3,17β-diolroutes ofadministrationby mouthdrug classestrogenidentifiers iupac name (13s,14s,17s)-13-methyl-11,12,14,15,16,17-hexahydrocyclopentaphenanthrene-3,17-diol cas number1423-97-8pubchem cid3032407chemspider2297390chemblchembl123405comptox dashboard (epa)dtxsid40931405 chemical and physical dataformulac18h20o2molar mass268.356 g·mol−13d model (jsmol)interactive image smiles c12ccc3=c(1cc2o)c=cc4=c3c=cc(=c4)o inchi inchi=1s/c18h20o2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h2-5,10,16-17,19-20h,6-9h2,1h3/t16-,17-,18-/m0/s1key:rywzprvuqhmjff-bzsnnmdcsa-n