17α-dihydroequilenin 17α-dihydroequilenin 17α-dihydroequilenin, or α-dihydroequilenin, also known as 6,8-didehydro-17α-estradiol, as well as estra-1,3,5(10),6,8-pentaen-3,17α-diol, is a naturally occurring steroidal estrogen found in horses which is closely related to equilin, equilenin, and 17α-estradiol, and, as the 3-sulfate ester sodium salt, is a minor constituent (1.2%) of conjugated estrogens (premarin). not to be confused with 17α-dihydroequilin, 17β-dihydroequilin, or 17β-dihydroequilenin. 17α-dihydroequileninclinical dataother namesnsc-12171; α-dihydroequilenin; 6,8-didehydro-17α-estradiol; estra-1,3,5(10),6,8-pentaen-3,17α-diolroutes ofadministrationby mouthdrug classestrogenidentifiers iupac name (13s,14s,17r)-13-methyl-11,12,14,15,16,17-hexahydrocyclopentaphenanthrene-3,17-diol cas number6639-99-2pubchem cid223998chemspider194598chebichebi:34178chemblchembl135236echa infocard100.026.955 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-kszliroesa-n