ent-estradiol ent-estradiol ent-estradiol (ent-e2), or 1-estradiol (1-e2), is an estrogen and the 1-enantiomorph of estradiol. it is a so-called "short-acting" or "impeded" estrogen, similarly to estriol, 17α-estradiol, and dimethylstilbestrol. ent-estradiolclinical dataother namesent-e2; 1-estradiol; 1-e2drug classestrogenidentifiers iupac name (8s,9r,13r,14r,17r)-13-methyl-6,7,8,9,11,12,14,15,16,17-decahydrocyclopentaphenanthrene-3,17-diol cas number3736-22-9 ypubchem cid667515uniivw299dj6u7comptox dashboard (epa)dtxsid60912332 chemical and physical dataformulac18h24o2molar mass272.388 g·mol−13d model (jsmol)interactive image smiles c12cc3(1cc2o)ccc4=c3c=cc(=c4)o inchi inchi=1s/c18h24o2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h3,5,10,14-17,19-20h,2,4,6-9h2,1h3/t14-,15-,16+,17+,18+/m0/s1key:voxzdwnpvjitmn-qxdignsfsa-n