(r,r)-tetrahydrochrysene (r,r)-tetrahydrochrysene (r,r)-tetrahydrochrysene ((r,r)-thc) is a drug used to study the estrogen receptors (ers) in scientific research. it is an erβ antagonist and an erα agonist with 10-fold higher affinity for erβ relative to erα. (r,r)-thc is a silent antagonist of erβ, and, uniquely relative to other known erβ antagonists, a passive antagonist of the receptor. (r,r)-tetrahydrochryseneidentifiers iupac name (5r,11r)-5,11-diethyl-5,6,11,12-tetrahydrochrysene-2,8-diol cas number138090-06-9 ypubchem cid446849chemspider394097unii89htc2nwf3chebichebi:42371chemical and physical dataformulac22h24o2molar mass320.432 g·mol−13d model (jsmol)interactive image smiles ccc1cc2=c(c=cc(=c2)o)c3=c1c4=c(cc3cc)c=c(c=c4)o inchi inchi=1s/c22h24o2/c1-3-13-9-15-11-17(23)6-8-20(15)22-14(4-2)10-16-12-18(24)5-7-19(16)21(13)22/h5-8,11-14,23-24h,3-4,9-10h2,1-2h3/t13-,14-/m1/s1key:masyawhpjcqlsw-ziagygmssa-n (s,s)-tetrahydrochrysene ((s,s)-thc) also binds to the ers, but in contrast to (r,r)-thc, (s,s)-thc is an agonist of both erα and erβ and has 20-fold lower affinity for erβ relative to (r,r)-thc.