1-keto-1,2,3,4-tetrahydrophenanthrene 1-keto-1,2,3,4-tetrahydrophenanthrene 1-keto-1,2,3,4-tetrahydrophenanthrene (thp-1), or 1,2,3,4-tetrahydrophenanthren-1-one, is a synthetic steroid-like compound which was reported to be the first synthetic estrogen, or the first synthetic compound identified with estrogenic activity. it was first synthesized in 1933 by cook et al. and was tested due to its similarity to the presumed chemical structure of estrone. upon reassessment many decades later, the compound was found to bind only weakly to the estrogen receptors, and, unexpectedly, did not actually have functional activity as an estrogen or antiestrogen in vitro or in vivo. it did, however, show some androgenic and antiandrogenic activity in vitro. 1-keto-1,2,3,4-tetrahydrophenanthreneclinical dataother namesthp-1; 1,2,3,4-tetrahydrophenanthren-1-oneidentifiers iupac name 3,4-dihydro-2h-phenanthren-1-one cas number573-22-8 ypubchem cid225683chemspider196209uniiran6r458lnchemblchembl88130comptox dashboard (epa)dtxsid50280072 chemical and physical dataformulac14h12omolar mass196.249 g·mol−13d model (jsmol)interactive image smiles c1cc2=c(c=cc3=cc=cc=c23)c(=o)c1 inchi inchi=1s/c14h12o/c15-14-7-3-6-12-11-5-2-1-4-10(11)8-9-13(12)14/h1-2,4-5,8-9h,3,6-7h2key:kbargpsseixdqu-uhfffaoysa-n