norendoxifen norendoxifen norendoxifen, also known as 4-hydroxy-n,n-didesmethyltamoxifen, is a nonsteroidal aromatase inhibitor (ai) of the triphenylethylene group that was never marketed. it is an active metabolite of the selective estrogen receptor modulator (serm) tamoxifen. unlike tamoxifen, norendoxifen is not a serm, and instead has been found to act as a potent and selective competitive inhibitor of aromatase (ki = 35 nm). drugs with dual serm and ai activity, such as 4'-hydroxynorendoxifen, have been developed from norendoxifen, and may have therapeutic potential as antiestrogens in the treatment of estrogen receptor-positive breast cancer. norendoxifenclinical dataother names4-hydroxy-n,n-didesmethyltamoxifenidentifiers iupac name 4--2-phenylbut-1-enyl]phenol cas number1217237-98-3 ypubchem cid68037237drugbankdbmet00963chemspider32817000unii51gjd354b5chemblchembl2386284chemical and physical dataformulac24h25no2molar mass359.469 g·mol−13d model (jsmol)interactive image smiles ccc(=c(c1ccc(cc1)o)c2ccc(cc2)occn)c3ccccc3 inchi inchi=1s/c24h25no2/c1-2-23(18-6-4-3-5-7-18)24(19-8-12-21(26)13-9-19)20-10-14-22(15-11-20)27-17-16-25/h3-15,26h,2,16-17,25h2,1h3key:ycqbltpgqsylhd-uhfffaoysa-n