pentagestrone pentagestrone pentagestrone (inn), also known as 17α-hydroxyprogesterone 3-cyclopentyl enol ether, is a steroidal progestin of the 17α-hydroxyprogesterone group that was never marketed. an acetate ester, pentagestrone acetate (gestovis, gestovister), has been marketed for clinical use. pentagestrone was described in the literature in 1960. pentagestroneclinical dataother names17α-hydroxyprogesterone 3-cyclopentyl enol etherdrug classprogestogen etheridentifiers iupac name 1-phenanthren-17-yl]ethanone cas number7001-56-1pubchem cid3047827chemspider2310139uniil34yl185wlchemblchembl2104801chemical and physical dataformulac26h38o3molar mass398.587 g·mol−13d model (jsmol)interactive image smiles cc(=o)c1(ccc2c1(ccc3c2cc=c4c3(ccc(=c4)oc5cccc5)c)c)o inchi inchi=1s/c26h38o3/c1-17(27)26(28)15-12-23-21-9-8-18-16-20(29-19-6-4-5-7-19)10-13-24(18,2)22(21)11-14-25(23,26)3/h8,16,19,21-23,28h,4-7,9-15h2,1-3h3/t21-,22+,23+,24+,25+,26+/m1/s1key:rbfqpffcdlxwqk-uxucurbisa-n