penmesterol penmesterol penmesterol (inn) (brand names pandrocine, testopan; former developmental code name rp-12222), or penmestrol, also known as 17α-methyltestosterone 3-cyclopentyl enol ether, is a synthetic, orally active anabolic-androgenic steroid (aas) that was developed in the early 1960s. it is the 3-cyclopentyl enol ether of methyltestosterone. penmesterolclinical datatrade namespandocrine; testopanother namesrp-12222; 17α-methyltestosterone 3-cyclopentyl enol etherroutes ofadministrationby mouthidentifiers iupac name (8r,9s,10r,13s,14s,17s)-3-cyclopentyloxy-10,13,17-trimethyl-1,2,7,8,9,11,12,14,15,16-decahydrocyclopentaphenanthren-17-ol cas number67-81-2pubchem cid20054971chemspider16735903uniid5f29u03hmchemblchembl2104849echa infocard100.000.609 chemical and physical dataformulac25h38o2molar mass370.577 g·mol−13d model (jsmol)interactive image smiles c12ccc(=cc1=cc32cc4(3cc4(c)o)c)oc5cccc5 inchi inchi=1s/c25h38o2/c1-23-13-10-19(27-18-6-4-5-7-18)16-17(23)8-9-20-21(23)11-14-24(2)22(20)12-15-25(24,3)26/h8,16,18,20-22,26h,4-7,9-15h2,1-3h3/t20-,21+,22+,23+,24+,25+/m1/s1key:zubdxghkaamaaa-rfxjpfprsa-n