Norethindrone; (8R,9S,10R,13S,14S,17R)-17-ethynyl-17-hydroxy-13-methyl-1,2,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-3H-cyclopenta[a]phenanthren-3-one; CAS No.: 68-22-4; (8R,9S,10R,13S,14S,17R)-17-ethynyl-17-hydroxy-13-methyl-1,2,6,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-3H-cyclopenta[a]phenanthren-3-one (CAS 68-22-4) underscores ChemShuttle s role in pharma building blocks for steroidal alkynes. This ethynyl-testosterone (CAS 68-22-4) serves as a pharma building block in androgen receptor modulator design. As a worldwide chemical supplier, ChemShuttle delivers CAS 68-22-4 with documentation for hormone research.