High specific activity steroids: Pt. 2

The synthesis of the high specific activity (39 Ci/mmole) tritium labelled steroid norgestrel is described. A practical synthesis of the required substrate for tritium incorporation, 18-methyl-Δ9(11)-estradiol-3-methyl ether, was developed from norgestrel itself. Following reduction with carrier-free tritium gas, microscale conditions were employed for the conversion of the resulting labelled intermediate back to norgestrel-[9,11-3H], including a selective in situ projection of the A-ring ketone of 19-norandrost-4-ene-3,17-dione. (Author)