STRUCTURAL BIOCHEMISTRY: II. SYNTHESIS OF 3β-HYDROXY-17β (L-PROLYL-L-PROLYL)AMINO-5α-ANDROSTANE

A practical synthetic route to 3β-hydroxy-17β-amino-5α-androstane (III) was developed and the configuration of the amine substituent established by proton magnetic resonance studies. Condensing amine III with carbobenzoxy-L-proline by means of Woodward's reagent K led to proline derivative IVa. Steroidal peptide Vb was readily prepared by first removing the protecting group from amide IVa by palladium-catalyzed hydrogenolysis and then repeating the peptide-forming and hydrogenation steps. Protection of the 3β-hydroxy group proved to be unnecessary, and the presently reported approach to steroidal peptides proved to be reliable and useful.