Improved Syntheses of Epristeride, a Potent Human 5α-Reductase Inhibitor

Article abstract of DOI:10.1021/jo00099a031

Two improved syntheses of a potent human 5α-reductase inhibitor, epristeride, SK&F 105657, are described.The first synthesis starts from methyl 3-oxoandrost-4-ene-17β-carboxylate (1), which is converted to epristeride (5) in four synthetic steps in 44percent overall yield.The second synthesis starts from commercially available 3-oxoandrost-4-en-17β-carboxylic acid (7), which is converted to epristeride (5) in two synthetic steps in 63percent overall yield.Both syntheses are suitable for large scale production and have been employed to produce kilograms supplies of epristeride in high purity.