FRAMSTAELLNING AV SAOSOM 5ALFA-REDUKTAS-INHIBITORER ANVAENDBARA 4-AZA-17-SUBSTITUERAD-5ALFA-ANDROSTAN-3-ONER

A process for preparing 17 beta -carboxy-4-androsten-3-ones comprising the steps of (1) reacting a 17 beta -(1-ketoethyl)-5-androsten-3-ol, for example, pregnenolene, with pyridine and iodine to form a pyridinium iodide compound; (2) reacting the pyridinium iodide compound with alkali metal methoxide in methanol to form a methyl-5-androsten-3-ol-17 beta carboxylate; (3) oxidizing the product of Step (2) preferably with aluminum isopropoxide to form methyl-4-androsten-3-one-17 beta -carboxylate; and (4) hydrolyzing the product of Step (3) to the corresponding 17 beta -carboxylic acid, salt, or ester. The 17 beta -carboxy-4-androsten-3-ones are useful as intermediates for preparation of N-substituted-17 beta -carbamoylandrost-4-en-3-one and 4-aza-17 beta -substituted-5 alpha -androstan-3-one 5 alpha reductase inhibitors.