Process for preparing 17.beta.-carboxy-5-androsten-3-ones

A method for preparing a 17.beta.-carboxy-4-androsten-3-one having the formula:

• ##STR3## where R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are the same or different and are hydrogen or lower alkyl;
• R.sup.7 is hydrogen or cyano;
• M is hydrogen, lower alkyl, or alkali metal;
• Z is CH--R.sup.9 where R.sup.9 is hydrogen, .alpha.-fluoro, or .alpha.-lower alkyl;
• and the dotted line between positions 1 and 2 represents the possibility of a single bond when Z is CH--R.sup.9 and a double bond when Z is C--R.sup.9 ;
• comprising the steps of
• (1) reacting a 17.beta.-(1-ketoethy)-5-androsten-3-ol 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 5-androsten-3-ol to form methyl-4-androsten-3-one-17.beta.-carboxylate;
• and
• (4) hydrolyzing the methyl-17.beta.-carboxylate to the corresponding 17.beta.-carboxylic acid.