3-Oxo-4-aza-11a-methoxy-5a-androst-1-ene-17B-carboxylic Acid Methyl Ester is an intermediate in the synthesis of Finasteride (F342000), an inhibitor of 5a-reductase, the enzyme which converts testosterone to the more potent androgen, 5a-dihydrotestosterone.Solubility:Ethyl Acetate, Methanol