Isolation and identification of novel impurities in spironolactone

Three known and five new steroidal compounds as impurities in spironolactone were isolated from the enriched mother liquor by using various chromatographic methods. Their structures were elucidated by spectrometric analysis. New compounds were characterized as 3-(3,3-dimethoxy-5α,7α-epidithio-17β-hydroxy-4-androstan-17α-yl) propionic acid γ-lactone (6); 3-(3-oxo-7α-acetylthio-6β,17β-dihydroxy-4-androsten-17α-yl) propionic acid γ-lactone (7); 7α-acetylthio-17β-20-isopropylidendioxy-21-nor-17α-pregn-4-en-3-one (8); 7α-acetylthio-3-oxo-pregna-4,17(20)i-dien-22-oic acid methyl ester (9) and 7α-acetylthio-17-methyl-18-nor-androsta-4-en-3-one (10).