Synonyms: (6alpha)-6-Methylpregn-4-ene-3,11,20-trione;6.alpha.-Methyl-11-oxoprogesterone;6alpha-Methyl-11-oxoprogesterone;6A-METHYL-PREGN-4-ENE-3,11,20-TRIONE;Pregn-4-ene-3,11,20-trione, 6.alpha.-methyl-;Pregn-4-ene-3,11,20-trione, 6-methyl-, (6.alpha.)-;pregn-4-ene-3,11,20-trione, 6-methyl-, (6alpha)-;Progesterone, 6.alpha.-methyl-11-oxo-;Progesterone, 6alpha-methyl-11-oxo-