title: Synthesis of the allylic gonadal steroids, 3 alpha-hydroxy-4-pregnen-20-one and 3 alpha-hydroxy-4-androsten-17-one, and of 3 alpha-hydroxy-5 alpha-pregnan-20-one.
abstract: A method for the convenient synthesis of the recently isolated allylic gonadal steroids, 3 alpha-hydroxy-4-pregnen-20-one (3 alpha-dihydroprogesterone; 3 alpha-DHP) and 3 alpha-hydroxy-4-androsten-17-one (3 alpha-HA), was developed using 4-pregnene-3,20-dione (progesterone) and 4-androstene-3,17-dione as substrates and potassium trisiamylborohydride (KS-Selectride) as reducing agent. Similar reactions were also used for the reduction of 5 alpha-pregnane-3,20-dione to 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha-HP). The yields were about 15%, 50%, and greater than 90% for 3 alpha-DHP, 3 alpha-HA and 3 alpha-HP, respectively. Structures of the products, including the 3 beta-isomers and the 17 alpha-epimer, formed in these reactions were determined by NMR and mass spectroscopic methods.
mesh_terms: D000735:Androstenedione; D000738:Androsterone / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D010084:Oxidation-Reduction; D011278:Pregnanes / Q000138:chemical synthesis*; D011280:Pregnanolone / Q000138:chemical synthesis*; D011374:Progesterone
chemical_list: D011278:Pregnanes; C047746:3-hydroxy-4-androsten-17-one; D000735:Androstenedione; D011374:Progesterone; D011280:Pregnanolone; D000738:Androsterone