Synthesis of (22E,24R)-5a-ergosta-2,7,22-trien-6-one

The synthesis of the 5a-hydroxy-2,7,22-trien-6-one (3) has been achieved by the mesylation of ergosterol (1a) and oxidation of the resulting mesylate (1b) with chronic acid to 3,5a-dihydroxy-7,22-dien-6-one 3-mesylate, followed by elimination.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141, Minsk, ul. Akad. Kuprevicha. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 100–102, January–February, 1999.