Novel synthesis of (24R,6E)-24-ethylcholest-6-hydroxyimino-4-en-3-one, a steroidal oxime fromCinachyrella spp. sponges

(24R,6E)-24-ethylcholest-6-hydroxyimino-4-en-3-one (1), which was isolated previously fromCinachyrella spp. sponges, is synthesized in five steps from -sitosterol in 30% overall yield.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Belarus, 220141, Minsk, ul. Akad. Kuprevicha, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 149–151, March–April, 2000.