Polyhydroxy Sterol 25 (r) - Lo-steroidal Ring - 5 - En-2¦Â, 3a, 19 - Triol Synthesis

The sterols exhibited potential bioactivities such as antitumor,cytotoxic, antibacterial, antifouling, antiflammation and anticardiovascular disease activity. It is a class of promising prospects for the development of new drug compounds. Later people found sterols also play a very important role in the nervous system. The discovery of neurosteroids opens up a new field in the brain and shows more and more important because of many evidences indicates that neuroactive steroids play an important role in brain function, especially in the higher brain function such as learning and memory, cognitive, emotional. In this paper, the main contents and the results are as follows:(1)We have the basis of the structure-activity relationship of the neuroprotective sterols,sowe decided to synthesis the polyhydroxy sterol 25(R)-spirost-5-en-2β, 3α, 19-triol with aview to the application of neural protection.(2) We designed the route of synthesising the polyhydroxy sterol 25(R)- spirost-5-en-2β, 3α, 19-triol. It was synthesized from cheap diosgenin by seven steps which contained sulfuryl reaction, oxidative addition reaction with NBS, far-way oxidation of Pb(OAc)₄, elimination, oxiddition of mCPBA and reduction with Zn powder.(3) We described the steps of synthesising 25(R)-spirost-5-en-2β,3α, 19-triol detailedly. Their structures were elucidated by IR, ¹HNMR ¹³CNMR, MS and EA. Mainly through ¹HNMR, ¹³CNMR MS analysis confirmed the details of various intermediates and 25(R)-spirost-5-en-2β,3α,19-triol. NOESY confirmed that the stucture of target product is 2β, 3αconfiguration.(4)We confirmed that another polyhydroxysterol is 25(R)-spirost-5α-H-2β,3α, 19-triol.(5)We get the conclusion that there were only 2, 3 epoxy pen-ring and 6,19- oxygen bridgestructure was not changed in the conditions existing perchlorate.The spirost rings havenot changed in this seven-step reaction conditions.