Method for preparing 7 beta-hydroxydehydroepiandrosterone from dehydroepiandrosterone and application of 7 beta-hydroxydehydroepiandrosterone

The invention discloses a method for preparing 7 beta-hydroxyl dehydroepiandrosterone by using dehydroepiandrosterone, which is characterized in that dehydroepiandrosterone is used as a raw material, and the 7 beta-hydroxyl dehydroepiandrosterone is prepared by five steps of 17-cyanation, 3, 17-acyl protection, 7-oxidation, 7-reduction and hydrolysis. According to the preparation method, simple and easily available DHEA is taken as a raw material, 17-position carbonyl is protected through cyanation, 3 and 17-position hydroxyl is protected through acyl, 7-position carbonyl is introduced through oxidation, then the 7-position carbonyl is reduced into 7 beta-hydroxyl through selective reduction reaction, and finally the 7 beta-hydroxyl dehydroepiandrosterone is prepared through hydrolysis. According to the preparation method disclosed by the invention, chemical reagents and catalysts with relatively high cost do not need to be used, and the defects of low yield, difficulty in purification and the like caused by