The invention relates to a method for synthesizing ridge sha tan, which uses the 2-tert-butyl ketonic oxygen amido-3-nitro benzoate (I) and N-(trityl )-5-(4-morphine methylbiphenyll-2-group) tetrazolium (II) as raw material to do N-alkanisation reaction, protecting-released reaction, reduction reaction, ring-closed reaction and ester hydrolytic reaction. <0The protecting-released reaction can slough trityl and tert-butyl ketonic oxygen protect group in the lower aliphatic alcohol organic mixing solution. |