Synthesis Of Polyhydroxy Sterol 25(R)-Isospirost-5-En-2 Beta,3 Alpha,19-Triol

The polyhydroxy sterol 25(R)-isospirost-5-en-2 beta,3 alpha,19-triol was synthesized from diosgenin by seven steps including tosylation, oxidative addition with N-bromo-succinimide (NBS), far-way oxidation with Pb(OAc)(4), elimination, oxidation of m-chloroperbenzonic acid (mCPBA) and reduction with Zn powder. The structures of the intermediates and the target product were elucidated by IR, H-1 NMR, C-13 NMR, MS spectra and elemental analysis.