3 - Carbonyl -10 - Demethylation -12 - Methoxy -13 - Methyl Podocarpus Alkane Synthesis Research

In this thesis, synthesis of intermediate of terpenoids and steroids using methylation reaction were reviewed. It contained reaction time, base, product. At the same time, product and its yield were also reported.Total synthesis of 3-ketone-10-demethyl-12-methoxy-13-met- hylpodocarpane was expored. 1, 3-cyclohexanedione as starting material, constructed the A ring followed by methylated and carbonyl was protected. 4-bromophenol introduced aldohydle to phenyl ring by Reimer-Tie-mann reaction, then constructed C ring synthon followed by reduction, phenolhydroxyl protection. A ring synthon and C ring synthon after witting reaction, coupling, closing, and deprotec-tion synthesized the aim product. In order to improve the low yield of C ring synthon we amended the synthesis method though constructing the C ring synthon from o-cresol by phenol hydroxyl protection, p-brominated, Wittg reaction. Then coupling with A ring synthon, closing, deprotection, the aim product was synthesized finally. By the first method of construct the benzyl, the yield of the reduction reaction is low. However, c- hoosing o-cresol to construct the brominate product, the yield was raised to 90%.During the experiment, the related intermediate and the structure of products was confirmed by IR spectrum, ~1h NMR spectrometry, MS spectrometry.