Research Of The Total Synthesis Of Natural Products Podophyllotoxin And Helioxanthin

In this thesis, the two natural products Podophyllotoxin and Helioxanthin were total synthesized, the key step was Heck Domino reaction and Heck reaction respectively. The determined Domino step was obtained via successes intermolecular Pd-catalyzed Domino-Heck reactions.Chapter one: study on the recent progress of Podophyllotoxin biological activity.The attention of pharmacists for lignans in general and Podophyllotoxin in particular is due to the pronounced cytotoxic activity of a number of these compounds. Several plant species accumulate the 2,7’-cyclolignans Podophyllotoxin, which is used as the starting compound for the production of three semi synthetic anticancer drugs. The drive for a large number of scientists to search for alternative sources of Podophyllotoxin. The chemical synthesis of Podophyllotoxin is possible but largely hampered by the complicated stereo chemical ring closure necessary to attain this compound. Synthetic production therefore only yields restricted quantities at high costs. An ideal resource would be a fast growing, easy to cultivate plant, with a high lignan content. Preferably in the aerial parts. A biotechnological approach, aimed at expressing lignin synthetic enzymes in an efficient host cell, might also solve the supply problem.Chapter two: Synthesis Podophyllotoxin by Palladium-Catalyzed Domino Heck Reaction.Lately, synthesis of Podophyllotoxin used different methods, Pd–catalysts Domino Heck reaction is adopted here. In the sample area of one-pot multistep processes is witnessing a large growth of attention and a resultant rapid increase. Pd-catalyzed Domino Heck reaction has to the best of our knowledge, not been put forward yet. According to Tietze Domino reaction is defined as a process that involving two or more bond-forming transformations which take place under the same reaction conditions without additional reagents and catalysts, and in which the subsequent reactions result as a consequence of the functionality formed in the previous step.The Palladium catalyzed Domino Heck reaction transformations have seen a spectacular development over the past few years indeed, because palladium has the advantage of being compatible with many functional groups; it constitutes an ideal catalyst for Domino reactions.The Heck Domino reaction has proven to be exceptionally useful. And Heck Domino reaction has newly been the focus of attention in both the academic and industrial community.Chapter three: Synthesis Helioxanthin by Metal-Palladium Heck Reactions.In the earlier studies, we have discovered a few compounds with comparable antiviral activity to the parent compound. This research focus on the reduction of costs of these reactions by the creation of highly active catalysts, and on the reduction of waste by developing a halidefree Heck reaction based on using aromatic anhydrides as arylating factors.The palladiumcatalyzed alkylation and arylation of unsaturated molecules using organmercury reagents as the provenance of the transferred alkyl or aryl group. In the effort to explore various anti-HBV agents, Helioxanthin analogues are used for inspiration. The strategy is to identify essential structural motifs that enable a Helioxanthin analogue to block HBV production. The key structural elements will then combine on the arylnaphthalene scaffold to produce more potent Helioxanthin derivatives.Chapter four: Results of the Experiments Podophyllotoxin and Helioxanthin synthesis.Results of the experimental Part of the literature considered the basis of the experimental Podophyllotoxin, and Helioxanthin with the Structural characteristics of a simple pepper aldehyde as the starting material, α,β-unsaturated carbonyl compounds are selected by lithium aluminum hydrogen reduction reactions as a key steps to have the Knoevenagel condensation.Peracetic acid epoxy between chlorine and alkaline hydrogen peroxide epoxy. DCC condensation esterification reaction of the Podophyllotoxin. Palladium-Catalyzed alkylation and arylation of unsaturated molecules using organomercury reagents as the provenance of the transferred alkyl or aryl group.