|Title:||Electro-Organic Synthesis of Some Natural Product Analogues|
|???metadata.dc.contributor.*???:||Dr. Tesfaye Biftu|
|Publisher:||Addis Ababa University|
|Abstract:||In this project an attempt was made to prepare lignans by oxidative and reductive coupling of the a-enolates and a-bromo derivatives of substituted propiophenones respectively. Propiophenone derivatives were prepared by the addition of ethylmagnesiuin iodide to substituted benzaldehydes followed by oxidation of the intermediate alcohols with Jones’ reagent . The a-bromo propiophenone derivatives were prepared by treating the ketones obtained with bromine in chloroform solution. Prior to preparative electrolysis of the a-enolates and a-bromo derivatives, the working potentials were determined by cyclic voltammetry and DC polarography. It was found out that the carbonyl functional group was reduced at a potential greater than -1.9V and C-Br bond it was cleaved to the corresponding free radical or carbanion in the potential range of -0.2V to -1.4V. Preparative electrolysis of 3,4-methylenedioxypropiophenone in methanol containing, sodium methoxide and p o t a - ssium iodide at 1,05V (divided cell) gave the a-hydroxypropicphenone derivatives. The methyl ether propiophenone derivatives were also obtained when the ketones were electrolyzed at various working potentials in qqueousmethanol medium containing the electrolytes sodium hydroxide and potassium iodide. Exhaustive preparative electrolysis of the a-bromo-3,4'-dimethoxynropiophenone derivative at “1.7V vs SCE usinp platinum electrode (divided cell)pave a lipnan of the 1,4-diaroylbutane derivatives.|
|Description:||A Thesis Submitted to the School of Graduate Studies in Partial Fulfilment of the Requirement for the Degree of Master of Science in Chemistry|
|Appears in Collections:||Thesis - Chemistry|
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