Studies on the Electrochemical Direct Oxidative Coupling of X-H Bonds and Synthesis of Azo Compounds

Author:Du Ke Si

Supervisor:huang jing mei

Database:Doctor

Degree Year:2019

Download:43

Pages:253

Size:12352K

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Using electrons as clean oxidants is a unique advantage of electrochemical methods,and it is also an important part of the green chemical industry.In recent years,electrochemical oxidative dehydrogenation has attracted great attention.This paper described the electrochemical Csp2-H/Csp3-H cross-dehydrogenation coupling reaction to synthesize bisindolylmethanes,the methylation of thiophenols/thiols(R-SH)to methyl sulfoxides and construction of N=N bonds by NH-NH oxidation.The thesis includes mainly the following three parts:The second chapter studies electrochemical synthesis of bisindolylmethanes from indoles and ethers.In this reaction,the N-methylindole radical cation was formed by the anode oxidation through single electron transfer.Then the radical cation reacted with THF to give the monoindolylated product,which could also be produced by the reaction of THF alkoxycarbenium ion with N-methylindole.Subsequently,Friedel-Craft alkylation of monoindolylated product with another molecule of indole afforded the cross-coupling target product.This reaction is easy to handle,and the starting material is cheap.Without any additional chemical oxidant,this process provides a new method for the synthesis of bisindolylmethanes.The third chapter studies the electrochemical synthesis of methyl sulfoxides from thiophenols/thiols and dimethyl sulfoxide.In this reaction,DMSO with low toxicity and low cost was used as a green-CH3 source,which reacted with-SH followed by oxidation to produce the sulfoxides.This raction proceeded high selectively,only a very small amount of sulfoxide continues to oxidize to sulfone.Both aromatic thiophenol and aliphatic mercaptan could afford the corresponding products in good yields.The fourth chapter studies the electrochemical dehydrogenation of hydrazines to azo compounds.In this reaction,ethanol was used as the solvent and the material was transformed into azo compound quantitatively.Only H2 was generated in theory,which met the requirements of green chemistry.Its synthetic value was well demonstrated by the highly efficient synthesis of symmetric and unsymmetric azo compounds through the gram scale experiment.