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Synthesis Of Nitrogen-containing Heterocyclic Unsymmetric Urea By Selenium-catalyzed Carbonylation

Posted on:2006-03-02Degree:DoctorType:Dissertation
Country:ChinaCandidate:J Z ChenFull Text:PDF
GTID:1101360155952334Subject:Organic Chemistry
Abstract/Summary:PDF Full Text Request
Urea can be synthesized with Se/CO catalytic system by one-pot oxidative-reductive carbonylation of nitrobenzene. The purpose of this theme is to study thescope and limitation of this new catalytic system. We have investigated thereductive carbonylation of nitropyridine with selenium catalyst. A series of newunsymmetrical dipyridylurea derivatives have been acquired for the first time bythis method.Selenium catalytic acylation of nitropyridine has also been studied withtriethylamine and 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) as co-catalysts, andbenzamide as co-reagent.Carbonylation reaction of nitrobenzene and aminopyrimidine has beeninvestigated systematically.The catalyst reusability has been carried out, which indicates the catalystexhibits the same activity and selectivity during its reusability.The reaction phenomena are explained by Reaction-process Phase-transferCatalysis. That is, the reaction system changes from heterogeneous tohomogeneous phase during the reaction, and recycles to the heterogeneous phaseafter the reaction. Therefore, this catalytic system possesses advantages of bothhomogeneous and heterogeneous catalysis.The selective reduction of nitrobenzene to N-hydroxybenzenamine has beenstudied with sodium borohydride as reductive reagent instead of carbonmonoxide.
Keywords/Search Tags:Selenium, Carbonylation, Dipyridylurea, Pyrimidylurea, Reaction-process Phase-transfer Catalysis, N-Hydroxybenzenamine
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