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Preparation and Application of Fluorous Organocatalyst of Thiourea

Author: HuangYiBo
Tutor: CaiChun
School: Nanjing University of Technology and Engineering
Course: Chemical Engineering
Keywords: Organocatalyst fluorous thiourea fluorous solid phase extraction immobilizedcatalyst
CLC: O643.36
Type: PhD thesis
Year: 2012
Downloads: 108
Quote: 0
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Abstract


In this dissertation, N, N’-bis[3,5-bis(trifluoromethyl)phenyl]thiourea (Schreiner thiourea) was prepared by3,5-bis(trifluoromethyl)aniline and thiophosgene. And1-[4-(perfluorooctyl)phenyl]-3-phenylthiourea was prepared by perfluorooctyl aniline and phenyl isothiocyanate. A kind of polystyrene-supported fluorous thiourea catalyst was prepared by azido reaction, Click reaction with propargyl amine, adduction reaction with isothiocyanate using Merrifield resin as starting materials.The acetalization of aldehyde and ketone with1,2-ethandiol was investigated. The direct reductive amination of aromatic aldehyde, ketone and aromatic amine was researched under the organocatalytic reductive system of Schreiner thiourea and Hantzsch1,4-dihydropyridine. The reaction conditions such as temperature, catalyst loading, solvent and time were optimized in detail. The results showed that the aboved mentioned acetalization and reductive amination concerned with acid-sensitive substrates were effectively catalyzed by Schreiner thiourea as a kind of poor Lewis acid.The direct reductive amination of aldehyde and aromatic amine was studied using1-[4-(perfluorooctyl)phenyl]-3-phenylthiourea as catalyst,5A molecular sieve as dehydrating agent, under the solvent of CH2Cl2at the room temperature. Moreover, the Morita-Baylis-Hillman reaction of arylaldehydes with methyl acrylate has been developed by using this fluorous-tag organocatalyst and DABCO under the solvent of DMSO at room temperature. In addition, the chemoselective oxidation of sulfides in the presence of30%H2O2catalyzed by the fluorous thiourea was developed. Furthermore, the three component reaction of aromatic aldehyde, aromatic amine and cyclohexaone was studied catalyzed by the fluorous thiourea under the solvent of CH3OH. At the same time, some factors such as catalyst loading, solvent, substrate scope were explored in detail. The results showed that this kind of fluorous thiourea organocatalyst could effectively promote the aboved mentioned reactions. And the fluorous thiourea organocatalyst could be recycled for reuse using Fluorous Solid Phase Extraction method more than several times without the significant loss of catalytic activity.Finally, a kind of polystyrene-supported fluorous thiourea catalyst could be used to promote the reaction of1,3-dicarbonyl compounds and nitroolefins. And this immobilized organocatalyst could catalyze the preparation of hexahydroquinoline derivatives by the asymmetric Hantzsch reaction with aldehyde,5,5-dimethyl-1,3cyclohexandione. acetylacetic ether and ammonium acetate as starting materials. Moreover, the preparation of 9-aryl-1,8-dioxo-decahydroacridines were also catalyzed by this catalyst with the "one pot" method of5,5-dimethyl-1,3cyclohexandione, arylaldehyde, aromatic amine or ammonium acetate. Meanwhile, catalyst loading, solvent, temperature and subtrate scope were explored in detail. The results showed that this kind of PS immobilized thiourea could exhibit good performance in the above mentioned reactions. In addition, the immobilized catalyst could be recycled by simple filtration and washing. After several reuses, the catalytic activity did not decrease significantly.

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CLC: > Mathematical sciences and chemical > Chemistry > Physical Chemistry ( theoretical chemistry ),chemical physics > Chemical kinetics,catalysis > Catalytic > Catalyst
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