Studies On The Synthesis And Properties Of Novel N-substituted Benzene-1,2-diamines And Their Derivatives

The benzothiozoleaniline derivatives (BTA), such as thioflavin T and BTA-1, are a class of fluorescent dyes, which are used as the detection of amyloid fibrils. The previous research of our group demonstrated that 4-benzothiazol-2-yl-N1-phenylbenzene-1,2-diamine possessed special fluorescent properties and would promote the study on the new BTA fluorescent derivatives. In the other hand, as an important synthetic intermediate, the substituted 1,2-phenylenediamine could be utilized to synthesize the bioactive benzimidazole derivatives..The first part of this thesis focused on the development of new practical synthetic methodology for the novel 4-benzothiazol-2-yl-N1-phenylbenzene-1, 2-diamine. The second part of this thesis was the systematical study on the fluorescence properties and ions recognition of the 1,2-phenylenediamine. The third part of this thesis was to develop a new efficient microwave synthesis method for the 2-aminovinyl benzimidazoles with zirconium salts as the catalyst. The main research work is described as follow.1. The benzothiazole intermediate were efficiently prepared by the materials 4-chloro-3-nitrobenzoic and 2,2’-disulfanediyldianiline via reduction/cyclization in situ. Then, the triethylamine was used as base to promote the amination of halogenated aromatic hydrocarbon by aniline. Finally, the reduction by hydrazine hydrate could afford the product 4-benzothiazol-2-yl-N1-phenylbenzene-1,2-diamine. Further more, three kinds of benzimidazolines could be prepared via the condensation of 1,2-phenylenediamine with three ketones.2. The fluorescent preperties of the 1,2-phenylenediamine was systematically studied. The fluorescent spectra and fluorescence quantum yield of 4-benzothiazol-2-yl-N1-phenylbenzene-1,2-diamine are solvent dependent. The fluorescence of 4-benzothiazol-2-yl-N1-phenylbenzene-1,2-diamine weakens and the wavelength of its fluorescent spectrum becaome red-shift in the high polar solvent. According to the structure-effect relationship, benzothiazole group and 2 position substituent in the compound is crucial to the fluorescence of the dianilinet. The fluorescence lifetime of the compouds with two amino would be longer than the reference substance with one amino. Further more, the 1,2-phenylenediamine could selectively response to the copper ion in the CH3CN/H2O binary solvent mixture (CH3CN/H2O= 1/1, v/v). Additionally,4-benzothiazol-2-yl-N1-phenylbenzene-1,2-diamine exhibited selectivity toward the iron ion in methanol.3. Six kinds of N-arylated and N-dialkylated 3-aminoacroleins were synthesized. Cp2ZrCl2 was found to efficiently catalyze the synthesis of 2-aminovinyl benzimidazole in ethanal after the screening of metal catalysts and solvents. The oxidation of MnO2 was essential for the transformation from the intermediate to the product. Compared with traditional heat condition, microwave could obviously decrease the reaction time and improve the yield. Consquently, Treatment of the 1,2-phenylenediamines and N-arylated/N,N-dialkylated 3-aminoacroleins with Cp2ZrCl2 as the catalyst under microwave irradiation afforded series of 2-aminovinyl benzimidazoles.