Benzothiazole Derivatives Synthesis And Metal Complexes Catalyzed Carbonylation Reaction

Carbonylation is a transition metal-catalyzed reaction using carbon monoxide as a carbonyl source of aldehydes,ketones,carboxylic acids and their derivatives.Carbonylation has been widely used in organic synthetic chemistry.The catalytic process of carbonylation has become an attractive subject in organic chemistry and coordination chemistry.In this thesis,benzothiazole derivatives have been synthesized,and the complexes of cobalt and rhodium have also been prepared as catalysts for carbonylation.The capabilities in carbonylation have been investigated.The studies are significant to propose the synthetic methodology of benzothiazole derivatives,broaden the application of the metal complexes of benzothiazoles.It is practical value of the research in preparation of phenylacetic acid from metal-catalyized carbonylation.The thesis consists of four chapters.The main contributions are listed as follows.1.Eleven benzothiazole derivatives were synthesized using 2-aminobenzothiazole as raw material,which are the derivatives of benzothiazole-2-carboxylic acid,2-(4,5-dihydro-2-thiazolyl)benzothiazole and 2-(2-benzothiazolyl)-4,5-dihydro-(4S)-4-thiazolecarboxylic acid.2.The synthesis conditions of four derivatives of 2-cyanobenzothiazole were studied and optimized.Benzothiazole-2-carboxylic acids were synthesized in a good yield with hydrolyzation of 2-cyanobenzothiazoles in alkalic conditions.A novel method of synthesis of benzothiazole-2-carboxylic acids was proposed.3.The derivatives of 2-(4,5-dihydro-2-thiazolyl)benzothiazole were synthesized in alkalic conditions.Two single crystals were obtained,and the supramolecular structures were determined by X-ray diffraction.4.Eighteen novel cobalt and rhodium complexes of the ligands of benzothiazole-2-carboxylic acids,2-(4,5-dihydro-2-thiazolyl)benzothiazoles and 2-(2-benzothiazolyl)-4,5-dihydro-(4S)-4-thiazolecarboxylic acids were synthesized and characterized.5.The single-crystal structures of complexes bis(N,N-Dimethylformamide)bis(6-methoxyl benzothiazole-2-carboxylato)cobalt(â…¡) and bis[2-(4,5-dihydro-2-thiazolyl)-6-methoxyl- benzothiazole]dichlorocobalt(â…¡) were determined by X-ray diffraction.The single-crystal structural analysis revealed that the complex of bis(N,N-Dimethylformamide)bis-(6-methoxylbenzothiazole-2-carboxylato)cobalt(â…¡)was a distorted octahedron conformation, and the complex of bis[2-(4,5-dihydro-2-thiazolyl)-6-methoxylbenzothiazole]-dichlorocobalt (â…¡) was distorted pyramid conformation.6.The synthesis of phenylacetic acid from the carbonylation of benzyl chlorine catalyzed by cobalt complexes was studied.The effects of phase transfer catalysts,solvents,reaction temperature and the concentration of alkali on the reactions were investigated.The use of abandoned carbon monoxide from Nitrogenous Fertilizer Plant and the recycling of the catalysts were studied.The research indicated that the yield of phenylacetic acid in this catalytic system was slightly higher than in a similar one.The technology has been applied for national invention patent.7.The synthesis of phenylacetic acid from the carbonylation of benzyl chlorine catalyzed by rhodium complexes was studied.The yield of phenylacetic acid was more than 90%.The purity was 99%.