Studied On Synthesis Of 2,4-Diarylthiazole And 1-Benzyl-2,4-Diarylimidazole

Thiazole is a five-membered heterocyclic compound containing sulfur and nitrogen atoms that can act as a basic active structural skeleton in natural products.Several studies have documented that it has anti-inflammatory,antibacterial,anti-cancer and other positive effects when it has been applied in the field of materials ands agricultural production.The prevalent usage of the thiazole in industry indicates a further investigation on developing an that an efficient green method for thiazole synthesis for saving energy.Imidazole is a kind of five-membered heterocyclic compound containing two nitrogen atoms.It is commonly present in natural products and exhibits the characteristics of stable structure and high activity.It can be employed in the synthesis of pharmaceutical intermediates and is applicable to electrochemistry and photochemistry.Polysubstituted imidazole has drawn considerable attention from the scientific community because if its broader application prospect and research value.In the first chapter of the paper,several synthetic methods of thiazole have been analyzed and summarized in this thesis.These methods have been classified based on their raw materials 1)Isothiocyanate;2)Thiourea;3)Thioamide;4)Disulfide;5)Dithioester;6)Other materials.Following,different strategies for the synthesis of imidazoles have also been summarized and categorized on their raw materials:1)Carbonyl compounds;2)Acetylene compounds;3)Amidine compounds;4)Nitrile or isonitrile compounds;5)Amine compounds.In the second chapter,this thesis has reported on a mild chemical synthesis of 2,4-diarylthiazole by the reaction of sulfoxonium ylides with benzothioamide under palladium catalysis.This reaction avoid the use of halogen-containing atomic reagents and diazo compounds that would reduce the environmental damage,the risk,and the cost.Furthermore,this synthesis has a good chemical selectivity and wide substrate adaptability,which obtains the high yield thiazole product of 97%.In the third chapter,a method of synthesizing 1-benzyl-2,4-diarylimidazole has been reported on using 2-pyridyl hydrazones and benzylamine catalyzed by I₂/CuI based on the literature.Compared with a traditional synthesis of polysubstituted imidazole,the use of I₂/CuI catalytic,replacing the rare metal catalyst,can obtain high yield of substitutive products（up to 85%）.This study provides a new experimental method for the synthesis of 1,2,4-triimidazole derivatives.