Synthesis Of 2-substituted Benzothiazole From Aromatic Amine Or O-Aminothiophenol

Benzothiazole derivatives are widely used in pesticides,pharmaceuticals and other fields,and are also the core skeleton for constructing many functional materials and natural products.As increasing of our environmental,economic,and sustainable requirements for organic synthesis,developing greener,more efficient methods for the synthesis of benzothiazole is becoming more urgent.Studies on the synthesis of benzothiazole have been reported in many literatures.It has always been the goal for scientific researchers to synthesize these compounds by using simple,cheap and readily available raw materials under transition metal-free conditions.In this paper,based on the environment-friendly synthesis of benzothiazole derivatives,a series of benzothiazole derivatives were synthesized using aniline and o-aminothiophenol as the starting materials without transition metal catalyst.There is no need to add transition metal catalysis which can not only reduce the reaction cost,but also avoid the pollution coming from metal.The study is as follows:1.Developing a simple,mild and efficient synthesis method for 2-benzyl benzothiazole using o-aminothiophenol,styrene or phenylacetylene as raw materials.Inexpensive elemental sulfur was used as the promoter without transition metal and considerable yield were obtained in this reaction system.Based on above research,the further oxidation of 2-potenylbenzothiazole was achieved by"one-pot,two-step"method and 2-benzoylbenzothiazole was successfully synthesized.Provide a new approach for the synthesis of heterocyclic compounds in the absence of transition metal.2.A method for the three-component synthesis of 2-quinolinyl benzothiazole was developed using aniline,2-methylquinoline and elemental sulfur as raw materials.In this method,ammonium iodide as an additive,the aromatic methyl group was activated and further construct heterocyclic compound without transition metal catalysts,which provide a simple and novel approach for synthesizing heterocyclic functional molecule.