Study On The Synthetic Methodology Of Isatin From Indole Oxidized By I₂O₅

Isatin is a purple natural product,existing in a variety of animals and plants,and is also a very important bioactive substance.The isatin and isatin derivatives exhibit a wide range of pharmacological properties and have been studied as anti-cancer,anti-inflammatory,anti-HIV,anticonvulsant and antimicrobial agents.In addition,isatin can be applied as a multi-functional intermediate for the construction of various important heterocyclic compounds.A variety of chemical reactions can occur on nitrogen atoms,dicarbonyl and benzene ring.In particular,isatin can prepare many biological compounds,especially chiral spiro compounds.At present,the researches on the synthetic strategies and applications of isatin and its derivatives are very active,and preparing this important structural unit has also aroused great concern of synthetic chemists.Nevertheless,there is still a need to develop more practical,environmentally friendly and efficient access to isatin.In this paper,the application and the strategies of preparing isatin were discussed.On the basis of known synthetic strategies,we have developed a method for synthesizing isatin.The paper mainly includes the following three parts:In the first chapter,we summarized the recent researches on the application and synthesis of isatin.The structure and properties of iodine reagent and its application in the synthesis of isatin were studied in detail.In the second chapter,a simple and efficient method of obtaining isatin with indole as raw material and inorganic iodine pentoxide as oxidant has been developed.The impact of temperature,the amount of oxidant,the solvent and acid or base on the reaction were investigated,and the optimum reaction conditions were screened out.Under the optimum reaction conditions,the scope of indole substrates was also extended.Most of the target product can be obtained in medium to excellent yield.The scale of the reaction of N-methyl indole was successfully achieved.Advantages of this reaction can concluded as follow:readily available raw materials,non-toxic oxidants,simple operation,high yield,the short reaction time.In the third chapter,present researches on bioactivity and synthesis of tryptanthrin are described.Based on strategies of tryptanthrin and its derivatives,the synthesis of isatoic acid anhydride from isatin was carried out.The addition reaction of isatin and isatoic anhydride was realized to obtain the target product tryptophan in the alkaline solution.Finally,the tryptanthrin was applied to prepare natural products with various biological activities.