Study On The Reaction Of Iron-catalyzed 2-Arylindoles To Synthesize Amines

Indole is an important class of N-containing heterocyclic compounds,which exists in many natural products and biologically active molecules.Studies have shown that indole derivatives have significantly biological activity and are widely used in the medical,fragrance and dye industries.At the same time,the indole materials are not only easy to be obtained,but also important synthetic intermediates and blocks in organic synthesis.The transformation of the indole skeleton has also attracted the interest of organic chemists.In this thesis,we mainly studied the synthesis of amine compounds by iron-catalyzed C-C/C-N bond cleavage with 2-arylindoles.This paper is divided into three parts:In the first part,2-aminobenzonitrile compounds were synthesized by a one-pot fashion of nitration and iron-catalyzed C-C cleavage of 2-arylindoles under mild conditions.The present method features wide substrate range,gram scalable preparations,an inexpensive iron(III)catalyst,environmental friendly,easily available raw materials and novel C-C bond cleavage of indoles.It is worth noting that 2-aminobenzonitrile easily underwent annulations under acidic conditions to form 2-aryl benzoxazinones.In the second part,synthesis of 3-aminoindole compounds by dehydrogenation cross-coupling reaction of 2-arylindoles with benzylamines under iron(III)-catalyzed was developed.The effects of different temperatures,solvents,metal catalysts and other conditions on the reaction were investigated.Experimental investigations have found that the reaction was compatible with either 2-arylindoles or benzylamines bearing electron-donating or electron-withdrawing groups.Most of the 3-aminoindole compounds were obtained in good to excellent yields.In the third part,synthesis of quinoxaline derivatives was developed by iron-catalyzed reaction of 2-aryindoles and o-diarylamines.We optimized the conditions of solvent,temperature and catalyst for the reaction,and study the applicability of the substrate scope.It was found that the reaction had the advantages of simple operation,good compatibility of functional groups and good yields.This strategy not only provides a method for the efficient synthesis of quinoxaline derivatives,but also lays a foundation for the biological activity of quinoxalines.