Investigation On The Synthesis Of Indenopyrrole,2-Aminonaphthalene And 2-Aminoquinazoline Derivatives Involving Isocyanides

Isocyanides(-NC)are a class of compounds containing special bond structure,which is easily to react with nucleophiles,electrophiles and radicals,showing strong ability of metal coordination.As an important C1 and N1 synthon,isocyanide is highly favored by synthetic workers with the advantages of simple operation,high bond-forming efficiency,good reaction selectivity,which is widely used in the construction of natural products,drug molecules and nitrogenous compounds with potential biological activities.On the other hand,as an important class of organic molecules,nitrogenous compounds are widespread present in nature,which plays an important role in the fields of medicine,pesticides,dyes and functional materials.Therefore,it is very valuable to develop green and high-efficient strategies to realize the construction method of nitrogenous compounds involving isocyanides.In this regard,transition metals or metal-free catalyzed tandem cyclization reactions involving isocyanides have been developed using cheap and available substrates as starting materials herein,and different types of nitrogen-containing compounds have been constructed under simple and mild reaction conditions.Furthermore,the antitumor activities or optical properties of representative target products are preliminarily investigated.The specific research content is as follows:(1)We researched a new method for synthesizing indeno[2,1-b]pyrroles derivatives from 2-(2-ethynylphenyl)acetonitriles via the orderly insertion of two molecules of isocyanide under palladium-catalyzed conditions.The present work features advantages including molecular oxygen as the sole oxidant,mild conditions,high selectivity and atom economy.Notably,this transformation involves the formation of three C-C and one C-N bonds without isolating the intermediate.The key to the success of this protocol is construction of new C-C and C-N bonds via the orderly insertion of isocyanides.(2)We researched a palladium-catalyzed tandem cyclization reactions of 2-(2-vinylarene)acetonitriles with isocyanides to synthesize a series of 2-aminonaphthalene derivatives.Taking into account the combination of some desirable features,such as easily available starting materials,facile operation and good functional group tolerance.Moreover,the antitumor activity of the target compounds was screened by MTT method,and the results showed that compounds 3-3ea,3-3ma and 3-3qb exhibited good antitumor activity.Further studies on apoptosis showed that these three compounds could induce apoptosis of PC-3 cells.(3)We researched an iodine-catalyzed o-aminobenzophenone oximes and isocyanides for the construction of 2-aminoquinazoline derivatives.This reaction proceeded smoothly under mild conditions with high yield and broad substrate scope.In addition,the optical investigation of compounds 4-3ja,4-3qa,4-3ra,4-3sa and 4-3ta showed that these five compounds exhibited good ultraviolet absorption and fluorescence properties.