Studies On N-containing Heterocyclic Synthesis From O-Nitrochalcone Promoted By Base

Nitrogen-containing heterocyclic compounds are important scaffolds,which are widely existing in pharmaceuticals,natural products,agrochemicals as well as in functional materials.The synthesis of N-containing heterocyclic compounds has attracted great attention in organic synthetic field.Numerous methods have been developed on the synthesis of these kinds of compounds.Despite the great advances,efficient and practical synthetic methods which starts from readily accessible materials and performed under transition-metal free conditions are still highly appealing and remained unexploited.In this paper,the synthesis and application of indoles and quinoline N-oxides are reviewed.Based on the above research background,this thesis discusses the synthesis of 3-aminoindole,quinoline N-oxide heterocyclic compounds starting from readily available o-nitrochalcone derivatives under transition-metal free conditions.(1)An unprecedented method for constructing 3-aminoindoles using industrial-grade ammonia as "N" source was developed.o-Nitrochalcone was treated with aqueous ammonia or primary amines under basic condition via Michael addition andintramolecular cyclization reaction on nitro group,rendering 3-aminoindole compounds.The strategy features a wide range of substrates,good functional groups tolerance,simple operation and potential application in industry.The method can also be employed to synthesize COX-2 inhibitors and tubulin inhibitors.Furthermore,the reaction mechanism was discussed in detail with DFT calculations.(2)Umpolung of carbonyl group in o-nitrochalcones.Umpolung is a strategy which converts the property of an atom into the opposite one.There are very few reports on hydrazine hydrate to promote the umpolung of carbonyls under transition metal-free conditions.In this thesis,o-nitrochalcone was used as a template substrate to undertake umpolung of carbonyl group under basic conditions,rendering aza-allyl anion which further attacks the nitro group to form quinoline N-oxides.The strategy features transition-metal free,good functional-group tolerance,nitrogen as by-product,environment friendly as well as mild reaction.