NHC-catalyzed Cascade Synthesis Of Nitrogen Heterocycles

This thesis is composed of four sections:In the first section, the applications of N-Heterocyclic carbenes (NHCs)-catalyzedcascade reactions in field of organocatalyst are reviewed.In the second section, we introduced a simple and flexible procedure for thesynthesis of a series of suitably functionalized1-substituted4-aryl-tetrahydroquinoline-2,5-diones. A wide range of potential biologically activequinoline derivatives for biomedical screening were obtained.In the third section, a new efficient approach to thetetrahydroimidazo[1,2-a]pyridines andtetrahydrobenzo[b]imidazo[1,2,3-ij][1,8]naphthyridines with biological significancewas successfully developed through NHC-catalyzed cascade C-C bond and C-N bondformation process. The alternative to the assembly of these multi-functionalizednitrogen bridgehead-fused heterocycles features mild conditions, moderate to highyields and operational simplicity.In the fourth section, a series of pyrazolinones were directly obtained fromphenylhydrazine hydrochloride and bromoenals catalyzed by NHC.All of the products were characterized by IR,1H NMR and high resolution massspectrum. The structures of some products were confirmed by13C NMR.