One-pot Synthesis Of Nitrogen-containing Heterocyclic Compounds Via Photocatalysis

Compared with traditional synthetic methods,visible light assisted reactions meet the requirements of mild reaction conditions,simple operation and environmental friendliness.Moreover,visible light is a readily available source,so it has promising applications in science and industry.Compared with the step method,the"one-pot"reaction requires no intermediate separation,which saves both energy and raw materials plus reduces time.According to the types of catalysts used in photocatalytic reactions,we have reviewed the visible light-catalyzed reactions in recent years.Then the photocatalytic three-,four-,five-,and six-membered nitrogen-containing heterocyclic compounds were summarized.Based on these,combined with the advantages of photocatalysis and multi-component one-pot reaction,some important nitrogenous heterocyclic compounds have been synthesized.In the second chapter,We have successfully developed a simple and efficient strategy for the synthesis of functionalized 2-amino-4H-pyran-3,5-dicarbonitrile derivatives.2-amino-4H-pyran-3,5-dicarbonitriles have received considerable attention because of their well-documented biological properties in the fields of natural products,pharmaceuticals,and agrochemicals.They can be used as antibacterial,antioxidant,antifungal,anticancer,and antiulcer agents,We follow the concept of"Green Chemistry",in environmentally friendly solvent,visible-light-initiated transformation to construct 2-amino-4H-pyran-3,5-dicarbonitrile derivatives via a one-pot,three-component reaction of isatins,malononitrile,and?-cyano ketones.In Chapter 3,the photocatalytic three-component reaction of isatins,malononitrile and linear?-dicarbonyl compounds was investigated.Through the screening of light source,solvent,catalyst,catalyst dosage,the optimal reaction conditions were established.It was found the better reaction conditions:green light as a light source,in water ethyl-ethyl lactate solvent,0.02 mmol eosin Y as catalyst.The scope of application of this three-component reaction was investigated.This novel one-pot reaction provides an effective and convenient way for synthesis of2-amino-4H-pyran derivatives.In the fourth chapter,highly efficient process for the synthesis of1,4-dihydropyridine derivatives has been devised.1,4-dihydropyridine derivatives were obtained via one-pot,four-component reaction of aromatic aldehyde,aromatic amine,malononitrile,and diethyl acetylenedicarboxylate in aqueous ethyl lactate under 10W white LED irradiation for 4h.It has the advantages of mild conditions,feasible operation and wide substrate range.A total of 98 compounds were synthesized in this work.Their structures were analyzed by IR,¹H NMR,¹³C NMR and mass spectrometry.