Malononitrile-Involved Photocatalytic Multicomponent Reaction

The development of high yield,high selectivity,high utilization,mild reaction conditions,and simple and easy synthesis methods has always been one of the most active fields in the research of organic synthesis chemistry.In particular,the use of multi-component one-pot reaction for synthesis of heterocyclic compounds is of great significance.The photocatalytic chemical reaction is a synthetic method that aims at cleanliness,energy saving,and conservation.It is also one of the very active research fields in synthetic chemistry.First,according to the type of catalyst that used in the photocatalytic reactions,the photocatalytic multicomponent reactions have been reviewed in recent years.The multicomponent reactions involving malononitrile have been summarized.Based on these,combined with the advantages of photocatalysis and multi-component one-pot reaction,the multi-component reaction that involving malononitrile was studied,and some important heterocyclic compounds were synthesized.Spiropyrene pyrone derivatives are a class of compounds containing multiple heterocycles.They have a wide range of uses in medicine and exhibit a wide range of pharmacological activities such as anti-cancer,anti-inflammatory,anti-viral,anti-fungal.In the second part,according to the concept of"green chemistry",48spirocyclic indole derivatives have been synthesized via one-pot three-component reaction of malononitriles,isatin,and enolizable CH-activated compounds?2-hydroxynaphthalene-1,4-dione,4-hydroxycoumarine and dimedone?by using energy-saving LED light as radiation source,water/ethyl lactate as solvent at room temperature.In Chapter 3,the photocatalytic four-component reaction of salicylaldehyde,hydrazine and two-component malononitrile was investigated.Through the screening of light source,solvent,reaction temperature,the optimal reaction conditions were established.It was found the better reaction conditions:white light as a light source,no catalyst,in water ethyl-ethyl lactate solvent,at room temperature.The scope of application of this four-component reaction was investigated.This novel one-pot reaction provides an effective and convenient way for synthesis of2,4-diamino-5H-chromeno[2,3-b]pyridine-3-carbonitriles.In the fourth chapter,the reaction of aldehyde,cyanoacetone and malononitrile was studied.It was found that target product was obtained in 95%yield under blue LED irradiation in ethanol/H₂O?1:1?at room temperature for 5 hours.After obtaining the optimal reaction conditions,the substrate range of the reaction was investigated.Firstly,the effect of different aldehydes on the reaction was studied.For aldehydes with different substituents on the benzene ring,the products can be obtainedin high yield.In addition,for various substituted cyanoacetones,the reaction also yielded the target product in moderate to good yields.The method has the advantages of simple operation,mild reaction conditions and wide range of the substrates.A total of 111 compounds were synthesized in this work.Their structures were analyzed by IR,¹H NMR,¹³C NMR and mass spectrometry.