Synthesis Of Chromone Derivatives By DDQ-mediated Oxidative Cyclization

Chromone as an important structural unit,widely exists in natural products and synthetic compounds with biological activity.Therefore,the synthesis of chromone compounds has been widely concerned by chemists.Cross-Dehydrogenative Coupling(CDC)is a reaction that uses the C-H bonds in different reaction substrates under oxidizing conditions to directly form a C-C bond without functionalization.An effective method of carbon-carbon bonds.2,3-Dichloro-5,6-dicyanoquinone(DDQ),as an oxidant with good oxidation performance,has been widely used in CDC reactions in recent years.In this paper,using DDQ as an oxidant,through the CDC reaction,the synthesis methods of two chromone derivatives were studied.The specific contents are as follows:(1)The ring formation reaction of 1,3-diarylpropene and enaminones mediated by DDQ was studied.The reaction of 1,3-diarylpropene and enaminone uses 1,2-dichloroethane as the solvent,1.2 equivalents of DDQ as the oxidant,and reacts at room temperature for 2 hours.After separation through the column,3-ene with moderate to good yield is obtained Propyl chromone.First,the effects of different solvents,temperatures and other factors on the reaction efficiency were investigated,and the optimized reaction conditions were obtained.Then,the applicability of different 1,3-diarylpropenes and enaminones in the reaction was investigated.The experimental data is extended;finally,through a comparative experiment,the reaction mechanism of 1,3-diarylpropene and enaminone firstly coupled by C(sp3)-C(sp2)and the coupling product is hydrolyzed to form a ring is proposed.This reaction provides a safe and effective method for the synthesis of 3-allyl chromone.(2)The ring formation reaction of 1,3-diarylpropene and 2-aminochromone mediated by DDQ was studied.The reaction of 1,3-diarylpropene and 2-aminochromone uses 1,2-dichloroethane as the solvent,first add 1.2 equivalents of DDQ,react at room temperature for 2.5 hours,then add 2.1 equivalents of DDQ,and continue the reaction for 0.5 hours,Separation and purification to get azaanthrone.First,the effects of different solvents,temperatures and other factors on the reaction results were investigated,and optimized reaction conditions were obtained;then,the application of different 1,3-diarylpropenes and 2-aminochromones in the reaction was investigated Experimental data;finally,through a comparative test,it is proposed that 1,3-diarylpropene and 2-aminochromone are coupled by C(sp3)-C(sp2),and C(sp3)-N is coupled into Ring and dehydroaromatization reaction process.This study provides a simple and gentle method for the synthesis of azaanthrone compounds with wide biological and pharmacological activities.A total of 40 compounds were synthesized in the above research methods,all of which are new compounds,and the structures of all compounds were identified by means of nuclear magnetic and mass spectrometry.The cross-dehydrocoupling reaction studied in this paper provides an effective and feasible synthesis method for two chromone derivatives with wide biological activities.