Research On Synthesis Of Quinoline Derivatives Base On 1,4-Dioxane Ring Opened

Quinoline compounds have been widely used in the fields of medicinal chemistry and organic electronic materials as one of the important nitrogen-containing heterocyclic compounds.Synthesis of quinoline compounds or formation of quinoline skeleton has been becoming a hot topic study in organic chemistry and has been attracted sustained attention.Quinoline compounds were mainly obtained by name reaction.In recent years,many novel,efficient,and convenient methods for the formation of quinoline skeletons have been developed under microwave,ultrasound,photocatalysis,and metal-free catalysis reaction condition based on green chemistry.Our research foucsed on oxidative dehydrogenative tandem cyclization of three components:2-methylquinolines（or arylaldehydes）,arylamines and 1,4-dioxane under metal-free catalysis and 2-（（2-arylquinolin-3-yl）oxy）ethan-1-ols and2-（[2,2’-biquinolin]-3-yloxy）ethan-1-ols were obtained.Detailed research was described as follows:1.A series of 2-（（2-arylquinolin-3-yl）oxy）ethan-1-ol derivatives were synthesized from raw materials arylaldehydes,arylamines and 1,4-dioxane by condensation reaction,oxidative dehydrogenation reaction of 1,4-dioxane,Povarov cyclization reaction,ring opening reaction and aromatization reaction in this transformation,which 1,4-dioxane was both used as solvent and reagent and provided a 2-（vinyloxy）ethan-1-ol group using ammonium iodide,dicumyl peroxide（DCP）as catalyst,oxidant,separately.This oxidative dehydrogenative cyclization reaction with cleavage of 5 C-H bonds,2 N-H bonds and 1 C-O bond will generate construction of 2 C-C bonds,1 C-N bond and 1 O-H bond through multi-step reactions.This strategy has some advantages such as cheap and readily avilable materials which did no pretreatment,without any metal.It will provide a novel and environmentally benign method for the synthesis of 2-（（2-arylquinolin-3-yl）oxy）ethan-1-ol derivatives.2.On the basis of the construction of 2-（（2-arylquinolin-3-yl）oxy）ethan-1-ol skeletons from arylaldehydes,arylamines and 1,4-dioxane,The reaction of 2-methylquinolines instead of arylaldehydes with arylamines and 1,4-dioxane was investigated to synthesize a series of2-（[2,2’-biquinolin]-3-yloxy）ethan-1-ol derivatives in“one pot”.Molecular iodine was used catalyst and tert-butyl hydroperoxide was used oxidant with 2 C-C bonds,1 C-N bond and 1O-H bond formtion and 7 C-H bonds,2 N-H bonds and 1 C-O bond cleavage in this process.The preliminary research on reaction mechanism has shown that this I₂-catalyzed oxidative dehydrogenative cyclization reaction come to be true construction of C-C bond,C-N bond and O-H bond by oxidative dehydrogenation reaction of methyl group and 1,4-dioxane,condensation reaction,Povarov cyclization reaction,ring opening reaction and aromatization reaction.Due to cheap and readily avilable materials and without any metal in this transformation,the method afforded an efficient and environmentally benign route for the rapid synthesis of 2-（[2,2’-biquinolin]-3-yloxy）ethan-1-ol derivatives.