Synthesis Of 2,3-Dihydroquinazolin-4(1H)-ones Via Palladium-catalyzed Ortho-selective C-H Activation & Functionalization Of N-Substituted Anilines

2,3-Dihydroquinazoline-4(1H)-ones belong to an important class of nitrogen-containing heterocyclic compounds which have been found many applications in medicine and chemical industry due to their important biological and pharmacological activities.Thus,studies on their molecular design,synthesis and activity are still one of the hot topics in the medicinal chemistry research.Although there are a lot of synthetic methods developed for synthesis 2,3-dihydroquinazoline-4(1H)-ones,there still existed the following problems in different degrees complex,inconvenient availability,and high cost of the raw materials,low atomic economy,lengthy reaction steps,severe corrosion of equipment,and serious environmental pollution,etc.In this paper,an economical and facile approach was developed: with simple,cheap and easily available N-substituted anilines,CO,amines,aldehydes as the starting materials,the target compounds 2,3-dihydroquinazoline-4(1H)-ones were obtained directly via palladium-catalyzed ortho-selective C-H activation & functionalization of N-substituted anilines.Therefore,a new approach to 2,3-dihydroquinazoline-4(1H)-ones has been developed with the merits of low cost,short reaction steps,mild conditions,high atomic economy and friendly environment.This dissertation is divided into three parts:Chapter one,literature review.The following five parts are mainly included in this chapter:(1)The applications of 2,3-dihydroquinazoline-4(1H)-ones;(2)The main synthetic methods of 2,3-dihydroquinazoline-4(1H)-ones;(3)The introduction of palladium-catalyzed C(sp2)-H activation & carbonylation reactions;(4)The introduction of multi-component reactions;(5)The topic idea of this dissertation.Chapter two,synthesis of 2,3-dihydroquinazoline-4(1H)-ones via palladium-catalyzed ortho-selective C-H activation & functionalization of N-substituted anilines.In this chapter,with N-substituted anilines,carbon monoxide,amines and aldehydes or as starting materials,palladium acetate as catalyst,2,3-dihydroquinazoline-4(1H)-ones were prepared via palladium-catalyzed ortho-selective C-H activation & functionalization of N-substituted anilines.Factors affecting the reaction such as the content of reagent,the kind of solvent,the kind and amount of additive,the kind of oxidant,reaction temperature,reaction time were studied.Finally,a series of 2,3-dihydroquinazoline-4(1H)-ones were synthesized under the optimal conditions.Chapter three,mechanism discussion of palladium-catalyzed ortho-selective C-H activation & functionalization of N-substituted anilines to 2,3-dihydroquinazoline-4(1H)-ones.Depending on the experimental results and the literature information,the plausible mechanism was proposed.