Study On Green Synthesis Of Aromatic Amide Compounds

Aromatic amides are commonly found in natural materials such as proteins and peptides.Due to their excellent characteristics of high stability,high polarity and biological activity diversity,they are widely used in the industrial raw materials,functional materials,prodrug intermediates and active drugs.At present,although various methods are found for the synthesis of aromatic amides,such as transition metal catalysis and organoboron coupling agent promotion,there exist some problems such as high cost,difficult subsequent separation of the metal and heavy pollution.Therefore,researchers are still committed to looking for more efficient,economical,safe and environment-friendly preparation methods which are suitable for the industrial production as well.Based on those researches,this paper developed several new experimental method systems for the preparation of aromatic amides respectively by using fused heterocyclic quinoline derivatives,monoheterocyclic pyridaldehydes and aromatic cyclobenzaldehydes as starting materials and air as oxidant.The specific study contents mainly include the following three parts:1.Study on the synthesis of quinolinamide derivatives.With 2-quinolinecarbal-dehyde,2-methylquinoline and 1,2-di(quinolin-2-yl)ethene compounds which are different in stability,quinolinamide were prepared by C-N coupling reaction using air as oxidant in different base promoters and solvents,and at the same time the experimental conditions were optimized respectively.Finally,a series of quinolinamide derivatives which contained different functional groups were successfully obtained by the substrate universality experiment.The method avoids the use of expensive coupling agents and difficult-to-handle transition metals.Furthermore,it replaces pure oxygen as oxidant with greener and safer air,which has the advantages of low cost,simple treatment,safety and environmental protection.2.Study on the synthesis of picolinamide derivatives.Taking the monocyclic heterocyclic pyridaldehyde instead of the fused heterocyclic quinoline de rivatives as the starting material,Further experimental research discovered that picolinamide could be obtained in the oxidative-coupling amidation of 2-pyridinecarboxaldehyde with aniline only by using air as oxidant at room temperature.Moreover,the alkali accelerator could significantly improve the reaction rate and yield of the amide product.By screening experiments,consequently,a new method for the efficient amidation reaction of 2-pyridinecarboxaldehyde with aniline at room temperature was established.The method features the advantages of mild condition,economic safety,high conversion efficiency and short time consumption.Furthermore,most functional groups have good tolerance.3.Study on the synthesis of benzanilide derivatives.On the basis of the previous experiments,with low-cost and readily available benzaldehyde which is aromatic ring compounds,the stable and direct C-N oxidation coupling reaction between benzaldehyde and aniline could be achieved by simply applying the oxidation system composed of alkali accelerator and air in heating condition.The method reduces the complicated "two-step conversion" which use acyl chloride or ester as intermediate and avoids the cost and pollution problems in metal catalysis.Moreover,the ratio of two types of reactants is equivalent with this method,which greatly improves the atom utilization and conforms to the new concepts of atomic economy and green chemosynthesis.