The Synthesis Of Amides Via Carbonylation Of CO And Other Organic Molecules Serving As Starting Materials By Photo-initiation Or Under Low-Temperature Conditions

Amide structure is one of the fundamental units in fine chemicals.It has been a hot research topic in organic synthesis through carbonylation reaction to construct-CO-NH-structure.However,traditional methods usually facing two major challenges including the design of catalytic systems and the choice of carbonyl sources.On the one hand,although noble metal catalysts have advantages in reactivity and efficiency in the catalytic process,their high costs,toxicity,and heavy metal residues problems still limit their applications on a large scale.On the other hand,CO as a kind of highly toxic gas is often required in excess under harsh reaction conditions(high temperature and high pressure),which limited the application of CO on basic research and industrial.Therefore,it has scientific significance to develop a clean,efficient and green method and system for carbonylation reactions.This thesis presents the study on the design and green synthesis of carbonyl-containing chemicals.Herein,we established an effective and environment-friendly method to construct amides compounds through direct photo-induced homolytic cleavage of aryl halides via the free radical process under ultraviolet light irradiation.In addition,we developed a mild system for the preparation of oxamide bis-carbonyl compounds use ascorbic acid as an acyl source without any catalyst.Based on all experimental evidence and theoretical calculations,we come to the following conclusions:(1)Under the excitation of 254 nm UV light,the carbonylation of aryl halides was realized without the participation of transition metals in aqueous phase.The corresponding aryl amide or aryl ester products can be obtained in a good yield of31%to84%under atmospheric CO pressure.The reaction system is extended to various organic amines(including primary amines,secondary amines,and tertiary amines)and alcohols(small molecule alcohols and aromatic alcohols).Generation chlorine radicals and aryl radicals via photo-induced homolytic cleavage of aryl halides is the prerequisite to the carbonylation process.The direct addition reaction of aryl radicals to CO to form acyl radicals and the hydrogen abstraction of amines or alcohols via chlorine free radical are the key steps in the completion of carbonylation process.(2)It is proved that ascorbic acid and its derivatives can be used as green and efficient carbonyl sources to complete the one-step synthesis of oxalamide.We established a facile(25?)and catalyst-free method to realize double carbonylation of ascorbic acid and serialized aliphatic or aromatic amines with good separation conversion of 54%to 97%.The key initial step of the reaction is the oxidative dehydrogenation of ascorbic acid under air atmosphere.This reaction mode can also be successfully used for the preparation of oxalate compounds.(3)The acetylation reaction of amines can be achieved under the thermocatalytic conditions(100?)of FeCl3 when acetonitrile with low toxicity and stability is used as acylating reagent.The amino group can be acylated with high selectivity when a reactive group such as an alcoholic hydroxyl group is present in the substrate structure.The reaction conditions of this system are simple and gentle which can avoid the use of traditional toxic acylating reagents such as acyl chloride.Isotope tracer tests have shown that the intermediate formed by acetonitrile and amine was hydrolyzed to form acetamide product.Water and acetonitrile are the direct sources of carbonyl and methyl groups respectively in the acetamide structure.The main innovation of this article is stated as follows:High selectivity and efficient synthesis of oxamide has been accomplished under catalyst-free conditions using ascorbic acid as the carbonyl source.It has been a creative way for non-toxic natural organic macromolecules in the functional group synthesis reaction.The use of acetonitrile as the acetyl source in the carbonylation reaction provides a new insight into the activation patterns and synthetic applications of acetonitrile and other inert substances.