By ¦Á-cyano-cinnamic Acid Ethyl Ester Derivatives - Pot Synthesis Of 2 - Oxazoline

Oxazolines are very important five member heterocyclic compounds, which can be converted into other important compounds by regio-stereoselective ring-opening reactions. In another hand, they are the versatile sythetic intermediats of many compounds or natural products exhibiting potential biological and pharmaceutical activity. They have attracted attention by many chemists and biologists. In the past three decades, a synthetic methodology for preparation of oxazolines is one of hot research topic in organic synthesis. Researchs relateded to:exploring new catalysts; expanding substrate scopes; asymmetric synthesis and so on.Numerous synthetic methodologies of oxazolines have been developed though a variety of carboxylic acids, esters, nitriles withβ-amino alcohol and other substance. To find a new method for the synthsis of oxazolines, the idea of one pot for the synthsis of 2-oxazolines with ethylα-cnayo cinnamates as substrate was proposed.Ethylα-cnayo cinnamates, as derivatives of ethyl cinnamate, have similar properties to ethyl cinnamate. The activity of ethylα-cnayo cinnamates is more than latters with bearing a cnayo group.If the synthsis of 2-oxazolines from ethylα-cnayo cinnamates was succeeded, which can be easily reacted with nucleophilic reagents? Moreover, cnayo group can be converted into other important group in the mild condition, such as amino, acetamido, which make 2-oxazolines with cnayo group have wide application fields.Based on this research thought, in this paper, we have developed a new method for synthesis of 2-oxazolines using ethylα-cnayo cinnamates and N-Bromoacetamide (NBA) or acetamide/NBS in the presence of base. The advantages of these systems are mild, simple operation, good reaction selectivity, and wide range of products.The first chapter is a summary of research progress of synthesis of 2-oxazolines and the significance and the basis of this research.In the chapterⅡ, the new synthesic system of 2-oxazolines has been described, which use both of ethylα-cnayo cinnamates and N-Bromoacetamide (NBA) as basic starting materials catalyzed by K3PO4 to produce the bromoaminated products and then the closing ring reaction was occurred in the presence of K3PO4. Thirteen 2-oxazolines have been obtained which were characterized by 1H NMR and 13NMR andHM-MS. Many influencing factors for this reaction have been investgated such as category of catalysts, solvents and mol ratios of reaction starting materials. The reaction activety of difference substrate has been investigated through experiments. The activety of these ethyl a-cnayo cinnamates bearing electron-donating group is higher that that of bearing electron-donating group, such as ethyl p-methoxy-α-cnayo cinnamates can give a good yield. The reaction was completed within 2.5 h and gave corresponding product in excellent yield 98%, while the yield can be decreases to 79% when p-nitro-α-cnayo cinnamates reacted with N-BromoacetamideIn the chapterⅢ, another new synthesic system of 2-oxazolines has been described using ethyl a-cnayo cinnamates, mixture of acetamide/NBS in the presence of base. The structures of these products were characterized by 1H NMR and 13C NMR andHM-MS. The influencing factors for this reaction including catalysts, solvents and mol ratios of starting materials have also been investigated. The reactions activities of difference substrates have been investigated through experiments. The similar results are similar to the chapterⅡthat the activety of substance bearing electron-donating group is higher than that of bearing the electron-withdraw group.In summary, the new two synthesic systems of 2-oxazolines have been described, which use ethyl a-cnayo cinnamates as substances. The advantages of these systems are mild condition, simple operation and wide range of products.