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选择性C-N键的形成及微波辅助分子内oxa-Michael加成反应
Study on Selective Formation of C-N Bond and Microwave-Assisted Intramolecular Oxa-Michael Addition Reaction
【作者】 洪一鸣;
【作者基本信息】 浙江工业大学 , 农药学, 2009, 硕士
【摘要】 本论文对选择性C-N键的形成及微波辅助分子内oxa-Michael加成反应进行了研究。以邻氨基苯甲酸类化合物和脒为原料,可方便地获得喹唑啉-4(3H)-酮类产物(1),1经POCl3氯化可到4-氯代喹唑啉化合物(2)。2与3-氨基-1H-吡唑化合物反应可得到两种类型的产物,在酸、碱条件下2的4位碳和3-氨基-1H-吡唑化合物的NH2发生C-N成键反应;在Pd催化条件下,2的4位碳则和3-氨基-1H-吡唑化合物的环内NH发生C-N成键反应。证明了两种反应条件下C-N键的形成是具有选择性的。论文对Pd催化下C-N成键的交叉偶联反应中的钯源、催化剂用量、配体、碱和反应温度等因素进行了优化。在无溶剂微波辅助作用下(E)-1-芳基-4-羟基-4-甲基-戊-1-烯-3-酮的分子内oxa-Michael加成反应中,Bronsted酸与Lewis酸均有催化活性,但Bronsted酸的催化活性高于Lewis酸的催化活性。以TfOH为催化剂,在优化的反应条件下,大部分反应都可在数分钟内完成,该反应对于芳基是取代苯环或萘环的的底物效果较好,能得到较高的原料转化率和产物选择性。这种方法的优点是反应时间短,对环境友好以及后处理简单。
【Abstract】 The selective formation of C-N bond and microwave-assisted intramolecular oxa-Michael addition reaction were studied in this thesis.Quinazolin-4(3H)-ones(1) were conveniently synthesized from anthranilic acids and amidines,which could be chloridized with POCl3 to obtain 4-chloroquinazolines (2).The reaction of 2 and 1H-pyrazol-3-amine would give two types of products.In the presence of acid or base,the C-N bond would be formed between the 4-position carbon of 2 and the NH2 of 1H-pyrazol-3-amine.While the C-N bond between the 4-position carbon of 2 and the NH of 1H-pyrazol-3-amine would be formed when Pd catalyst was utilized.It was confirmed that the C-N bond would be selectively formed under different reaction conditions.The influence factors in the Pd-catalyzed cross-coupling of 2 and 1H-pyrazol-3-amine,such as Pd source,the ratio of the catalyst,ligand,base and reaction temperature,were optimized.The acid-catalyzed intramolecular oxa-Michael addition of (E)-1-aryl-4-hydroxy-4-methylpent-1-en-3-ones under solvent-free and microwave irradiation conditions has been investigated.Experimental results showed Bronsted acids were more efficient than Lewis acids in this reaction.The microwave-assisted reactions could be finished within several minutes to give high conversion and selectivity.Substrates whose aryl groups were substituted phenyl or naphthyl groups were more suitable in this reaction.This method possessed such advantages as short reaction time.environmentally benign procedures and easy purification.