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烯胺酮类化合物合成新工艺研究

Studies on the New Method of Synthesis of β-Enamino Ketones

【作者】 邓爵安

【导师】 申东升;

【作者基本信息】 广东药学院 , 药物化学, 2010, 硕士

【摘要】 烯胺酮类化合物是一类重要的医药中间体,在有机化学合成中具有非常广泛的应用。这类化合物兼有亲核性的胺基和亲电性的羰基两个反应中心,是一类多功能的合成子。它是合成吡啶、吡咯、吲哚、唑烷、嘧啶酮、喹啉等含氮杂环化合物的关键中间体;在合成3-氨基糖衍生物、生物碱类化合物、β-氨基衍生物中有非常重要的应用。氮原子和氧原子的存在使烯胺酮类化合物可以与主族金属或过渡金属形成六元配合结构,而使其成为一类潜在的有机金属配体。除此之外,烯胺酮类化合物本身还具有非常广泛的生理活性,这类化合物在农药和医药领域的应用也比较多,尤其是芳胺类烯胺酮类化合物,在抗惊厥、抗疟疾、抗病毒和治疗心血管疾病方面都表现出非常好的药理作用。目前有关烯胺酮类化合物的制备方法主要包括:(1)以β-二酮为反应底物在路易斯酸的催化下与芳香胺或者脂肪胺反应制备;(2)以氨基乙缩醛与酮通过缩合反应制备,反应多在溶剂二甲苯的回流下完成;(3)以端基炔烃、酰氯以及胺盐为原料经加成反应制备;(4)以杂环化合物的分解反应制备。然而,以上路线都存在着要么合成原料昂贵,要么需要使用有毒溶剂,反应条件苛刻,反应时间较长等缺点。本文开发了一条以α-羰基烯醇钠盐为关键中间体,通过两步反应制备烯胺酮类化合物的新工艺。我们对新工艺路线中的反应温度、溶剂、物料配比、反应时间等因素进行了考察,得到了新工艺的最优条件。第一步反应的溶剂为乙醚,催化剂为乙醇钠,底物酮和甲酸乙酯的物料配比为1: 2,反应温度为室温;第二步反应的反应溶剂为水,α-羰基烯醇钠盐与二甲胺盐酸盐的摩尔比为1: 2,反应温度为室温。在最优工艺条件下,我们合成了15个不同结构类型的烯胺酮类化合物,包括8个脂肪族的烯胺酮,6个芳香族烯胺酮和一个以苯乙腈为底物制备的烯胺腈类化合物,其中有10个产物为尚未见文献报道的新化合物。以上化合物都通过IR、MS、1H-NMR确定结构,通过对以上化合物的核磁共振数据和单晶衍射分析,对新工艺的化学选择性和立体选择性进行了考察。结果表明,新工艺对于带推电子基团的芳基取代的烯胺酮类化合物的制备都能得到较高产率,随着取代基的增大,反应的化学选择性越好,通过新工艺制备的烯胺酮类化合物均为反式结构。新工艺对于制备带有推电子取代基的芳香族烯胺酮类化合物均能得到较高的产率,产率大于90%。与已有的路线相比,新工艺具有绿色环保、原料便宜易得、反应条件温和,反应产率高等优势,具有非常好的工业化前景。

【Abstract】 β-Enamino ketones are a kind of important pharmaceutical intermediates, and their chemistry has drawn considerable attention in recent years.β-Enamino ketones are versatile synthetic intermediates that combine the ambident nucleophilicity of enamines with the ambident electrophilicity of enones, and have been extensively used for the preparation of a variety of heterocyclic derivatives including some natural products and analogues, such as indoles, pyridines and pyrroles; In coordination chemistry, enaminones can be used as good chelating ligands for main group metals and transition metals; Moreover, someβ-Enamino ketones exhibit very extensive pharmacological effects, especially in convulsions, malaria, antiviral treatment of cardiovascular diseases.At present, there are dozens of ways to synthesizeβ-Enamino ketones, including: (1) The condensation ofβ-diketones with amines catalysed by Lewis acid; (2) The condensation of ketones with DMFDEA, while xylene is used as reaction solvent; (3) Coupling of acid chlorides with terminal alkynes, and followed by subsequent addition of amnines access toβ-Enamino ketones, this procedure is catalysed by Pd(Ph3)2Cl2; (4) Decomposition of heterocyclic compounds to affordβ-Enamino ketones, however, the reaction is always associated with many side reactions. What’s more, expensive raw materials, toxic solvents, harsh reaction conditions, longer reaction time and other shortcomings are used in those synthetic routes.This paper has developed a new procedure, in which hydroxymethylene was used as the key intermediate, to synthesizeβ-Enamino ketones via two- step reactions. We have investigated a variety of reaction factors on the yield and got the optimized conditions: In the first step, ether is used as the solvent, sodium ethoxide as the catalyst, the ratio of acetophenone and ethyl formate is 1: 2, the reaction tempretrue is 25oC; In the second step, water as the solvent, the ratio is 1: 2.Fifteenβ-Enamino ketones were synthesized via the new procedure, including eight aliphatic enaminones, six aromatic enaminones and a enamine nitrile. All those structures were determined by IR, MS and 1H-NMR. we have studied chemical selectivity and enantioselectivity of the new procedure based on NMR data and single crystal diffraction data.The result of experiment indicates that the aryl-substituted ketones with electron-donating groups could afford excellent yield by the new procedure. The chemoselective increased with the increase of the steric hindrance of the substituent. The enantioselectivity of the new procedure is high, and theβ-Enamino ketones synthesized in this paper are all trans structures.

【关键词】 烯胺酮甲酰化α-羰基烯醇钠盐
【Key words】 β-Enamino ketoneformylationhydroxymethylene
  • 【网络出版投稿人】 广东药学院
  • 【网络出版年期】2011年 06期
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