【作者】 赵玄；

【导师】 史达清；

【作者基本信息】 苏州大学 ， 有机化学， 2011， 硕士

【摘要】 低价钛试剂是一种重要的还原剂,同时也是一种良好的催化剂,它具有较高的反应活性和选择性,由它引起的许多反应都可以在温和的条件下进行。本论文主要研究了低价钛促进下多官能团化合物的分子内及分子间的还原环化反应,并方便地合成了一些含氮杂环化合物。第二章研究了低价钛试剂作用下邻硝基苯甲酰胺与卤代酮及酮酸的还原环化反应,一步高产率地合成了3a-甲基-2,3,3a,4-四氢化吡咯并[1,2-a]喹唑啉-5(1H)-酮以及3a-甲基-2,3,3a,4-四氢化吡咯并[1,2-a]喹唑啉-1,5-二酮类化合物。产物的结构通过红外光谱、核磁共振氢谱、质谱和单晶X-射线衍射法确定,并提出了可能的反应机理。第三章研究了低价钛试剂(TiCl4/Zn)促进下2-邻硝基苯基咪唑与异氰酸酯的还原偶联反应,一步高产率的合成了咪唑并[1,2-c]喹唑啉-5(6H)-酮类化合物,产物的结构经红外光谱、核磁共振氢谱实验确证,并提出了可能的反应机理。第四章研究了低价钛试剂(TiCl4/Zn)促进下邻硝基查尔酮的还原环化,一步高效地合成了2-芳基喹啉-4(1H)-酮,该方法具有反应时间短,收率高和条件温和等优点,并通过红外光谱、核磁共振氢谱、高分辨质谱确证产物的结构,并提出了可能的反应机理。第五章研究了在低价钛试剂促进下的邻硝基亚胺的分子内的还原环化反应,一步高产率地合成了吲唑衍生物。产物的结构通过红外光谱、核磁共振氢谱、碳谱、高分辨质谱和单晶X-射线衍射法确定。以上所研究的反应都具有原料易得,反应条件温和,操作简便,立体选择性好,产率较高,以及原子经济等诸多优点。更多还原

【Abstract】 Low-valent titanium reagent is an important reducing agent, as well as a good catalyst. It shows high reactivity and selectivity and many reactions it caused can be carride out under mild conditions. Our interest is to investigate the intramolecular and the intermolecular reductive reactions of the multi-functional compounds induced by Low-valent titanium reagent to synthesis of a number of heterocyclic compounds containing nitrogen atom.In the second chapter, a novel reductive cyclization of 2-nitrobenzamides with haloketones or keto acids mediated by low-valent titanium reagent has been described. A series of 2,3,3a,4-tetrahydropyrrolo[1,2-a]quinazolin-5(1H)-one and 2,3,3a,4-tetrahydro- pyrrolo[1,2-a]quinazoline-1,5-dione were synthesized in good yields. The structures of the products were determined by IR, 1H NMR, HRMS and X-ray analysis. A possible reaction mechanism was put forward.In the third chapter, a short and reductive coupling reaction of 2-(o-nitrophenyl) imidazole and isocycanates induced by low-valent titanium reagent (TiCl4/Zn) was investigated. A series of imidazo[1,2-c]quinazolin-5(6H)-ones were synthesized in good yields. The structures of the products were determined by IR, 1H NMR analysis. And a possible reaction mechanism was put forward.In the forth chapter, an efficient synthesis of 2-arylquinolin-4(1H)-one derivatives via the reductive cyclization of o-nitrochalcone reduced by low-valent titanium reagent is described. This method has the advantages of short reaction time, high yield and mild reaction conditions. The structures of products were identified by IR and 1HNMR and HRMS spectra. A possible reaction mechanism was put forward.In the fifth chapter, a mild, efficient and novel synthesis of indazoles via cyclization of N-(2-nitrobenzylidene)aniline promoted by low-valent titanium reagent has been described. A series of indazoles were synthesized in good yields. The structures of the products were determined by IR, 1H NMR, 13C NMR, HRMS, MS and X-ray analysis.The remarkable advantages of the above mentioned reactions are mild, neutral, simple operation, good stereoselectivity, good yields and atomic economy.更多还原