【作者】 崔丽君；

【导师】 夏之宁；

【作者基本信息】 重庆大学 ， 化学， 2011， 硕士

【摘要】 苯并咪唑类化合物是一类重要的杂环化合物,具有抗病毒、抗菌、消炎等多种生理活性,在药物化学中具有非常重要的意义,因此一直是人们研究的热点。邻苯二胺和醛的反应是合成苯并咪唑类化合物的重要反应,目前未见该类反应机理的研究报道,而研究反应机理,对于理解反应历程,优化反应条件,提高反应收率有重要作用。微波作为一种新型的加热方式已经被广泛应用于有机合成领域。与常规加热相比,微波加热能够大大缩短反应时间或提高反应的产率,有时还表现出与常规加热不同的选择性。而红外作为另一种可以加热的电磁波,却较少被用于有机合成反应,如果红外也可以像微波一样明显促进反应的进行或改变反应的选择性,这种更加环保的加热方式将对有机合成领域产生重大影响。本文以合成2-(4-甲基苯基)苯并咪唑的反应为对象研究了该类反应的反应机理,并在微波辐射和红外辐射两种加热方式下进行该反应,考察了辐射加热对该反应的影响。本文亦对微波辅助N-芳基乙酰胺类化合物的合成及红外辅助水杨酸异丙酯的合成进行了研究,进一步考察了辐射加热对有机反应的影响。本论文由三部分构成,主要内容如下:第一部分由第2章构成。该部分以邻苯二胺和醛合成2-(4-甲基苯基)苯并咪唑的反应为研究对象,以高效液相色谱监测反应进程,对反应过程中的中间体和产物通过1H NMR、FT-IR及HPLC-MS等手段进行了结构确证,通过实验验证了该反应的机理。邻苯二胺和醛首先反应生成单席夫碱和双席夫碱,它们分别再转化为单取代苯并咪唑和双取代苯并咪唑;在胺和醛的摩尔比为1:1时,可同时生成单取代苯并咪唑与双取代苯并咪唑;单取代苯并咪唑的生成需要氧化过程,可被抗氧剂抑制;双取代苯并咪唑的生成是一个需要质子催化的过程,可被缚酸剂抑制,并且与反应溶剂的给质子能力有关。第二部分由第3章构成。该部分以邻苯二胺和醛合成2-(4-甲基苯基)苯并咪唑的反应为研究对象,采用商业化微波合成仪和自组装红外辐射反应器分别进行了该反应的微波辅助合成研究和红外辅助合成研究,考察了辐射加热对该反应的影响。在控制其他条件一致的情况下,微波加热下反应的产率比常规加热下略高,但差距不大,仅为1~10%;红外加热下的反应产率与常规加热下没有明显差别,红外辐射并不能明显促进该反应的进行。第三部分由第4章和第5章构成,该部分进行了辐射辅助其他有机反应的研究。首先研究了微波辐射对N-芳基乙酰胺类化合物的合成的影响,发现在相同的反应温度下,与常规加热相比,微波辐射能够促进该类反应的进行,产率能够提高4~25%,而且由于电子效应而产率较低的反应,微波对其促进作用更明显。然后研究了红外辐射对水杨酸异丙酯的合成的影响,发现在相同的温度下,红外辐射下的产率与常规加热下的产率几乎一致,说明红外辐射并不能促进该反应的进行。更多还原

【Abstract】 Benzimidazole is a very important class of heterocyclic compounds with antiviral, antibacterial, anti-inflammatory and other physiological activities, so it has become the focus of research. The reaction of o-phenylenediamine and aldehydes is an important way for the synthesis of benzimidazole, at present the mechanism of this reaction has not been reported. And the mechanism of reaction plays an important role in optimizing the reaction conditions and improving the reaction yield. The microwave technology is widely used in organic synthesis. Compared with conventional heating, microwave heating can increase the yield or shorten the reaction time significantly, and sometimes shows a different selectivity. Infrared is another electromagnetic wave which can provide heat. But infrared is less to be used in organic synthesis. If infrared can promote reactions or change the reaction selectivity as obviously as microwave, it will make a significant impact on the organic synthesis as a more environmentally friendly heating way. In this paper, the synthesis of 2-(4-methylphenyl) benzimidazole was studied for the mechanism of such reactions, and this reaction was heated by microwave and infrared radiation heating. Microwave-assisted the synthesis of N-aryl acetylamines and infrared-assisted the synthesis of isopropyl salicylate were studied, the influence of the radiation heating was investigated.This paper consists of three parts, the main contents are as follows:The first part includes Chapter 2. In this part, the reaction mechanism of the synthesis of 2-(4-methylphenyl) benzimidazole by o-phenylenediamine and aldehydes was studied. The reaction process was monitored by HPLC, and the structures of related intermediates and products were identified by 1H NMR, FT-IR and HPLC-MS. The results indicate that mono-schiff base and bis-schiff base could both be synthesized, and they could form mono-substituted and disubstituted benzimidazole respectively. In addition, it was found that an oxidation process was included in the transformation of mono-substituted benzimidazole from mono-schiff base. Furthermore, proton catalysis was necessary in the formation of disubstituted benzimidazole.The second part includes Chapter 3. In this part, Microwave-assisted and infrared-assisted the synthesis of 2-(4-methylphenyl) benzimidazole by o-phenylenediamine and aldehydes were studied using the commercial microwave synthesis instrument and self-assembly infrared radiation reactor. The influence of the radiation heating was investigated. Under the same experimental conditions, the reaction yield under microwave heating was slightly higher than that under conventional heating, but the difference between them was only 1~10%. There was no significant difference between the reaction yield under infrared heating and conventional heating. Infrared radiation has not promoted the reaction.The third part includes Chapter 4 and 5. In this part, radiation-assisted other organic reactions were studied. First, the reactions for the synthesis of N-aryl acetylamines synthesis were heated by microwave radiation and conventional heating in the same temperature. By comparison of the reaction yields in the two conditions, it was found that microwave radiation could promote reactions, the yields could be increased by 4~25%, and especially the reactions which were difficult to proceed because of the electronic effects. Then, infrared-assisted the synthesis of isopropyl salicylate was studied. The yield of infrared radiation and conventional heating were almost the same, so infrared radiation did not promote this reaction.更多还原