【作者】 牛腾；

【导师】 胡雨来；

【作者基本信息】 西北师范大学 ， 有机化学， 2008， 硕士

【摘要】 Weinreb酰胺(N-甲基-N-甲氧基酰胺)是一类十分重要的酰基化试剂,与过量的金属有机试剂(如Grignard试剂)作用时,生成酮而不是醇。Weinreb酰胺也易于被金属氢化物还原为醛。目前已被广泛应用于天然产物及生物活性物质的合成。最近几年中,已发展了许多新合成方法。直接从羧酸出发,一步合成Weinreb酰胺是较理想的方法。但羧基必须先活化才可与N-甲基-N-甲氧基胺反应生成酰胺。因此它的制备仍然是一个具有挑战性的工作之一。本论文针对这一课题首先合成了N ,N′, N″-三甲基- N ,N′, N″-三甲氧基亚磷酰胺试剂,它是一个很好的酰胺化试剂,然后在温和的条件下,简捷高效的与羧酸反应,实现了直接从羧酸出发,一步合成Weinreb酰胺想法。鉴于近年来绿色化学的发展,我们研究小组也从绿色友好的角度出发,首次研究了微波、无溶剂下Weinreb酰胺的合成。本论文主要包括以下三个方面的内容:1.论文的第一章主要对Weinreb酰胺的产生、发展、制备及其在有机合成中的应用作了详细的总述。2.第二章主要研究了N ,N′, N″-三甲基- N ,N′, N″-三甲氧基亚磷酰胺试剂的制备和反应条件的优化。首次将其用于Weinreb酰胺的合成中,并研究了一系列底物在最优条件下的反应,实现了从羧酸一步高效合成Weinreb酰胺,其构型也不会发生转变,从而为天然产物结构多样性的羰基合成奠定了基础。3.第三章首次将微波、无溶剂技术引入到Weinreb酰胺的合成中。考察了微波辐射对合成Weinreb酰胺的作用。通过实验发现,在无溶剂下,亚磷酰胺与羧酸在微波照射下10分钟内即可完成反应。为实现环境友好合成,提供了一种简便、快速的合成方法。更多还原

【Abstract】 Weinreb amides (N-Methoxy-N-methyl amides) have become very important and effective acylating agents since its original discovery by Nahm and Weinreb in 1981. They can cleanly react with Grignard reagentsand and organolithium to give ketones even with excess of organometallc reagents. Because of their effectiveness as acylating reagents they have been used in synthesis of some natural products. Significant effort has been devoted toward the development of mild and general methods for their synthesis in recent years. Of all the methods the direct conversion of carboxylic acid to the corresponding Weinreb amides is a very attractive. Peptide coupling reagents are used in literature. It is one of the major important and more challenges to direct conversion of carboxylic acid to the corresponding Weinreb amides iorganic chemistry. Based on this point of view, a powerful reagent for synthesis of Weinreb amides is directly from carboxylic acid. Allowing for the recent development of the green chemistry, our research group set out from the green-friendly point, the synthesis of Weinreb amides was first touch upon under the condition of microwave and solvent-freeness. The following three parts are mainly included.1. In the first chapter, the product, development, preparation and application in organic synthesis of Weinreb amides, are reviewed in detail.2. In Chapter 2, the preparation of P(NOMeMe)3 reagent was mainly studied, and the reagent was used in the synthesis of Weinreb amides for the first time. It can produce Weinreb amide efficiency by carboxylic acid in one step, and the configuration of Weinreb amide will be unchanged. This will provide some theoretical bases of useful synthon for structural diversity of total synthesis of natural product.3. In Chapter 3, microwave and non-solvent technique was introduced in the synthesis of Weinreb amides. The influence of microwave radiation on the Weinreb amides was investigated. In this experiment, carboxylic acid reacts with P(NOMeMe)3 in 10 minutes, under the condition of non-solvent and microwave illumination. It provides a simple and fast method of synthesis of environment-friendship.更多还原