【作者】 陈爱华；

【导师】 吴安心；

【作者基本信息】 华中师范大学 ， 农药学， 2007， 硕士

【摘要】 呋喃环，作为五员杂环化合物的典型代表，广泛地存在于自然界中，许多多取代呋喃是天然产物、重要药物的结构单元，显示了它们很强的生物活性，因此呋喃化合物的合成引起了广大化学家的浓厚兴趣。硫取代的呋喃是很活泼的中间体，在有机合成中有很广泛的用途，可以进行加成／消除反应，Ni-催化Grignard偶联反应，Michael加成，ortho-金属化反应，而且还可以进一步转化得到其它的呋喃衍生物。但是现有的将硫原子引入到呋喃环上的合成方法中，大多数对反应条件要求比较苛刻，而且多数方法是以本来就存在的呋喃环为前体来合成的。所以，用比较简单、有效的方法来合成硫取代呋喃有着重要的意义，具有广阔的应用前景。我们以芳基乙酮为原料，通过自分类串级反应(self-sorting tandem reaction)一步合成了2-硫甲基-2-烯-1，4-二酮化合物，分析该类产物的结构，我们不难看出它们是很好的合成3-位硫甲基取代呋喃的前体。我们采用修饰的Paal-Knorr合成法，在酸性条件下，将该类1，4-二酮产物顺利的转化为3-硫甲基-2，5-二芳基三取代呋喃化合物。而该类呋喃化合物上所连接的硫甲基易于还原，我们采用Raney Ni作为还原剂，成功地脱硫甲基，得到2，5-二芳基取代呋喃。(见Scheme 1)Scheme 1本课题的研究，我们采用芳基乙酮为原料，通过两步反应即可得到3-位硫甲基取代呋喃，具有原料简单易得，操作简便，总收率高等特点，不失为一种简单、高效的合成路径，将为该类硫取代呋喃化合物的合成提供一种新的合成思路。合成的3-硫甲基-2，5-二芳基三取代呋喃化合物均是未见文献报道的新型呋喃化合物，有望对其生物活性做进一步的研究。更多还原

【Abstract】 Furan, as one of the representive five-membered heterocycles, can be found in many naturally occurring compounds. Polysubstituted furans play an important role in organic chemistry due to their presence as key structural units in many natural products and in important Pharmaceuticals. For this reason the syntheses of polysubstituted furans continue to attract the interest of many synthetic chemist. Thio-substituted furans are particularly attractive intermediates that have found widespread usage in organic synthesis. They undergo a variety of reactions including addition/elimination, nickel-catalyzed Grignard coupling, Michael addition, ortho-metalation. Although a number of synthetic procedures are available for their formation, most of the existing methods often require harsh conditions and are frequently based on the use of a preexisting furan ring. So the development of mild method for the preparation of thio-furans from readily available starting materials is an active area of research and have broad application prospects.We have developed a new route to synthese 2-(methylthio) -2-ene-1, 4-dione from aryl methyl ketones via a self-sorting tandem reaction. It is well known that 1, 4-dione is a good precursor for the synthesis of furan via Paal-Knorr reaction and we converted the 1, 4-dione product into 3-methylthio-2, 5-diarylfuran via the modified Paal-Knorr condensation. The versatility of the MeS group was used to advantage by its ability to undergo reductive displacement to form diarylsubstituted furan, and reductive desulfuration of 3-methylthiofurans were achieved with Raney Ni in ethanol, (see Scheme 1)We have described a mild method for the preparation of 3-methylthiofurans via two steps from readily available aryl methyl ketones. Owing to the readily available starting materials, mild reaction conditions and good yields, this method should expand the scope of the formation of 3-methylthiofurans.更多还原