Synthesis Of Terminal Alkyne With Disulfides, Diselenides And Tigafur Diselenides By The Catalyst Cesium Hydroxide

Cesium hydroxide, an inorganic super-base, has a good solubility in organic aprotic solvents. At room temperature, it can be effectively carried out in response to the air, and without the solvent-free water treatment. The reaction of Cesium hydroxide and organic weak acid (eg RC≡CH) in DMF (or THF, HMPA, DMSO, etc.) can form pro-nuclear material. Because the cesium ion is with large ionic radius, and its reaction with negative ions is small, it has strong nucleophilicity and its organic pro-nuclear reactions can be carried out efficiently under mild conditions.Of all the biological, sulfur is an important essential element. It is an integral part of many amino acids, which are an integral part of most proteins. Since that sulfur can be found in some common enzymes and amino acids such as Cysteine, methionine, homocysteine, taurine and so on, so sulfur is an essential element to all cells. Because of the biological activity of sulfur and its role in organic and drug synthesis, more and more chemists are of particular concern with sulfur compounds in recent years, especially the sulfur-olefin, which has a more accurate choice of regional selectivity and stereo and is an important intermediate for synthetic organic compounds. According to the literature, catalytic transition metals or toxic reagents are usually used in the syntheses of sulfur-based olefins. Thus, the reaction is characterized by high cost, serious pollution, poor selection, difficult separation, low yield and other shortcomings.In this thesis,cesium hydroxide catalysts the synthesis of acetylene with diaryl sulfides .It is founded that in the room temperature, DMSO as the solvent,we obtain the highly stereoselective (Z)-1,2-Dis(arylthio)alkenes.This method has many characteristics, such as low cost,simple operation,mild reaction condition, easy post-processing and so on.As an important part of antioxidant enzymes (glutathione peroxidase) and Se-P protein in animals and human beings, Selenium can balance redox in the body. Studies have shown that immune function has improved by Selenium, whose impact on the researches of immunity and cancer prevention is a hot topic in the field internationally. For years, scientists have synthesized a large number of biologically active organic selenium compounds. Because the biological activity of selenium and its role in the synthesis of transformation, carbon-selenium bond formation is a research chemist. The allyl selenides are important intermediates in organic synthesis, and plays an important role in organic selenium chemistry. In this theis, cesium hydroxide catalysts the synthesis of acetylene with diaryl sulfides . We can obtain highly stereoselective (Z)-1,2-diaryl selenium alkenes in DMF .Experimental results show that this method not only under mild conditions, simple operation, high yield and a single product.Tegafur is a derivative of fluorouracil, activated in the body by the liver and gradually changed into fluorouracil which has the function of anti-tumor. It is mainly used for gastrointestinal tumors, such as cancers in stomach, colon, rectal and pancreas, etc. Tegafur contains multiple functional groups. It is difficult to prepare tegafur diselenide using other methods and its synthesis is also not reported at present. This research is designed to synthesize tegafur diselenide. Then, in order to facilitate tegafur Diselenides into the structure of alkene, cesium hydroxide is used as a catalyst in the reaction of tegafur Diselenides tegafur with terminal alkynes, and in the end forms a new derivative of tegafur.