Synthesis Of Alkynyl Compounds And Benzothiazolones

Alkynyl compounds are not only useful synthons in organic synthesis, but also found in a wide range of natural products, medicines, organic materials and optical materials. It’s very important for synthesis of heterocyclic compound with biological and pharmacological activities. Research towards their synthetic methods has vital significance in organic synthesis. At present, considerable efforts were directed toward the development of transition metal catalyzed methods for their synthesis. However, use of transition metals has inherent drawbacks of high cost and toxicity and limited their wide application in drug synthesis. Thus the research towards transition-metal-free catalyzed approach for synthesis of alkynyl compound is a very promising field. Benzothiazolones are important structural units of various bioactive and pharmacological molecules. At present, synthesis methods for benzothiazolones were also limited to a certain extent because of poor substrate scope and harsh reaction conditions. Development of a novel method under the mild reaction condition has very vital significance in drug synthesis.The dissertation includes two parts of work:(I) the synthesis of alkynyl compounds from alkynyl halides;(II) copper catalyzed three-component synthesis of benzothiazolones by constructing C-S/C-N bond. The contents of this dissertation are summarized as follow:1. In the presence of Cul and1,10-phenanthroline, we firstly developed the preparation of ynamides from1,2-dibromo-1-alkenes with sulfonamides. Advantages of this method include readily available starting materials, good yields and mild reaction conditions. In addition, amidoindoles with pharmaceutical activities were synthesized by the palladium-catalyzed cyclization reaction2. A novel method for the synthesis of2-alkynyltetrahydrofuran derivatives and2-alkynyltetrahydrofuran derivatives has been developed. In the presence of sodium fluoride, alkynyl bromides,1,2-dibromo-l-alkenes were reacted with tetrahydrofuran at120℃to provide expected products in moderate to good yields. Furthermore, sodium fluoride was found to promote the efficient functionalization process remarkably through a radical mechanism.3. In the absence of any metals and additives, A atom-economic method for synthesis of bromo-substituted alkynyl sulfides from alkynyl bromides and tetrahydrothiophene has been developed under mild reaction conditions. The atom economy aspect of this method fits the concept of modern organic synthesis.4. In the presence of CuBr2, an efficient three-component reaction for the synthesis of benzothiazolones from o-iodoanilines, DMF, and potassium sulfide was developed. the reaction regarded DMF as carbon monoxide source to provide expected products. In addition, there are two advantages of readily available starting materials and good adaptability to the substrate.