Study On Multicomponent Reactions In Water Media Or Under Solvent-free Condition

In the 21st century, green chemistry is one of an important development direction of chemistry and chemical engineering, is the inevitable choice of the human social and economic sustainable development. Thus, green chemistry has drawn much attention around the world. Development of the green catalysts and green solvents is also the focused area in our group.1. Development of environmentally friendly catalyst, and improvement of the atom economy.Catalyst is the basis of chemical processes, and the critical part to achieve the industrial applications. In recent years, organocatalyst has attracted chemists' interest at home and abroad due to the green characteristics such as metal-free, etc. The organocatalyst has not potential risks of leaching toxic metal ions into the environment; the reaction can be easily handled and performed in solution or under air without protection. The target product can be simply separated from reaction mixture and the organocatalyst can also be further recycled and reused.2. Using environmentally friendly media to meet the reqirement of green chemistry.Organic solvents are the most common reaction medium in traditional organic synthesis, but the toxicity of organic solvents and the difficulty to recycle make it harmful to the environmental factors. Therefore, restricting the use of organic solvents, using the novel green reaction medium (water, ionic liquids and/or supercritical fluid) instead of organic solvents, or avoiding the use of organic solvents (solvent-free conditions) has become an important research topic on green chemistry.Therefore, the organocatalyst and green solvents has gained the chemists' concern at home and abroad, and it has also been a hot point in green chemistry.In this thesis, a series of nitrogen-containing Lewis base are prepared to catalyze a series of multi-component reactions (MCR) for synthesis of important nitrogen-contained heterocyclic compounds under mild conditions. This thesis includes the following aspects:1.2-Amino-3-cyano-4-aryl-7,7-dimethyl-5-oxo-4H-5,6,7,8-tetrahydrobenzo[b]pyran derivatives are synthesized by use of aromatic aldehyde, malononitrile and dimedone via mutli-component reaction employing task-specific ionic liquid [PhCH2Me2N+CH2CH2NMe2]Cl-as organocatalyst with excellent yields. All reations have the merits of short reaction time, excellent yields, reusability of the catalyst.N-bromosuccinimide (NBS) is also employed in the reaction as catalyst. The drawback is the unreusability of NBS in this system.2. Spirooxindole derivatives are synthesized by use of indole, malononitrile and 1,3-dicarbonyl compounds via mutlicomponent reaction under solvent-, catalyst-free condition or water, catalyst-free condition with excellent yields. Comparing with the use of Lewis basic ionic liquids as catalyst, the two methods meet the requirements of green chemistry better.3.1,4-dihydropyrano[2,3-c] pyrazole derivatives are synthesized by use of aromatic aldehydes, malononitrile and 3-methyl-l-phenylpyrazole-5-ketone via mutli-component reaction employing task-specific Lewis basic quaternary ammonium salt as organocatalyst with excellent yields. All reations have the merits of short reaction time, excellent yields and reusability of the catalyst.4. Certain types of 1H-pyrazole [1,2-b] phthalazine-5,10-dione derivatives are synthesized by use of aromatic aldehydes, malononitrile and phthaloyl hydrazide via mutli-component reaction employing task-specific Lewis basic ionic liquid as organocatalyst. The method has the merits of short reaction time and excellent yields.