Several Three-Component Reactions And Their Cascade Reactions

In recent years, the research and development of the multicomponent reactions (MCRs) has become a hot research topic in organic synthesis. In this dissertation, much attention has been focused on the systematical research on three categories of three-component cascade reactions. The details and results are summarized below:A simple, efficient and eco-friendly route has been developed for the synthesis ofβ-thio diketones via a three-component reaction of an aldehyde, acetylacetone and thiol in water. The influence of reaction conditions, such as solvents, ratio, time and substrate structures on the MCR was investigated. The experiment results demonstrated that the three-component reaction was influenced by the electronic and steric factors associated with substituents on aldehydes and the thiols. At the same time, the corresponding three-component reaction mechanism was proposed.A series of new, substituted 2,3-dihydropyran derivatives were synthesized by one-pot, three-component reactions of aldehydes,1,3-dicarbonyl compounds, and vinyl ethers catalyzed by ethylenediamine diacetate (EDDA) under solvent-free conditions. The effect of reaction conditions, such as catalysts, solvents, time, temperature, catalyst concentration and substrate structures on the MCR was investigated. The experiment results demonstrated that the optimum reaction condition was performed by using aldehyde (1 mmol),1,3-dicarbonyl compound (1.2 mmol), vinyl ether (3 mmol) in the presence of EDDA (10% mol) at 80℃under solvent-free conditions for 12 h. The structural assignment of cis- and trans-isomers was determined by spectral analysis of 1H NMR data and the X-ray single crystal analysis data. At the same time, the corresponding reaction mechanism was proposed.Bovine serum albumin (BSA) was found to catalyze the Gewald reaction for the first time. The influence of reaction conditions, such as solvents, time, temperature and substrate structures on the Gewald reaction was investigated in detail. The experiment results demonstrated that not only the reactivity of activated nitrile, but also the ring size of the aliphatic cyclic ketone and the chain length of the aliphatic branched chain ketone could influence the yield. The corresponding reaction mechanism was also proposed.An efficient one-pot procedure for the direct catalytic synthesis of substituted 2-aminothiophenes catalyzed by L-lysine in glycerol has been developed. The effect of reaction conditions, such as amino acid catalysts, solvents, time, temperature and substrate structures on the Gewald reaction and the recycle of glycerol were investigated in detail. The experiment results demonstrated that the L-lysine/glycerol reaction system could be recycled more than five times, with little loss of reactivity.In this dissertation,73 compounds were synthesized including 26β-thio diketone compounds,1β,γ-dithio ketone,2 Knoevenagel condensation products,19 substituted 2,3-dihydropyran derivatives, and 25 2-aminothiophene derivatives. These compounds were characterized by 1H NMR,13C NMR, FTIR and HRMS and 46 compounds have been confirmed to be new compounds.