Synthesis Of Hydroxyl Ionic Liquids And Their Application In C-C Bond Forming Reaction

Carbon-carbon bond formation is an important method to construct organic molecular skeleton and plays an important role in organic synthesis.The common reactions of carbon-carbon bond formation include Friedel-Crafts reaction,Mizoroki-Heck reaction,Suzyki-Miyaura cross-coupling reaction,Diels-Alder reaction,Knoevenagel reaction,Aldol reaction,Michael addition reaction,Morita-Baylis-Hillman reaction and so on.This kind of reaction is often accompanied by the use of toxic organic solvents,long reaction time or low yield.Based on this,chemists have optimized the reaction from different angles,and some of them have achieved some results.But from the aspects of catalyst design,environment-friendly solvent selection,and so on,to develop useful reaction systems for these reactions is still a very meaningful work.In recent years,ionic liquids have aroused the interest of chemists because of their excellent stability to water and air good solubility to organic and inorganic compounds,and easy functionalization.In this thesis,based on the perturbation of hydrogen bonds on organic reactions,a series of hydroxyl-containing ionic liquids were synthesized and used in Knoevenagel reaction,Morita-Baylis-Hillman reaction and Benzoin condensation reaction.By optimizing the reaction conditions and speculating on the reaction mechanism,an efficient method for promoting this kind of reactions was developed,the main content is as follows:Firstly,the hydroxyl-containing ionic liquid N-2-hydroxyethyl pyridine chloride was synthesized and used in Knoevenagel reaction.Compared with ionic liquids with similar structure as hydroxyl-free ionic liquids N-propylpyridine chloride and N-butyl pyridine chloride,it was found that the solvent-catalyst system composed of N-2-hydroxyethylpyridine,DABCO and water could efficiently promote the Knoevenagel reaction.Not only the reaction yield is high?83%-99%?,the reaction time is short?5-40min?,and the catalytic system can be reused.The second,a series of nitrogen-containing heterocyclic ionic liquids were synthesized by using 1,4-diazabicyclic[2.2.2]octane?DABCO?as substrates.Then mixed them with glycerol to obtain a series of deep eutectic solvents for Morita-Baylis-Hillman reaction.The results show that in the deep eutectic solvent composed of N-2-hydroxyethyl-DABCO chloride and glycerol?1:2?,except for the aromatic aldehydes with electron-donating group?-OH,-N?CH₃?₂?attached to the aromatic ring,and other aromatic aldehydes can obtain the target products with the yields of over 90%.Thirdly,a series of thiazole ionic liquids containing hydroxyl groups were synthesized by imitating the structure of vitamin B₁ and used as catalysts for the condensation of benzoin.It was found that 4-methyl-3-benzyl-5-??-hydroxyethyl?thiazolium salt was a better catalyst by adjusting the alkyl chain of ionic liquids and optimizing the reaction conditions.The target product was obtained in 99%yield in benzaldehyde benzoin condensation reaction.