The Regioselective Study Of Ethyl Levulinate And Benzaldehyde's Nucleophilic Addition Reaction

Nucleophilic addition reaction is one important class of organic reactions.We can get a variety of organic compounds and reaction intermediates by the reaction.The reaction of ethyl levulinate and benzaldehyde is a nucleophilic addition reaction with the catalysis of alkali.Owing to three lively methyl or methylene,ethyl levulinate can happen nucleophilic addition reaction with benzaldehyde in the presence of alkali,and we can get unsaturated ketones,carboxylic acids and other organic compounds by using its special regional selection. 3-benzylidene-levulinic acid,one of the products of this reaction,is the raw material of solubility 1,5-benzothiazepine which is a kind of compounds that have important physiological activities.Therefore,the nucleophilic addition reaction of ethyl levulinate and benzaldehyde,especially its regional selective research,is particularly important for organic synthesis.But there is no detailed study to be reported about the regional selection of the acetyl ethyl in the literature so far.The analysis method of the nucleophilic addition reaction of benzaldehyde and ethyl levulinate has been set up to study the regioselectivity in thesis by the impact of solvent,the type and concentration of the alkali(catalyst),reaction temperature,reaction time and reaction factors,and the reaction rule is obtained by studing the regioselectivity of the reaction systematically.In order to study the regioselectivity applicability for nucleophilic addition reaction of other substituted benzaldehyde and ethyl levulinate,seven kinds of benzaldehyde and ethyl levulinate's nucleophilic addition reaction have been studied.Experimental result shows that opposite-substituted benzaldehydes consistent with the rule.The main job of this thesis includes:[1]Establish HPLC analysis method of 3-benzylidene-levulinic acids which are the products of benzaldehyde and ethyl levulinate's nucleophilic addition reaction and verify the method's accuracy and precision.[2]Choose an appropriate synthetic route,14 kinds of standard samples of goal acids were synthesized by the reaction of substituted benzaldehyde and ethyl levulinate.The structures of these productions are determined by IR,~1H NMR analysis. [3]Use quantum chemistry to study the nucleophilic addition reaction's regional selection of benzaldehyde and ethyl levulinate by theoretical.The experimental research was performed for nucleophilic addition reaction's regional selection of benzaldehyde and ethyl levulinate by the influence on the reaction of the different types of alkali conditions,solvents, reaction temperature and alkali concentration.This reaction's rule is obtained and was explained by the results of quantum chemistry research.The optimal reaction condition and the worst reaction condition of the product(1a 3-benzylidene-levulinic acid) were founded according to this rule.[4]The applicability of the rule which obtained above was studied for the nucleophilic addition reactions of seven other kinds of benzaldehyde and ethyl levulinate.The experimental results show that opposite-substituted benzaldehydes and ethyl levulinate's nucleophilic addition reactions are accordance with it.