The Darzens condensation reaction of aromatic aldehydes with phenacyl chloride proceeded very efficiently in a water suspension medium in the presence of triethylbenzylammonium chloride and only trans 2,3 epoxy ...The Darzens condensation reaction of aromatic aldehydes with phenacyl chloride proceeded very efficiently in a water suspension medium in the presence of triethylbenzylammonium chloride and only trans 2,3 epoxy 1,3 diaryl 1 propanones were formed which can be isolated simply by filtration. The structures of these compounds were confirmed by elemental analysis, IR and 1H NMR spectra. Their configurations are in agreement with that of the same compounds reported in the literature. Compared to the classical Darzens condensation, this new method has the advantages of good yields, high stereoselectivity, low running cost inexpensive and environmentally benign procedure.展开更多
The kinetics of SN2 reaction between phenacyl bromide and various amines in 12 different solvents were studied. Solvent effects on the rate of this reaction and free energy of activation, ΔG#, were interpreted by app...The kinetics of SN2 reaction between phenacyl bromide and various amines in 12 different solvents were studied. Solvent effects on the rate of this reaction and free energy of activation, ΔG#, were interpreted by applying the Abraham-Kamlet-Taft (AKT) equation. The solvent polarity (π1*), solvent hydrogen-bond basicity (β1) and Hildebrand cohesive density energy (δ2H) are those parameters which increase the rate constant and decrease ΔG#, while solvent hydrogen-bond acidity (α1) will have the compensatory effect. A comparison among obtained values of second rate constants, k2 for different amines in a given solvent indicates that the amine reactivities are highly dependent on their structures. The consequent decrease of the rate constant for different amines in any given solvent was found to be: primary > secondary > tertiary. This order results from steric effects of amines.展开更多
An one pot method is used for the synthesis of 1,2,4,6 tetraaryl 1,4 dihydropyrazine by the reaction of phenacyl bromides with arylamines.This synthetic method provides an easier and simpler access to this kind of com...An one pot method is used for the synthesis of 1,2,4,6 tetraaryl 1,4 dihydropyrazine by the reaction of phenacyl bromides with arylamines.This synthetic method provides an easier and simpler access to this kind of compounds as compared with the that in reference.展开更多
The synthesis of C-substituted and N-substituted pyrrole is described by the reaction of phenacyl bromides, pentane-2, 4-dione and amine in aqueous medium using DABCO as a catalyst. The method is very convenient and a...The synthesis of C-substituted and N-substituted pyrrole is described by the reaction of phenacyl bromides, pentane-2, 4-dione and amine in aqueous medium using DABCO as a catalyst. The method is very convenient and applicable for alkyl as well as aryl amines and phenacyl bromides. The procedure is amenable for the synthesis of new substituted pyrroles. Moreover, aqueous medium makes the method more eco-friendly.展开更多
基金Projectsupportedbythe"QinglanGongcheng"FoundationofJiangsuProvince (No .QL980 0 1)
文摘The Darzens condensation reaction of aromatic aldehydes with phenacyl chloride proceeded very efficiently in a water suspension medium in the presence of triethylbenzylammonium chloride and only trans 2,3 epoxy 1,3 diaryl 1 propanones were formed which can be isolated simply by filtration. The structures of these compounds were confirmed by elemental analysis, IR and 1H NMR spectra. Their configurations are in agreement with that of the same compounds reported in the literature. Compared to the classical Darzens condensation, this new method has the advantages of good yields, high stereoselectivity, low running cost inexpensive and environmentally benign procedure.
文摘The kinetics of SN2 reaction between phenacyl bromide and various amines in 12 different solvents were studied. Solvent effects on the rate of this reaction and free energy of activation, ΔG#, were interpreted by applying the Abraham-Kamlet-Taft (AKT) equation. The solvent polarity (π1*), solvent hydrogen-bond basicity (β1) and Hildebrand cohesive density energy (δ2H) are those parameters which increase the rate constant and decrease ΔG#, while solvent hydrogen-bond acidity (α1) will have the compensatory effect. A comparison among obtained values of second rate constants, k2 for different amines in a given solvent indicates that the amine reactivities are highly dependent on their structures. The consequent decrease of the rate constant for different amines in any given solvent was found to be: primary > secondary > tertiary. This order results from steric effects of amines.
文摘An one pot method is used for the synthesis of 1,2,4,6 tetraaryl 1,4 dihydropyrazine by the reaction of phenacyl bromides with arylamines.This synthetic method provides an easier and simpler access to this kind of compounds as compared with the that in reference.
文摘The synthesis of C-substituted and N-substituted pyrrole is described by the reaction of phenacyl bromides, pentane-2, 4-dione and amine in aqueous medium using DABCO as a catalyst. The method is very convenient and applicable for alkyl as well as aryl amines and phenacyl bromides. The procedure is amenable for the synthesis of new substituted pyrroles. Moreover, aqueous medium makes the method more eco-friendly.
